Near-Collapse of Geomagnetic Field May Have Contributed to Diversification of Life on Earth

An ultra-weak geomagnetic field between 591 and 565 million years ago (Ediacaran period) coincided with a significant increase in the oxygen levels in the atmosphere and oceans, says a research team led by University of Rochester geoscientists.

Earth’s magnetic field was in a highly unusual state when macroscopic animals of the Ediacara Fauna diversified and thrived.

Image credit: NASA.

Between 600 and 540 million years ago, life on Earth consisted of soft-bodied organisms known as the Ediacaran Fauna, the earliest known complex multicellular animals.

The fossil record shows that these organisms significantly diversified in complexity and type between 575 and 565 million years ago

Previous research has suggested that this diversification is linked to a significant increase in atmospheric and oceanic oxygen levels that occurred over the same period.

However, it is not yet clear why this increase in oxygen occurred.

In the new study, University of Rochester’s Professor John Tarduno and colleagues analyzed the magnetic properties of 21 plagioclase crystals, a common mineral in Earth’s crust, which were extracted from a 591-million-year-old rock formation in Brazil.

Plagioclase crystals contain tiny magnetic minerals which preserve the intensity of the Earth’s magnetic field at the time they are formed.

An analysis of the crystals showed that, at their point of formation, the Earth’s magnetic field was the weakest ever recorded — some 30 times weaker than both the current magnetic field intensity, and that measured from similar crystals formed approximately two billion years ago.

The scientists combined their results with previous measurements to establish that the Earth’s magnetic field was at this weak level for at least 26 million years, from 591 to 565 million years ago.

This overlaps with the rise in oxygen, which occurred between 575 and 565 million years ago.

“The weakened magnetic field may have allowed more hydrogen to escape to space, resulting in a greater percentage of oxygen in Earth’s atmosphere and oceans, which may in turn have supported the diversification in the types and complexity of organisms,” the authors concluded.

• The findings were published in the journal Communications Earth & Environment.
• W. Huang et al. 2024. Near-collapse of the geomagnetic field may have contributed to atmospheric oxygenation and animal radiation in the Ediacaran period. Commun Earth Environ 5, 207; doi: 10.1038/s43247-024-01360-4

{ https://www.sci.news/ }

12-05-2024 om 00:49 geschreven door peter  

Krachtige zonne-explosies hebben een sterke impact op de aarde: wat zou er kunnen gebeuren?

 Door Janine

De krachtige uitbarstingen die op onze moederster exploderen, hebben een sterke impact op de aarde en lijken niet te stoppen. Dit is wat er gebeurt.

Wat zijn zonnevlammen?

SPACE WEATHER PREDICTION CENTER

Een zonnevlam, zo meldt NASA, is "een intense uitbarsting van straling door het vrijkomen van magnetische energie die gepaard gaat met zonnevlekken". Dit zijn, legt de Amerikaanse ruimtevaartorganisatie uit, de grootste explosieve gebeurtenissen in ons zonnestelsel. Ze manifesteren zich als heldere gebieden op de zon die enkele minuten tot enkele uren zichtbaar zijn.

Wat ons in staat stelt om ze te detecteren is het licht, dus de fotonen, die vrijkomen en die worden gecontroleerd door optisch licht en röntgenstraling. In zonnevlammen worden de zwaarste deeltjes versneld. De afgelopen dagen zijn zonnevlammen in volle actie: X1.6 vond plaats op 3 mei, gevolgd door andere krachtige fenomenen volgens het Space Weather Prediction Center van NOAA. Elk van deze fenomenen heeft een grote impact gehad op onze planeet.

De gevolgen van krachtige zonnevlammen op aarde

Een X1.3 en een X1.2 zonnevlam barstten op 5 mei los uit de actieve groep zonnevlekken AR 3663. In beide gevallen traden radio blackouts op op onze planeet, in Japan, Australië en grote delen van China, en de effecten zouden langer kunnen duren als coronale massa uitstoot, enorme wolken van zonneplasma doordrenkt met magnetische veldlijnen, geladen deeltjes naar de aarde zouden leiden.

Hierover zijn echter geen zekere gegevens bekend. Er zijn momenteel negen clusters zonnevlekken aanwezig aan de kant van de zon die naar onze planeet is gericht, die ongeveer 150 zonnevlekken omvatten. AR 3663 is op dit moment in ieder geval het meest actief en heeft sinds 30 april meerdere M-klasse en vier X-klasse vlammen uitgezonden, waarmee hij op de tweede plaats staat van de sterkste vlammen die onze ster kan produceren.

Maar wat zijn de voorspellingen van de wetenschappers en wat kunnen we verwachten? Volgens de voorspellers zullen er meer M-klasse vlammen zijn en mogelijk nog een of meer X-klasse vlammen voordat ze buiten de baan van de aarde draaien.

Keith Strong, een zonnefysicus, schreef in een bericht op X, voorheen Twitter: “Het gebied van zonnevlekken AR3663 produceerde een X4.5 vlam, de op twee na grootste sinds het begin van zonnecyclus 25 (4,3 jaar geleden)." Hij voegde eraan toe dat de vlam een sterke black-out veroorzaakte in een groot deel van Azië, Oost-Afrika en Oost-Europa. "Als het een coronale massa uitstoot produceerde, zal deze waarschijnlijk binnen een dag of twee de aarde raken."

Geomagnetische storm op komst? Er is iets positiefs aan

SDO | Solar Dynamics Observatory NASA

Zonnevlammen gaan soms gepaard met uitbarstingen die de aarde met een paar dagen vertraging kunnen bereiken, omdat plasma zich minder snel verplaatst dan licht. Op het moment dat de coronale massa uitstoot ons bereikt, ontstaat er echter een geomagnetische storm met aanzienlijke gevolgen voor de communicatie. Op het moment dat het de magnetosfeer van de planeet raakt, ontstaan er elektrische stromen die door elektriciteitsnetwerken kunnen reizen, stroomuitval kunnen veroorzaken en satellieten, radio- en navigatiesignalen kunnen beïnvloeden.

Maar er is ook een positief aspect: de wisselwerking tussen zonnedeeltjes, de magnetosfeer en de atmosfeer van de aarde leidt tot een opvallend poollicht boven de polen van de aarde, dat alleen 's nachts zichtbaar is, wanneer er geen zonlicht is. In elk geval zullen de volgende uitbarstingen kleine gevolgen hebben, omdat AR 3663 van de baan van de aarde af draait, maar de zon zit midden in haar activiteitscyclus, haar piek vindt om de elf jaar plaats en kan ons nog meer “verrassingen” bezorgen.

{ https://www.curioctopus.nl/ }

12-05-2024 om 00:31 geschreven door peter  

The sun appears to be angry; a massive coronal mass ejection unveils a striking image resembling a grimacing demonic face. Striking are the letters DV (DeVil?) standing out on the forehead of the figure. 

Obviously, the strange phenomenon captured by NASA's solar satellite SOLO EUI HRI 174 on 2024/05/11 is an ordinary natural occurrence triggered by the eruption of solar material but a fact is that a huge CME hit Earth's magnetic field on May 10th, leading up to the biggest geomagnetic storm in almost 20 year. 

And it is not yet over as forecasts predict additional coronal mass ejections to follow closely behind, prolonging the storm well into the weekend. Anticipation mounts for widespread auroras, promising captivating displays over regions like Europa and the United States. 

The storm has now reached level G5 which is the strongest level of geomagnetic storm, on a scale from G1 to G5. The solar storm could lead to disruption of satellite communication systems, low-frequency radio navigation systems such as GPS or even widespread power grid failures. 

This unique solar phenomenon emphasizes once more the importance of constant monitoring and readiness in response to solar disruptions in order to prevent another Carrington event which was the most intense geomagnetic storm in recorded history, peaking from 1–2 September 1859.

  

{ https://ufosightingshotspot.blogspot.com/ }

12-05-2024 om 00:18 geschreven door peter  

Cassini Observations Suggest Underground Ocean on Titan

Titan, the largest moon of Saturn, harbors an internal low-density ocean of water or ammonia, according to an analysis of archival data from NASA’s Cassini mission.

Representation of Cassini’s orbits used to calculate Titan’s gravity; the colored part of the orbits shows the distance from Cassini to Titan with the smallest distance in red; the cross-section of Titan shows the moon’s different layers with the ocean in blue; Saturn with rings and ring shadows can be seen in the background.

Image credit: Britt Griswold, NASA’s Goddard Space Flight Center.

“Liquid water is one of the prerequisites for the emergence of life,” said Dr. Sander Goossens from NASA’s Goddard Space Flight Center and colleagues.

“Water is rarely liquid on the surface of a planet, but a number of moons in our Solar System, such as Titan, contain underground oceans.”

“These probably formed long ago, which raises the question of why they are not yet frozen in the cold environment far from the Sun.”

“Our study supports the explanation that ammonia extended the life of the liquid ocean in Titan. In addition, it provides insight into Titan’s deeper layers.”

NASA’s Cassini mission explored Saturn and its icy moons for more than a decade.

Among its many instruments, Cassini carried a radio science subsystem that enabled Earth-based radiometric tracking of the spacecraft by the Deep Space Network.

These data were used to determine the gravity field and interior structure of several of Saturn’s moons as well as those of Saturn itself. Cassini data were also used to determine Titan’s tidal response.

“The Cassini space mission flew around Saturn between 2005 and 2017,” the researchers said.

“To precisely measure Titan’s gravity, the spacecraft was sent close to the moon several times.”

“Cassini had to skim past Titan at exactly the right time to properly map the change in gravity.”

“This is because Titan’s deformation is due to Saturn’s tidal force, which depends on the distance between Titan and Saturn.”

“By measuring at times when Titan is close and far away from Saturn, the difference in Titan’s deformation and thus its effect on gravity was maximum.”

From precise radar measurements, the scientists calculated Cassini’s velocity and then the change in gravity and Titan’s deformation associated with it.

They carefully examined the effect of tides on Titan at each location in the spacecraft’s orbit and concluded that the deformation is smaller than previously calculated.

Numerical simulations of the moon’s deformation for different internal structures show that the most likely scenario is that the ocean has a density similar to that of water with a small proportion of ammonia.

“An underground ocean can help transport organic material from a moon’s rock core to the surface,” the authors said.

“For Titan, it was assumed that a thick ice layer between the ocean and the core made this difficult.”

“Our analysis suggests that the ice layer is possibly thinner than previously thought, making exchange of material between rock and the ocean more plausible.”

“The organic molecules that this can produce are seen as important ingredients for the emergence of life.”

• The study was published in the journal Nature Astronomy.
• S. Goossens et al. A low-density ocean inside Titan inferred from Cassini data. Nat Astron, published online March 21, 2024; doi: 10.1038/s41550-024-02253-4

{ https://www.sci.news/ }

10-05-2024 om 23:20 geschreven door peter  

Look! This Strange Cosmic Cloud Looks Like a Dinosaur

This striking image of CG4 was captured by a telescope instrument originally built to study dark energy.

BY KIONA SMITH

 

NOIRLab

This strange cosmic cloud is called “the hand of God,” but it looks more like a Tyrannosaurus rex to us.

The reddish aura surrounding the cloud of gas and dust called CG4 comes from hydrogen gas, heated and ionized (electrically charged) by the radiation from massive nearby stars. That powerful bombardment of radiation is probably what eroded and stretched CG4 into its distinctive shape.

Astronomers call clouds like CG4 cometary globules, because their long, dust-shrouded tails look a bit like comets, even though they form completely different ways and on drastically different scales (one cometary globule probably contains a few star systems’ worth of actual comets). This one, CG4, is an especially dense patch of gas and dust within the larger Gum Nebula, which is home to the Vela Supernova Remnant and the Vela Pulsar.

Cometary globules like CG4 are just one form of a type of cosmic cloud called a Bok Globule. These clouds of gas and dust are so dense that visible and ultraviolet light can’t pass through them, making them appear as dark shadows in telescope images (when we can see them at all). The best way to see a Bok Globule is with an infrared telescope, like the Dark Energy Camera: an instrument mounted on the Victor Blanco Telescope on a mountaintop in Chile.

Weirdly, all of the 32 cometary globules in the Gum Nebula have their heads pointed toward the center of the nebula, where the fast-spinning Vela Pulsar lurks at the heart of the Vela Supernova Remnant; the pulsar and the expanding cloud of stellar debris around it are all that’s left of a massive star that exploded in a supernova about 1 million years ago. That explosion, along with radiation and charged particles from nearby massive stars in the Gum Nebula, may have shaped CG4 and other cometary globules into their streamlined shapes.

If you’d like a sense of scale, CG4 is about 1300 light years away. Its head is about 1.5 light-years wide, and its faint tail stretches across 8 light years.

{ https://www.inverse.com/ }

10-05-2024 om 21:57 geschreven door peter  

New NASA Visualization Shows Supermassive Black Hole’s Event Horizon

Thanks to a new visualization produced on a NASA supercomputer, you can plunge into the event horizon, a black hole’s point of no return.

“People often ask about this, and simulating these difficult-to-imagine processes helps me connect the mathematics of relativity to actual consequences in the real Universe,” said Dr. Jeremy Schnittman, an astrophysicist at NASA’s Goddard Space Flight Center.

“So I simulated two different scenarios, one where a camera — a stand-in for a daring astronaut — just misses the event horizon and slingshots back out, and one where it crosses the boundary, sealing its fate.”

To create the visualizations, Dr. Schnittman teamed up with Goddard Space Flight Center scientist Brian Powell and used the Discover supercomputer at the NASA Center for Climate Simulation.

They generated about 10 terabytes of data and took about 5 days running on just 0.3% of Discover’s 129,000 processors. The same feat would take more than a decade on a typical laptop.

The destination is a supermassive black hole with 4.3 million times the mass of our Sun, equivalent to the monster located at the center of our Milky Way Galaxy.

“If you have the choice, you want to fall into a supermassive black hole,” Dr. Schnittman said.

“Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”

This occurs because the gravitational pull on the end of an object nearer the black hole is much stronger than that on the other end. Infalling objects stretch out like noodles, a process astrophysicists call spaghettification.

The simulated black hole’s event horizon spans about 16 million miles (25 million km), or about 17% of the distance from Earth to the Sun.

A flat, swirling cloud of hot, glowing gas called an accretion disk surrounds it and serves as a visual reference during the fall.

So do glowing structures called photon rings, which form closer to the black hole from light that has orbited it one or more times.

A backdrop of the starry sky as seen from Earth completes the scene.

As the camera approaches the black hole, reaching speeds ever closer to that of light itself, the glow from the accretion disk and background stars becomes amplified in much the same way as the sound of an oncoming racecar rises in pitch.

Their light appears brighter and whiter when looking into the direction of travel.

The movies begin with the camera located nearly 640 million km (400 million miles) away, with the black hole quickly filling the view.

Along the way, the black hole’s disk, photon rings, and the night sky become increasingly distorted — and even form multiple images as their light traverses the increasingly warped space-time.

In real time, the camera takes about 3 hours to fall to the event horizon, executing almost two complete 30-min orbits along the way. But to anyone observing from afar, it would never quite get there.

As space-time becomes ever more distorted closer to the horizon, the image of the camera would slow and then seem to freeze just shy of it. This is why astronomers originally referred to black holes as “frozen stars.”

At the event horizon, even space-time itself flows inward at the speed of light, the cosmic speed limit.

Once inside it, both the camera and the space-time in which it’s moving rush toward the black hole’s center — a one-dimensional point called a singularity, where the laws of physics as we know them cease to operate.

The NASA visualization tracks a camera as it approaches, briefly orbits, and then crosses the event horizon — the point of no return — of a supersized black hole similar in mass to the one at the center of our Galaxy.

Image credit: J. Schnittman & B. Powell, NASA’s Goddard Space Flight Center.

“Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Dr. Schnittman said.

From there, it’s only 128,000 km (79,500 miles) to the singularity. This final leg of the voyage is over in the blink of an eye.

In the alternative scenario, the camera orbits close to the event horizon but it never crosses over and escapes to safety.

If an astronaut flew a spacecraft on this 6-hour round trip while her colleagues on a mothership remained far from the black hole, she’d return 36 min younger than her colleagues.

That’s because time passes more slowly near a strong gravitational source and when moving near the speed of light.

“This situation can be even more extreme,” Dr. Schnittman said.

“If the black hole were rapidly rotating, like the one shown in the 2014 movie Interstellar, she would return many years younger than her shipmates.”

{ https://www.sci.news/ }

09-05-2024 om 23:48 geschreven door peter  

Krachtige zonne-explosies hebben een sterke impact op de aarde: wat zou er kunnen gebeuren?

Door Janine

De krachtige uitbarstingen die op onze moederster exploderen, hebben een sterke impact op de aarde en lijken niet te stoppen. Dit is wat er gebeurt.

Wat zijn zonnevlammen?

SPACE WEATHER PREDICTION CENTER

Een zonnevlam, zo meldt NASA, is "een intense uitbarsting van straling door het vrijkomen van magnetische energie die gepaard gaat met zonnevlekken". Dit zijn, legt de Amerikaanse ruimtevaartorganisatie uit, de grootste explosieve gebeurtenissen in ons zonnestelsel. Ze manifesteren zich als heldere gebieden op de zon die enkele minuten tot enkele uren zichtbaar zijn.

Wat ons in staat stelt om ze te detecteren is het licht, dus de fotonen, die vrijkomen en die worden gecontroleerd door optisch licht en röntgenstraling. In zonnevlammen worden de zwaarste deeltjes versneld. De afgelopen dagen zijn zonnevlammen in volle actie: X1.6 vond plaats op 3 mei, gevolgd door andere krachtige fenomenen volgens het Space Weather Prediction Center van NOAA. Elk van deze fenomenen heeft een grote impact gehad op onze planeet.

De gevolgen van krachtige zonnevlammen op aarde

Een X1.3 en een X1.2 zonnevlam barstten op 5 mei los uit de actieve groep zonnevlekken AR 3663. In beide gevallen traden radio blackouts op op onze planeet, in Japan, Australië en grote delen van China, en de effecten zouden langer kunnen duren als coronale massa uitstoot, enorme wolken van zonneplasma doordrenkt met magnetische veldlijnen, geladen deeltjes naar de aarde zouden leiden.

Hierover zijn echter geen zekere gegevens bekend. Er zijn momenteel negen clusters zonnevlekken aanwezig aan de kant van de zon die naar onze planeet is gericht, die ongeveer 150 zonnevlekken omvatten. AR 3663 is op dit moment in ieder geval het meest actief en heeft sinds 30 april meerdere M-klasse en vier X-klasse vlammen uitgezonden, waarmee hij op de tweede plaats staat van de sterkste vlammen die onze ster kan produceren.

Maar wat zijn de voorspellingen van de wetenschappers en wat kunnen we verwachten? Volgens de voorspellers zullen er meer M-klasse vlammen zijn en mogelijk nog een of meer X-klasse vlammen voordat ze buiten de baan van de aarde draaien.

Keith Strong, een zonnefysicus, schreef in een bericht op X, voorheen Twitter: “Het gebied van zonnevlekken AR3663 produceerde een X4.5 vlam, de op twee na grootste sinds het begin van zonnecyclus 25 (4,3 jaar geleden)." Hij voegde eraan toe dat de vlam een sterke black-out veroorzaakte in een groot deel van Azië, Oost-Afrika en Oost-Europa. "Als het een coronale massa uitstoot produceerde, zal deze waarschijnlijk binnen een dag of twee de aarde raken."

Geomagnetische storm op komst? Er is iets positiefs aan

SDO | Solar Dynamics Observatory NASA

Zonnevlammen gaan soms gepaard met uitbarstingen die de aarde met een paar dagen vertraging kunnen bereiken, omdat plasma zich minder snel verplaatst dan licht. Op het moment dat de coronale massa uitstoot ons bereikt, ontstaat er echter een geomagnetische storm met aanzienlijke gevolgen voor de communicatie. Op het moment dat het de magnetosfeer van de planeet raakt, ontstaan er elektrische stromen die door elektriciteitsnetwerken kunnen reizen, stroomuitval kunnen veroorzaken en satellieten, radio- en navigatiesignalen kunnen beïnvloeden.

Maar er is ook een positief aspect: de wisselwerking tussen zonnedeeltjes, de magnetosfeer en de atmosfeer van de aarde leidt tot een opvallend poollicht boven de polen van de aarde, dat alleen 's nachts zichtbaar is, wanneer er geen zonlicht is. In elk geval zullen de volgende uitbarstingen kleine gevolgen hebben, omdat AR 3663 van de baan van de aarde af draait, maar de zon zit midden in haar activiteitscyclus, haar piek vindt om de elf jaar plaats en kan ons nog meer “verrassingen” bezorgen.

Source:

{ https://www.curioctopus.nl/ }

09-05-2024 om 23:38 geschreven door peter  

The search for life on Mars can be traced to the late 19th and early 20th centuries when Percival Lowell made extensive observations from his observatory in Flagstaff, Arizona. Inspired by Schiaparelli’s illustrations of the Martian surface (which featured linear features he called “canali”), Lowell recorded what he also believed were canals and spent many years searching for other indications of infrastructure and an advanced civilization. During the ensuing decades, observatories worldwide observed Mars closely, looking for indications of life and similarities with Earth.

However, it was not until the Space Age that the first robotic probes flew past Mars, gathering data directly from its atmosphere and taking close-up images of the surface. These revealed a planet with a thin atmosphere composed predominantly of carbon dioxide and a frigid surface that did not appear hospitable to life. However, it was the Viking 1 and 2 missions, which landed on Mars in 1976, that forever dispelled the myth of a Martian civilization. But as Fletcher told Universe Today via email, the possibility of extant life has not been completely abandoned:

“It’s my personal belief that it is unlikely we will find evidence of extant (current) life on Mars, as opposed to evidence of past life on Mars. If we were to find extant life on Mars that could be proven to be endemic to Mars and not contamination from Earth, some think it might be found underground in lava tubes, for example, and some think the ice caps or any possible source of liquid water might be suitable places.”

Ironically, it was the same missions that discredited the notion of there being life on Mars that revealed evidence that water once flowed on its surface. Thanks to the many orbiter, lander, and rover missions sent to Mars since the turn of the century, scientists theorize that this period coincided with the Noachian Era (ca. 4.1 – 3.7 billion years ago). According to the most recent fossilized evidence, it was also during this period that life first appeared on Earth (in the form of single-celled bacteria).

Our current astrobiology efforts on behalf of NASA and other space agencies are focused on Mars precisely for this reason: to determine if life emerged on Mars billions of years ago and whether or not it co-evolved with life on Earth. This includes the proposed Mars Sample Return (MSR) mission that will retrieve the drill samples obtained by the Perseverance rover in the Jezero Crater and return them to Earth for analysis. In addition, NASA and China plan to send crewed missions to Mars by 2040 and 2033 (respectively), including astrobiology studies.

These activities could threaten the very abodes where evidence of past life could be found or (worse) still exists. “Human activities might threaten sites like this in part due to possible microbial contamination,” said Fletcher. “Evidence of life (past and extant) also has greater scientific value when in its palaeoenvironmental context, so any human activities that might damage the evidence of life and/or its surrounding environmental context pose a risk. This could be something innocuous, like debris falling in the wrong spot, or something more serious, like driving over possibly significant outcrops with a rover.”

Conservation measures must be developed and implemented before additional missions are sent to Mars. Given humanity’s impact on Earth’s natural environment and our attempts to mitigate this through conservation efforts. In particular, there have been numerous cases where scientific studies were conducted without regard for the heritage value of the site and where damage was done because of a lack of proper measures. These lessons, says Fletcher, could inform future scientific efforts on Mars:

“It’s important that we learn from what has been considered “damaging” on Earth and take this into consideration when exploring Mars. If a site is damaged beyond being able to be studied in the future, then we limit what can actually be learned from a site. When considering Mars missions cost billions of dollars and are to meet specific scientific goals, limiting the information being learned from a site is incredibly detrimental. My recommendations are that of my paper: interdisciplinary cooperation, drawing on experience and knowledge from Earth, creating norms and a code of practice (part of my PhD work), and working towards creating legislation for these issues.”

The need for exogeoconservation is paramount at this juncture. In addition to Mars, multiple astrobiology missions will travel to the outer Solar System this decade to search for evidence of life on icy moons like Europa, Ganymede, Titan, and Enceladus. This includes the ESA’s JUpiter ICy moons Explorer (JUICE) mission, currently en route to Ganymede, and NASA’s Europa Clipper and Dragonfly missions that will launch for Europa and Titan in October 2024 and 2028 (respectively). Therefore, the ability to search for extant or past life without damaging its natural environment is an ethical and scientific necessity.

“I hope this paper is very much a starting point for anyone working in Mars science and exploration, as well as anyone thinking about space policy and exogeoconservation,” said Fletcher. “My goal was to start drawing attention to these issues, and that way start a generation of researchers and practitioners focused on exogeoconservation of Mars.”

Further Reading: 

• Space Policy

{ https://www.universetoday.com/ }

09-05-2024 om 22:53 geschreven door peter  

Earth is naked without its protective barrier. The planet’s magnetic shield surrounds Earth and shelters it from the natural onslaught of cosmic rays. But sometimes, the shield weakens and wavers, allowing cosmic rays to strike the atmosphere, creating a shower of particles that scientists think could wreak havoc on the biosphere.

This has happened many times in our planet’s history, including 41,000 years ago in an event called the Laschamps excursion.

Cosmic rays are high-energy particles, usually protons or atomic nuclei, that travel through space at relativistic speeds. Normally, they’re deflected into space and away from Earth by the planet’s magnetic shield. But the shield is a natural phenomenon and its strength fluctuates, as does its orientation. When that happens, cosmic rays strike the Earth’s atmosphere.

That creates a shower of secondary particles called cosmogenic radionuclides. These isotopes become embedded in sediments and ice cores and even in the structure of living things like trees. There are different types of these isotopes, including ones like Calcium 41 and Carbon 14.

Some of the isotopes are stable, and some are radioactive. The radioactive ones have half-lives ranging from only 20 minutes (Carbon 11) up to 15.7 million years (Xenon 129.)

When Earth’s shield weakens, more of these isotopes reach the planet’s surface and collect in sediments and ice. By studying these cores and sediments, scientists can determine the magnetic shield’s history. Their observations show that Earth experienced a geomagnetic excursion or reversal 41,000 years ago. It’s called the Laschamps excursion after the Laschamps lava flows in France, where geomagnetic anomalies revealed its occurrence.

Every few hundred thousand years, the Earth’s magnetic poles flip. North becomes South and vice versa. In between those major events are more minor events called excursions. During excursions, the poles shift around for a while without swapping places. The excursions weaken the Earth’s shield and can last from a few thousand to tens of thousands of years. When that happens, more cosmic rays strike the atmosphere, creating more radionuclides that shower down onto Earth.

Scientists often focus on one particular radioactive isotope in paleomagnetic studies. Beryllium 10 has a relatively long half-life of 1.36 million years and tends to accumulate on the soil surface.

Sanja Panovska is a researcher at GFZ Potsdam, Germany, who studies geomagnetism. At the recent European Geosciences Union (EGU) General Assembly 2024, Panovska presented new research on the Laschamps excursion. She found that during the Laschamps excursion, production of Be 10 was twice as high as normal.

To understand the Laschamps excursion more thoroughly, Panovska combined cosmogenic radionuclide and paleomagnetic data to reconstruct the Earth’s magnetic field at the time. She found that when the field decreased in strength, it also shrank. The transition from normal field to reversed field took about 250 years, and it stayed flipped for about 440 years. During the transition, the Earth’s shield weekend to as little as 5% of its normal strength. When it was fully reversed, it was at about 25% of its regular strength. This weakening allowed more Be 10 and other cosmogenic radionuclides to reach Earth’s surface.

These radionuclides do more than collect in sediments and ice. Some of them are radioactive. The weakening of the shield also weakened the ozone layer, letting more UV radiation reach Earth’s surface. The high-altitude atmosphere also cooled, which changed the wind flows. This could’ve caused drastic changes on the Earth’s surface.

For these reasons, the Laschamps event has been linked to the extinction of the Neanderthals, the extinction of Australian megafauna, and even to the appearance of cave art. Those links haven’t withstood scientific scrutiny, but that doesn’t mean that events like the Laschamps event aren’t hazardous. If it occurred now, it would knock out our power grids. The Earth’s equatorial region would light up with aurorae.

“Understanding these extreme events is important for their occurrence in the future, space climate predictions, and assessing the effects on the environment and on the Earth system,” Panovska said.

Scientists are learning that the magnetic shield isn’t static. There are anomalies. One of them is the South Atlantic Anomaly, a region where the magnetic field is weakest near Earth. When satellites pass over this region, they’re exposed to higher levels of ionizing radiation. The anomaly is likely caused by a reservoir of dense rock inside Earth, illustrating how complex the magnetic shield is.

Scientists are uncertain about what effect the cosmic rays have on life when the magnetic shield is weak. It’s tempting to correlate extinctions with events like the Laschamps excursion when they line up temporally. But the poles have shifted, weakened, and reversed many times and life is still here and still thriving.

If humanity lasts long enough, we’ll go through one of these reversals. Then we’ll know.

{ https://www.universetoday.com/ }

09-05-2024 om 22:40 geschreven door peter  

In one, the viewpoint plunges directly into the black hole like a free-falling astronaut, with explanatory text to guide us through what we’re seeing. The other is a 360-degree view of the black hole.

Schnittman created them with a NASA supercomputer called Discover in only five days, generating about 10 terabytes of data. The computer used only about 0.3% of its power. The same visualization would’ve taken more than a decade to create on an average laptop computer.

The black hole in the visualization is the same size as Sagittarius A star, the supermassive black hole (SMBH) at the heart of the Milky Way. It has 4.3 million solar masses and dominates the galaxy’s inner regions. Its event horizon reaches about 25 million km (16 million miles). That’s about 17% of the distance from Earth to the Sun. The event horizon is surrounded by an accretion disk, a swirling disk of superheated material drawn in by the black hole’s overpowering gravity.

Another type of black hole, the stellar-mass black hole, is much less massive. Schnittman says that if you’re going to fall into a black hole, you’d rather fall into the supermassive one.

“If you have the choice, you want to fall into a supermassive black hole,” Schnittman explained. “Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”

Powerful gravity is the reason. The SMBH’s gravity is so strong that it pulls harder on the end of the object nearest it. That stretches the object and elongates it. Stephen Hawking was the first to call this ‘spaghettification,’ and the name has stuck. Presumably, you’d get a better look if you fall into an SMBH.

In the movies, the camera begins at a distance of 640 million km (400 million miles.) Since space-time is warped around a black hole, so are the images of the sky, the black hole’s disk, and the photon ring. It takes the camera three hours of real-time to fall into the event horizon, and it completes almost two 30-minute orbits as it falls. A distant observer would never see an object ever reach the black hole. From a distance, the object would freeze at the event horizon.

When a falling object reaches the event horizon, it and space-time itself reach the speed of light. After crossing the horizon, the object and the space-time around it surge toward the singularity, a point of infinite density and gravity. “Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Schnittman said.

In the second video, the camera never crosses the event horizon and instead escapes. But the powerful black hole still has an effect. Imagine if the camera were an astronaut, and they flew this six-hour roundtrip while a separate astronaut stayed far away from the SMBH. The astronaut would return and be 36 minutes younger than the astronaut who never approached the black hole.

“This situation can be even more extreme,” Schnittman noted. “If the black hole were rapidly rotating, like the one shown in the 2014 movie ‘Interstellar,’ she would return many years younger than her shipmates.”

The bottom line is, don’t fall into a black hole. In fact, resist your fascination and don’t even approach one.

Leave them for the physicists.

{ https://www.universetoday.com/ }

09-05-2024 om 22:23 geschreven door peter  

The problems with AARO’s analysis weren’t overlooked by Mick West, arguably the most well-known UFO skeptic and the administrator of Metabunk, a website that crowdsources information West and other site contributors use to attempt to resolve UAP cases. In a posting on X following the release of AARO’s case analysis on the Eglin incident, West was quick to point out that the object in the photos obtained by the pilot bore little resemblance to images of a commercial lighting balloon used for comparison in AARO’s report.

“This Eglin UFO looks like a white sphere wearing a hat,” West wrote in his X posting that accompanied an image comparison he produced. “It shows a quite irregular ‘hat,’ which is not really consistent with the lighting balloon hypothesis.”

“I have never heard of ‘Earth Shine’ outside of the context of the Moon at night (or during a total eclipse),” West wrote in his posting at Metabunk. “But then the IC partner seems to think it’s direct illumination.”

“Their diagram is of little help,” West noted further, referring to an illustration in AARO’s report, which its authors use to explain why the lower portion of the object photographed by the pilot during the January 2023 incident might have appeared brighter than its upper portion, which West noted seems to be “at odds with the ‘earth shine’ theory.”

The Debrief reached out to West regarding his views on AARO’s analysis of the Eglin UAP case, as well as other issues that have arisen with official publications issued by the Pentagon’s UAP investigative office in recent weeks; most notably, AARO’s long-awaited “Report on the Historical Record of U.S. Government Involvement with Unidentified Anomalous Phenomena (UAP) Volume I,” which it released earlier this year.

For West, the lighting balloon theory falls short of offering a definitive resolution for the case, as do several of AARO’s other recent assertions.

“The lighting balloon hypothesis always felt like something someone at AARO liked, but wasn’t really supported by much evidence,” West told The Debrief in an email.

In an interview earlier this year with CNN’s Peter Bergen, Dr. Sean Kirkpatrick, the former director of the Pentagon’s All-domain Anomaly Resolution Office, made vague references to instances where ‘Tic-Tac’-shaped balloons produced by a Florida-based company were believed to have escaped.

“One of my favorite things is there’s this company in Florida,” Kirkpatrick told Bergen during the interview. “They make these backyard lighting balloons. Some of them are round. Some of them are tic tac shaped, and they’re black on the top, and inside, they have lights, and they’re helium filled. And they’re strapped down in people’s backyards for backyard parties, and they get away. When we talked to the company, they’re like, ‘yeah, we lose ’em. And we sometimes find them again, but generally not.”

Dr. Sean Kirkpatrick, former Director of the All-domain Anomaly Resolution Office

(Credit: NASA).

“Well, you know, that’s a really weird-looking thing. Lit from the bottom, not light on the top, big tic-tac thing, flying around. Well, what is that? That kind of stuff is a flight hazard,” Kirkpatrick told Bergen at the time, although offering no additional details on any instances where such an object was believed to have been mistaken for a UAP.

West told The Debrief that Kirkpatrick’s remarks had initially sounded “almost as if he was trying to explain the Nimitz Tic-Tac, which would be rather a stretch.” However, with the release of the AARO’s report on the Eglin UAP case, it is now clear that this was the incident Kirkpatrick had been referring to at the time. West says that although some kind of lighter-than-air object cannot be dismissed, even AARO seemed uncertain whether this was a definitive conclusion, despite the report now being categorized as resolved.

“In the Eglin case, it can’t be ruled out, but it’s also not the only hypothesis [AARO] put forward,” West points out, noting that AARO’s recent report on the incident suggests that the Eglin UAP had been “very likely a lighter-than-air object, such as a large commercial lighting balloon,” although the report’s authors express that limited data on the case makes it difficult to rule out other potential explanations.

One of the primary issues critics have raised with the balloon hypothesis is that while it could potentially explain a single object, such as the one photographed by the military pilot during the January 2023 incident, this theory becomes more difficult when attempting to apply it to all four objects initially observed on radar.

Although West concedes this point, he also notes that AARO’s report never claimed that the lighting balloon hypothesis could account for all the objects, which the pilot initially judged to have been holding a diamond-shaped formation and potentially remaining stationary amidst 80 mph winds. If anything, AARO’s investigators seemingly ignored the presence of the additional three objects detected on radar, apart from a brief mention of them near the outset of their report.

West says that while the release of radar data from the Eglin incident might be helpful in making further determinations about the other objects the pilot detected, some caution would still be warranted.

“There’s a long history of conflating radar data with visual sightings,” West told The Debrief. “Unless it can clearly be demonstrated, we need to be open to the idea that what was seen on radar was not the same thing as seen visually (or on other sensors).” West cites similar instances where radar returns may have been unrelated to the primary objects captured on camera, including a case investigated by the Chilean Navy several years ago, which, after initially being touted as an unknown, was quickly revealed to have been a conventional aircraft.

“In the Chilean Navy case, much was made of the fact that there was no object on radar where the pilots thought the object was,” West says, “because it was 3x as far away.”

“So [the Eglin] the radar data could be something else, an unrelated glitch, or maybe even something related to the object (like a radar jammer/spoofer).”

While these possibilities exist, fundamentally, it remains unknown what the radar data might actually entail since, in addition to very little being said about it in AARO’s report, it presently remains inaccessible to the public.

“The problem here is that we don’t have the data,” West says. “We have the assessments of multiple experts that the sum total of the available data points towards something non-anomalous and lighter than air.”

“But unfortunately, we can’t check their work.”

• 

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Asked if he felt that it would be helpful for independent analysts to review at least some of the additional data that was available to AARO investigators, West said that this might not only make AARO’s job easier, but it could potentially improve their analysis in significant ways.

“Ideally the data would be public, as the more eyes you have on something, the quicker issues and questions get resolved,” West told The Debrief. “AARO works with two partners, an IC (Intelligence Community) partner and an S&T (Science and Technology) partner. It’s not clear who they are, but they both seem to have reached similar conclusions. Oddly, neither seem to comment on the lighting balloon hypothesis, which suggests that it was internal to AARO, so three teams.”

One primary issue is that AARO, by virtue of its job within the government, often has to work with classified information related to various technologies and military operations. This limits its ability to properly communicate its findings and how much it can reveal about the experts and kinds of analysis from these three teams being employed in AARO’s investigations.

“The multi-domain and classified approach results in a fragmented report with very little visibility as to the workings of the three teams,” West says. “Adding more people, such as myself, or the broader public, would help iron out the inconsistencies and poorly communicated details.”

“There’s a risk it gets too messy, but I advocate for an approach called ‘curated crowdsourcing,’ which I described a few years ago,” West says, referencing an article in which he explains how crowdsourced information and analysis led to a reasonable explanation for the Chilean UAP footage within just a few days of its release.

Had the issues present in its recent report on the Eglin incident been the only instance where problems in AARO’s conclusions had been noted, some of the problems with its analysis might have been deemed innocuous. However, the release of the office’s proposed resolution for the 2023 Eglin UAP incident follows just weeks after the appearance of AARO’s Historical Record Report Volume I, which received a lackluster reception due to several factual inaccuracies it contained.

West shares some of those concerns about the mistakes in AARO’s recent publications, which he feels point to why independent analysis by civilian researchers is important.

“AARO should have had the report fact-checked and edited,” West told The Debrief. “They messed up.”

“They have multiple teams of highly paid people working with them, and they have done some good work. But putting out a report with lots of minor errors makes them look bad and casts doubt on their broader conclusions, such as the circular conversations leading up to the Kona Blue proposal and stories about crash retrievals.”

Unlike cases such as the Eglin UAP incident, which may involve reliance on some appropriately classified information, the public version of AARO’s historical report draws much of its contents from publicly accessible information. Additionally, an unclassified version of the report was planned for public release all along, as directed in legislation passed into law that required the completion and publication of the report.

Given that it was destined for public release anyhow, West told The Debrief that AARO might have benefited from having independent researchers offer feedback before the final version of the Historical Report was published.

“Since the report was going to be unclassified, there’s no reason why they could not utilize outside experts to review an embargoed version,” West says. “They could even contract with them, having them sign NDAs.

Fundamentally, West says that working more closely with independent researchers under such circumstances could have helped AARO produce a better, more accurate final report and may have reduced negative responses from many who, justifiably, viewed the report as lacking quality and factual merit.

“There’s no real downside,” West concluded, “and an error-free report is a much better way of conveying your research and conclusions than what they actually produced.”

• Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.

{ https://thedebrief.org/ }

09-05-2024 om 00:56 geschreven door peter  

New Study Explains Why Venus is Extremely Dry

Despite its Earth-like size and source material, Venus is extremely dry, indicating near-total water loss to space. Using computer simulations, planetary scientists from the University of Colorado, Boulder and the Laboratory for Atmospheric and Space Physics at the University of Arizona, Tucson found that hydrogen atoms in the planet’s atmosphere go whizzing into space through a process known as dissociative recombination — causing Venus to lose roughly twice as much water every day compared to previous estimates.

Venus today is dry thanks to water loss to space as atomic hydrogen.

Image credit: Aurore Simonnet / Laboratory for Atmospheric and Space Physics / University of Colorado at Boulder.

Despite being a close neighbor and being similar in size and source material to Earth, Venus is extremely dry.

Research has suggested that water from Venus’ once steam-dominant atmosphere was lost to space via a mechanism called hydrodynamic outflow.

However, this mechanism cannot remove all the water needed to explain current conditions, and other studied escape mechanisms are too slow to complete the process of water removal.

“Water is really important for life,” said Dr. Eryn Cangi, a researcher with the Laboratory for Atmospheric and Space Physics at the University of Arizona, Tucson.

“We need to understand the conditions that support liquid water in the universe, and that may have produced the very dry state of Venus today.”

“Venus is positively parched. If you took all the water on Earth and spread it over the planet like jam on toast, you’d get a liquid layer roughly 3 km (1.9 miles) deep.”

“If you did the same thing on Venus, where all the water is trapped in the air, you’d wind up with only 3 cm (1.2 inches), barely enough to get your toes wet.”

“Venus has 100,000 times less water than the Earth, even though it’s basically the same size and mass,” added Dr. Michael Chaffin, a researcher with the Laboratory for Atmospheric and Space Physics at the University of Arizona, Tucson.

The study authors propose a new explanation: a reaction called HCO+ dissociative recombination, which produces more escaping hydrogen than previously suggested processes.

HCO⁺ dissociative recombination would nearly double the rate of water loss to space from Venus and would resolve longstanding difficulties in explaining measured water abundances and isotope ratios on Venus.

Future Venus spacecraft missions need to measure HCO⁺ abundances to determine if HCO⁺ dissociative recombination is indeed the dominant mechanism for water loss.

“Our findings reveal new hints about why Venus, which probably once looked almost identical to Earth, is all but unrecognizable today,” Dr. Cangi said.

“We’re trying to figure out what little changes occurred on each planet to drive them into these vastly different states.”

• The results appear in the journal Nature.
• M.S. Chaffin et al. Venus water loss is dominated by HCO⁺ dissociative recombination. Nature, published online May 6, 2024; doi: 10.1038/s41586-024-07261-y

{ https://www.sci.news/ }

09-05-2024 om 00:34 geschreven door peter  

Ham, the Astrochimp Sent Into Space by NASA Before Alan Shepard and Neil Armstrong

On January 31, 1961, there was a special event in space history. A chimpanzee named Ham traveled into space, becoming the first of his kind to do so. Before famed astronauts like Alan Shepard and Neil Armstrong, there was Ham, a small chimpanzee, weighing only 37 pounds. Ham is remembered as both a hero and a creature who was put into a difficult situation during the space race.

Ham was part of a group of six chimps chosen for NASA’s Project Mercury. They were taken to Cape Canaveral in Florida, where they trained for three weeks in simulators designed to mimic the conditions of space. The purpose of sending Ham into space was to test if a spacecraft’s systems could keep a living creature safe and comfortable. This included making sure the life support systems worked during the short time of weightlessness in space.

Number 65 was a male chimpanzee, born in Africa in 1957. He was caught by trappers and taken to a bird farm in Florida. Then, in 1959, the U.S. Air Force bought him and took him to Holloman Air Force Base in New Mexico. There, he learned to be an astro-chimp, which is a chimpanzee trained for space missions. His handlers called him “Ham” because of where he was trained. Ham was one of 40 chimps picked for the space program.

Before sending humans to space, NASA wanted to see if they could do tasks there. They picked chimpanzees because they’re like humans in many ways. They wanted to see if chimps could do tasks in space that other animals couldn’t. In simple words, Ham was like a test subject to see if humans could survive a journey into space. According to NASA’s publication, This New Ocean: A History of Project Mercury, (“Ham Paves the Way” chapter):

Intelligent and normally docile, the chimpanzee is a primate of sufficient size and sapience to provide a reasonable facsimile of human behavior. Its average response time to a given physical stimulus is .7 of a second, compared with man’s average .5 second. Having the same organ placement and internal suspension as man, plus a long medical research background, the chimpanzee chosen to ride the Redstone and perform a lever-pulling chore throughout the mission should not only test out the life-support systems but prove that levers could be pulled during launch, weightlessness, and reentry.

The chimpanzees were trained to push buttons when they heard sounds or saw lights. If they did it right within five seconds, they got treats called banana pellets. If not, they felt a little shock on their feet. Scientists also made them experience what it’s like to feel strong forces and float in space, like the people training to go to space, called the “Mercury Seven.” They trained for almost two years.

The astrochimps were not trained to “pilot” space capsules. Instead, they were trained to do regular jobs during short space trips. They were also used as test subjects to understand the dangers of space travel, both physically and mentally. This helped scientists learn about the risks before sending humans, starting from the Mercury program and continuing into later space missions.

“According to one story, which strict scientists contend is apocryphal,” LIFE wrote, “a veterinarian gave a banana to a chimp before a rocket sled ride. As the animal peeled it, the ride started with a lurch and the monkey got the banana full in the face. The next time the chimp was offered a banana before a sled ride, he took it, peeled it, and smeared it over the veterinarian’s face.”

On January 31, 1961, a Mercury-Redstone launched from Cape Canaveral carrying the Ham over 400 miles down range in an arching trajectory that reached a peak of 158 miles above the Earth. Ham performed his lever-pulling tasks well in response to flashing lights. NASA used chimpanzees and other primates to test the Mercury capsule before launching the first American astronauts.

During the flight, his vital signs and various assigned tasks were closely monitored by computers back on Earth. At one point, the spacecraft lost some air because of a problem with a valve. But Ham was safe in his spacesuit. Ham’s journey in the spacecraft lasted for about 16 and a half minutes. He flew at around 5800 miles per hour and reached a height of 157 miles above the Earth. During part of the journey, he felt weightless for about 6 and a half minutes. Even with all the speed and strange feelings, Ham performed his tasks without any problem.

During the flight, they checked how Ham reacted to feeling weightless and speeding up by making him do tasks where he pulled levers. He had practiced doing these tasks before the flight. According to A Brief History of Animals in Space published by the NASA History Office, the flight did not go completely as planned:

The original flight plan called for an altitude of 115 miles and speeds ranging up to 4,400 mph. However, due to technical problems, the spacecraft carrying Ham reached an altitude of 157 miles and a speed of 5,857 mph and landed 422 miles downrange rather than the anticipated 290 miles… He experienced a total of 6.6 minutes of weightlessness during a 16.5-minute flight.

Read also:

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After the flight, when Ham’s capsule landed in the water, it was about 130 miles away from where it was supposed to be. The capsule started filling with water, but it took a few hours for a ship to come and rescue Ham. Amazingly, he was alive and seemed pretty calm, considering what he’d been through. His trainer described the moment he was recovered from his capsule following the project – “I have never seen such terror on a chimp’s face.” Biologist, Jane Goodall, would say his face showed “the most extreme fear.”

Later on, there was another moment that showed how scared Ham was. Some photographers wanted to take more pictures of him in his seat, but he refused to get back in. Even though people tried to make him, he wouldn’t do it.

After he flew into space, Ham lived alone for 20 years in the National Zoological Park in Washington D.C. Then, he moved to the North Carolina Zoo where he could be with other chimpanzees.

He died when he was only 26 years old on January 19, 1983. Some people wanted to make an exhibit of his stuffed body in a museum, but many disagreed. They thought it was disrespectful. An article in the Washington Post wrote, “Talk about death without dignity.” A letter in the Smithsonian Archives from a sophomore at West High School in Painted Post, New York, summed up the public mood: “By treating his body like that of a stupid beast, people will continue thinking of apes as stupid beasts, and not the intelligent, almost human animals they really are.”

Instead of being stuffed, Ham was cremated, and his ashes were buried with a plaque at the International Space Hall of Fame in Alamogordo, New Mexico. His bones are now shown at the National Museum of Health and Medicine.

{ https://www.howandwhys.com/ }

08-05-2024 om 21:52 geschreven door peter  

• Fragments of Planet Theia appear buried deep beneath Africa and the Pacific
• New evidence has emerged from deep within the moon via NASA's GRAIL craft
• READ MORE: Video spots 'space station' UFOs flying on dark side of the Moon

By MATTHEW PHELAN SENIOR SCIENCE REPORTER FOR DAILYMAIL.COM

A new study of metal ore deep inside the moon is offering fresh evidence that Earth's natural satellite was formed by an ancient planet crashing into Earth long ago.

This long-theorized interplanetary collision — which scientists believe occurred some 4.5 billion years ago — saw a Mars-sized planet named 'Theia' slice itself into hot lava fragments upon impact with the Earth.

While some of Theia's planetary remains appear to be buried as dense and massive 'blobs' deep underneath Africa and the Pacific Ocean's tectonic plates, scientists said evidence for where the rest of Theia went after this crash had remained elusive.

But now, new data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) spacecraft has found large telltale deposits of titanium-iron ore deep beneath the moon's surface, suggesting Theia's other remains did, in fact, form Earth's moon.

A new study of the moon is offering fresh evidence that Earth's natural satellite was formed by an ancient planet crashing into Earth. This long-theorized collision, some 4.5 billion years ago, saw a Mars-sized planet named 'Theia' slice into hot lava fragments upon impact with Earth

Under the moon's crust, in the region between the crust and the core known as the mantle, NASA's GRAIL craft detected two dense regions (pictured above) that match the titanium and iron 'ilmenite' deposits that would exist if the 'planet Theia' impact theory proves to be correct

Planetary geophysicist, Adrien Broquet of the German Aerospace Center in Berlin, described NASA's GRAIL findings as nothing short of 'mesmerizing.'

His team's new paper, published this April in Nature Geoscience, focused on 'gravity anomalies' deep under the moon's surface: dense, heavy pockets of matter identified by the GRAIL spacecraft's sensors.

'Analyzing these variations in the moon's gravity field allowed us to peek under the moon's surface and see what lies beneath,' Broquet said.

READ MORE: 

• Earth may have lost 60 percent of its atmosphere in the massive collision that formed the Moon 4.5 billion years ago

New research led by Durham University involved more than 300 supercomputer simulations designed to show the consequence of a huge collision on the planet. 

Under the moon's crust, in the region between the crust and the core known as the mantle, the GRAIL craft detected two dense regions that match the titanium and iron 'ilmenite' deposits that would exist if the Theia impact theory was correct.

After Theia's likely collision with Earth, and after fragments of this lost planet became buried deep below Earth's crust, molten lava pools of heavy titanium and iron on the moon's surface began to sink deeper towards its core, pushing lighter rock up.

'Our moon literally turned itself inside out,' said Broquet's co-author, Jeff Andrews-Hanna, a geophysicist at the University of Arizona's Lunar and Planetary Laboratory.

Computer models by their colleague, Nan Zhang at Peking University in Beijing, offered the original framework for their theory that titanium-rich material would exist deep within the moon as a result of the moon's origins as chunks of planet Theia. 

'When we saw those model predictions,' Andrews-Hanna said, 'it was like a lightbulb went on.' 

'We see the exact same pattern when we look at subtle variations in the moon's gravity field,' he said, 'revealing a network of dense material lurking below the crust.' 

Back on Earth, two similarly dense and unusual regions at the base of our planet's mantle — known as Large Low Velocity Provinces (LLVPs) — have also lent credence to the theory that an interplanetary 'Theia' collision created our moon.

One LLVP is located beneath the African tectonic plate and the other under the Pacific tectonic plate, as measured by seismic equipment similar to that used to detect earthquakes.

Their existence was established when geologists found that seismic waves slowed dramatically at a depth of 1,800 miles (2,900 km) in the two regions, which differed to other parts of the Earth.

Scientists have found new evidence our that the moon was created during a giant impact between Earth and a Mars-sized protoplanet called Theia 4.5 billion years ago. This also buried relics of Theia deep within Earth's mantle (depicted following the collision)

After running a series of simulations, Professor Hongping Deng discovered that following the moon-forming impact a significant amount of Theian mantle material – around two percent of Earth's mass – entered the lower mantle (shown in orange in the artist's impression above)

Scientists believe the material in these LLVPs is between 2 and 3.5 percent denser than the Earth's surrounding mantle. 

Last year, Researchers led by the California Institute of Technology came up with the idea that these LLVPs could have evolved from a small amount of Theian material that entered the ancient Earth's lower mantle. 

To back this up, they asked Professor Hongping Deng, of the Shanghai Astronomical Observatory, to explore this idea with the help of his pioneering methods in computational fluid dynamics.

After running a series of simulations, Professor Deng discovered that following the moon-forming impact a significant amount of 'Theian' material — around two percent of Earth's mass — would have entered the lower mantle of the ancient planet Earth. 

'Through precise analysis of a wider range of rock samples, combined with more refined giant impact models and Earth evolution models, we can infer the material composition and orbital dynamics of the primordial Earth, "Gaia," and "Theia,"' said Deng's co-author Qian Yuan, a CalTech geophysicist who also worked on this project.

Deng and Yuan's team published their study in the journal Nature late last year.

Broquet said he hopes future NASA missions to the moon, like those scheduled for the Artemis program, will be able to take similar seismic measurements: first-of-their-kind seismic data from the moon to better corroborate the Theia collision theory.

'Future missions, such as with a seismic network, would allow a better investigation of the geometry of these structures,' the researcher said. 

THEIA: AN ANCIENT PROTO-PLANET THAT MAY HAVE MERGED WITH THE YOUNG EARTH TO FORM THE MOOON

About 4.45 billion years ago, 150 million years after the solar system formed, Earth was hit by a Mars-size object called Theia.

The collision created the moon, but debate has raged exactly what happened during this event - and a mystery has persisted on why the moon and Earth are so similar in their composition.

The impact of Theia with Earth was so violent, the resulting debris cloud mixed thoroughly before settling down and forming the moon.

This cloud would have been composed of some Earth material, explaining the similarity between Earth and the moon, and other material.

The colliding body is sometimes called Theia, after the mythical Greek Titan who was the mother of Selene, the goddess of the Moon.

But one mystery has persisted, revealed by rocks the Apollo astronauts brought back from the moon - why are the moon and Earth so similar in their composition?

Several different theories have emerged over the years to explain the similar fingerprints of Earth and the moon.

Perhaps the impact created a huge cloud of debris that mixed thoroughly with the Earth and then later condensed to form the moon.

Or Theia could have, coincidentally, been isotopically similar to young Earth.

A third possibility is that the moon formed from Earthen materials, rather than from Theia, although this would have been a very unusual type of impact.

{ https://www.dailymail.co.uk/ }

08-05-2024 om 01:03 geschreven door peter  

The Sun is increasing its intensity on schedule, continuing its approach to solar maximum. In just over a 24-hour period on May 5 and May 6, 2024, the Sun released three X-class solar flares measuring at X1.3, X1.2, and X4.5. Solar flares can impact radio communications and electric power grids here on Earth, and they also pose a risk to spacecraft and astronauts in space.

NASA released an animation that shows the solar flares blasting off the surface of the rotating Sun, below.

Predicting when solar maximum will occur is not easy and the timing of it can only be confirmed after it happens. But NOAA’s Space Weather Prediction Center (SWPC) currently estimates that solar maximum will likely occur between May 2024 and early 2026. The Sun goes through a cycle of high and low activity approximately every 11 years, driven by the Sun’s magnetic field and indicated by the frequency and intensity of sunspots and other activity on the surface. The SWPC has been working hard to have a better handle on predicting solar cycles and activity. Find out more about that here.  

Solar flares are explosions on the Sun that release powerful bursts of energy and radiation coming from the magnetic energy associated with the sunspots. The more sunspots, the greater potential for flares.

Flares are classified based on a system similar to the Richter scale for earthquakes, which divides solar flares according to their strength. X-class is the most intense category of flares, while the smallest ones are A-class, followed by B, C, M and then X. Each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. The number that follows the letter provides more information about its strength. The higher the number, the stronger the flare.

Flares are our solar system’s largest explosive events. They are seen as bright areas on the Sun and can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, occurring in various wavelengths.

Sometimes, but not always, solar flares can be accompanied by a coronal mass ejection (CME), where giant clouds of particles from the Sun are hurled out into space.  If we’re lucky, these charged particles will provide a stunning show of auroras here on Earth while not impacting power grids or satellites.

Thankfully, missions like the Solar Dynamics Observatory, Solar Orbiter, the Parker Solar Probe are providing amazing views and new details about the Sun, helping astronomers to learn more about the dynamic ball of gas that powers our entire Solar System.

{ https://www.universetoday.com/ }

07-05-2024 om 21:29 geschreven door peter  

The names Brown and Batygin, both Caltech astronomers, come up often in regard to P9. Now, they’ve published another paper along with colleagues Alessandro Morbidelli and David Nesvorny, presenting more evidence supporting P9.

It’s titled “Generation of Low-Inclination, Neptune-Crossing TNOs by Planet Nine.” It’s published in The Astrophysical Journal Letters.

“The solar system’s distant reaches exhibit a wealth of anomalous dynamical structure, hinting at the presence of a yet-undetected, massive trans-Neptunian body—Planet Nine (P9),” the authors write. “Previous analyses have shown how orbital evolution induced by this object can explain the origins of a broad assortment of exotic orbits.”

To dig deeper into the issue, Batygin, Brown, Morbidelli, and Nesvorny examined Trans-Neptunian Objects (TNOs) with more conventional orbits. They carried out N-body simulations of these objects that included everything from the tug of giant planets and the Galactic Tide to passing stars.

29 objects in the Minor Planet Database have well-characterized orbits with a > 100 au, inclinations < 40°, and q (perihelia) < 30 au. Of those 29, 17 have well-quantified orbits. The researchers focused their simulations on these 17.

The researchers’ goal was to analyze these objects’ origins and determine if they could be used as a probe for P9. To accomplish this, they conducted two separate sets of simulations. One set with P9 in the Solar System and one set without.

The simulations began at t=300 million years, meaning 300 million years into the Solar System’s existence. At that time, “intrinsic dynamical evolution in the outer solar system is still in its infancy,” the authors explain, while enough time has passed for the Solar System’s birth cluster of stars to disperse and for the giant planets to have largely concluded their migrations. They ended up with about 2000 objects, or particles, in the simulation with perihelia greater than 30 au and semimajor axes between 100 and 5000 au. This ruled out all Neptune-crossing objects from the simulation’s starting conditions. “Importantly, this choice of initial conditions is inherently linked with the assumed orbit of P9,” they point out.

The figure below shows the evolution of some of the 2,000 objects in the simulations.

These are interesting results, but the researchers point out that they in no way prove the existence of P9. These orbits could be generated by other things like the Galactic Tide. In their next step, they examined their perihelion distribution.

“Accounting for observational biases, our results reveal that the orbital architecture of this group of objects aligns closely with the predictions of the P9-inclusive model,” the authors write. “In stark contrast, the P9-free scenario is statistically rejected at a ~5? confidence level.”

The authors point out that something other than P9 could be causing the orbital unruliness. The star was born in a cluster, and cluster dynamics could’ve set these objects on their unusual orbits before the cluster dispersed. A number of Earth-mass rogue planets could also be responsible, influencing the outer Solar System’s architecture for a few hundred million years before being removed somehow.

However, the authors chose their 17 TNOs for a reason. “Due to their low inclinations and perihelia, these objects experience rapid orbital chaos and have short dynamical lifetimes,” the authors write. That means that whatever is driving these objects into these orbits is ongoing and not a relic from the past.

An important result of this work is that it results in falsifiable predictions. And we may not have to wait long for the results to be tested. “Excitingly, the dynamics described here, along with all other lines of evidence for P9, will soon face a rigorous test with the operational commencement of the VRO (Vera Rubin Observatory),” the authors write.

If P9 is real, what is it? It could be the core of a giant planet ejected during the Solar System’s early days. It could be a rogue planet that drifted through interstellar space until being caught up in our Solar System’s gravitational milieu. Or it could be a planet that formed on a distant orbit, and a passing star shepherded it into its eccentric orbit. If astronomers can confirm P9’s existence, the next question will be, ‘what is it?’

If you’re interested at all in how science operates, the case of P9 is very instructive. Eureka moments are few and far between in modern astronomy. Evidence mounts incrementally, accompanied by discussion and counterpoint. Objections are raised and inconsistencies pointed out, then methods are refined and thinking advances. What began as one over-arching question is broken down into smaller, more easily-answered ones.

But the big question dominates for now and likely will for a while longer: Is there a Planet Nine?

Stay tuned

{ https://www.universetoday.com/ }

07-05-2024 om 21:18 geschreven door peter  

It’s that time again. NIAC (NASA Innovative Advanced Concepts) has announced six concepts that will receive funding and proceed to the second phase of development. This is always an interesting look at the technologies and missions that could come to fruition in the future.

The six chosen ones will each receive $600,000 in funding to pursue the ideas for the next two years. NASA expects each team to use the two years to address both technical and budgetary hurdles for their concepts. When this second phase comes to an end, some of the concepts could advance to the third stage.

“These diverse, science fiction-like concepts represent a fantastic class of Phase II studies,” said John Nelson, NIAC program executive at NASA Headquarters in Washington. “Our NIAC fellows never cease to amaze and inspire, and this class definitely gives NASA a lot to think about in terms of what’s possible in the future.”

Here they are.

1. Fluidic Telescope (FLUTE): Enabling the Next Generation of Large Space Observatories

Telescopes are built around mirrors and lenses, whether they’re ground-based or space-based. The JWST’s large mirror is 6.5 meters in diameter but had to be folded up to fit inside the rocket that launched it and then unfolded in space. That’s a tricky engineering feat. Engineers are building larger and larger ground-based telescopes, too, and they’re equally tricky to design and build. Could FLUTE change this?

FLUTE envisions lenses made of fluid, and the FLUTE team’s concept describes a space telescope with a primary mirror 50 meters (164 ft.) in diameter. Creating glass lenses for a telescope this large isn’t realistic. “Using current technologies, scaling up space telescopes to apertures larger than approximately 33 feet (10 meters) in diameter does not appear economically viable,” the FLUTE website states.

But in the microgravity of space, fluids behave in an intriguing way. Surface tension holds liquids together at their surfaces. We can see this on Earth, where some insects use surface tension to glide along the surfaces of ponds and other bodies of water. Also, on Earth, surface tension holds small drops of water together. But in space, away from Earth’s dominating gravity, surface tension is much more effective. There, water maintains the most energy efficient shape there is: a sphere.

Another force governs water: adhesion. Adhesion causes liquids to cling to surfaces. In the microgravity of space, adhesion can bind liquid to a circular, ring-like frame. Then, due to surface tension, the liquid will naturally adopt a spherical shape. If the liquid can be made to bulge inward rather than outward, and if the liquid is reflective enough, it creates a telescope mirror.

The FLUTE team would like to make optical components in space. The liquid would stay in the liquid state and form an extremely smooth light-collecting surface. As a bonus, FLUTE would also self-repair after any micrometeorite strike.

The FLUTE study is led by Edward Balaban from NASA’s Ames Research Center in California’s Silicon Valley. The FLUTE team has already done some tests on the ISS and on zero-g flights.

2. Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

It takes too long to get to Mars. It’s a six-month journey each way, plus time spent on the surface. All that time in microgravity, exposure to radiation, and other challenges make the trip very difficult for astronauts. PPR aims to fix that.

PPR isn’t a launch vehicle for escaping Earth’s gravity well. It would be launched on a heavy lift vehicle like SLS and then sent on its way.

PPR was originally derived from the Pulsed Fission Fusion concept. But it’s more affordable, and also smaller and simpler. PPR might generate 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. Those are good numbers. PPR could reduce the travel time to Mars to two months.

It has other benefits as well. It could propel larger spacecraft to Mars on trips longer than two months, carrying more cargo and also provide heavier shielding against cosmic rays. “The PPR enables a whole new era in space exploration,” the team writes.

PPR is basically a fusion system ignited by fission. It’s similar to a thermonuclear weapon. But rather than a run-away explosion, the combined energy is directed through a magnetic nozzle to produce thrust.

In phase two, the PPR team intends to optimize the engine design to produce more specific impulse, perform proof-of-concept experiments for major components, and design a shielded ship for human missions to Mars.

This study is led by Brianna Clements with Howe Industries in Scottsdale, Arizona.

3. The Great Observatory for Long Wavelengths (GO-LoW)

One of modern astronomy’s last frontiers is the low-frequency radio sky. Earth’s ionosphere blocks our ground-based telescopes from seeing it. And space-based telescopes can’t see it either. It’s because the wavelengths are so long, in the meter to the kilometre scale. Only extremely massive telescopes could see these waves clearly.

GO-LoW is a potential solution. It’s a space-based array of thousands of identical Small-Sats arranged as an interferometer. It would sit at an Earth-Sun Lagrange point and observe exoplanet and stellar magnetic fields. Exoplanet magnetic fields emit radio waves between 100 kHz and 15 MHz. The GO-LoW team says their interferometer could perform the first survey of exoplanetary magnetic fields within 5 parsecs (16 light years.) Magnetic fields tell scientists a lot about an exoplanet, its evolution, and its processes.

While there’s no doubt that large telescopes like the JWST are powerful and effective, they’re extremely complex and expensive. And if something goes wrong with a critical component, the mission could end.

GO-LoW takes a different approach. By using thousands of individual satellites, the system is more resilient. GO-LoW would have a hybrid constellation. Some of the satellites would be smaller and simpler satellites called “listener nodes” (LN,) while a smaller number of them would be “communication and computation” nodes (CCNs). They would collect data from the LNs, process it, and beam it back to Earth.

The GO-LoW says it would only take a few heavy launches to place an entire 100,000 satellite constellation in space.

The technology for the SmallSats already exists. The challenge the GO-LoW team will address with their phase two funding is developing a system that will harness everything together effectively. “The coordination of all these physical elements, data products, and communications systems is novel and challenging, especially at scale,” they write.

GO-LoW is led by Mary Knapp with MIT in Cambridge, Massachusetts.

4. Radioisotope Thermoradiative Cell Power Generator

It’s sort of like solar power in reverse.

The RTCPG is a power source for spacecraft visiting the outer planets. They promise smaller, more efficient power generation for smaller science and exploration missions that can’t carry a solar power system or nuclear power system. Both those systems are bulky, and solar power is limited the further away from the sun a spacecraft goes.

The thermoradiative cell (TRC) uses radioisotopes to create heat as an MMRTG does. But the TRC uses the heat to generate infrared light which generates electricity. In initial testing, the system generated 4.5 times more power from the same amount of PU-238.

Much of phase two’s work will involve materials. “Metal-semiconductor contacts capable of surviving the required elevated temperatures will be investigated,” the team explains. The team developed a special cryostat testing apparatus in phase one.

“Building on our results from Phase I, we believe there is much more potential to unlock here,” the team writes.

This power generation concept study is from Stephen Polly at the Rochester Institute of Technology in New York.

5. FLOAT: Flexible Levitation on a Track

What if Artemis is enormously successful? How will astronauts move their equipment around the lunar surface efficiently?

FLOAT would provide autonomous transportation for payloads on the Moon. “A durable, long-life robotic transport system will be critical to the daily operations of a sustainable lunar base in the 2030’s,” the FLOAT team writes.

The heart of FLOAT is a three-layer flexible track that’s unrolled into position without major construction. It consists of three layers: a graphite layer, a flex-circuit layer, and a solar panel layer.

The graphite layer allows robots to use diamagnetic levitation to float over the track. The flex-circuit layer supplies the thrust that moves them, and the thin-film solar panel layer generates electricity for a lunar base when it’s in sunlight.

The system can be used to move regolith around for in-situ resource utilization and to transport payloads around a lunar base, for example, from landing zones to habitats.

“Individual FLOAT robots will be able to transport payloads of varying shape/size (>30 kg/m^2) at useful speeds (>0.5m/s), and a large-scale FLOAT system will be capable of moving up to 100,000s kg of regolith/payload multiple kilometres per day,” the FLOAT team explains.

With their phase two funding, the FLOAT team intends to design, build, and test scaled-down versions of FLOAT robots and track. Then, they’ll test their system in a lunar analog testbed. They’ll also test environmental effects on the system and how they alter the system’s performance and longevity.

Ethan Schaler leads FLOAT at NASA’s Jet Propulsion Laboratory in Southern California.

6. SCOPE: ScienceCraft for Outer Planet Exploration

Some of the most intriguing planets and moons in the Solar System are well beyond Jupiter. But exploring them is challenging. Extremely long travel times, restrictive mission windows, and large expenses limit our exploration. But SCOPE aims to address these limitations.

Typically, a spacecraft carries a propulsion and power system along with its instruments and communication systems. NASA’s Juno mission to Jupiter, for example, carries a chemical rocket engine for propulsion, 50 square meters of solar panels, and 10 science instruments. The solar panels alone weigh 340 kg (750 lbs.) Juno is powerful, produces a wide variety of quality science data, and is expensive.

ScienceCraft takes a different approach. It combines a single science instrument and spacecraft into one monolithic structure. It’s basically a solar sail with a built-in spectrometer. They’re aiming their design at the Neptune-Triton system.

“By printing an ultra-lightweight quantum dot-based spectrometer, developed by the PI Sultana, directly on the solar sail, we create a breakthrough spacecraft architecture allowing an unprecedented parallelism and throughput of data collection and rapid travel across the solar system,” the ScienceCraft team writes.

Instead of merely providing the propulsion, the sail doubles as the spacecraft’s science instrument. The small mass means that ScienceCraft could be carried into orbit as a secondary payload. The team says they’ll use phase two to identify and develop key technologies for the spacecraft and to further mature the mission concept. They say that because of the low cost and simplicity, they could be ready by 2045.

“By leveraging these benefits, we propose a mission concept to Triton, a unique planetary body in our solar system, within the short window that closes around 2045 to answer compelling science questions about Triton’s atmosphere, ionosphere, plumes and internal structure,” the ScienceCraft team explains.

ScienceCraft is led by NASA’s Mahmooda Sultana at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

{ https://www.universetoday.com/ }

07-05-2024 om 21:01 geschreven door peter  

There’s also the Swedish Negative Ions on Lunar Surface (NILS), an instrument that will detect and measure negative ions reflected by the lunar surface. Lastly, there’s the Pakistani ICUBE-Q CubeSat developed by the Institute of Space Technology (IST) and Shanghai Jiao Tong University (SJTU), which will take images of the lunar surface using two optical cameras and measure the Moon’s magnetic field. The data these instruments provide will reveal new information about the lunar environment that will inform plans for long-duration missions on the surface.

By 2026, the Chang’e-6 mission will be joined by Chang’e-7, including an orbiter, lander, rover, and a mini-hopping probe. The data provided by the program will assist China’s plans to land taikonauts around the lunar south pole by 2030, followed by the completion of the ILRS by 2035.

Further Reading: 

• CGTN

{ https://www.universetoday.com }

06-05-2024 om 22:24 geschreven door peter  

Here are the 7 best places to search for life in the solar system

by Andy Tomaswick, Universe Today

If humanity is ever going to find life on another planet in the solar system, it's probably best to know where to look. Plenty of scientists have spent many, many hours pondering precisely that question, and plenty have come up with justifications for backing a particular place in the solar system as the most likely to hold the potential for harboring life as we know it. Thanks to a team led by Dimitra Atri of NYU Abu Dhabi, we now have a methodology by which to rank them.

The methodology, published in a recent preprint paper on arXiv, is focused on a new variable—the Microbial Habitability Index (MHI). MHI is intended to measure how habitable a specific environment is for the various types of extremophiles found in extreme places here on Earth.

As with many great engineering challenges, the authors broke down the process of developing an effective MHI into a series of steps. First, they defined a series of six environmental variables that can affect the habitability of a particular environment for life. They then defined six types of environments that are generally thought to exist on many potentially habitable worlds. They then picked seven of those habitable worlds and collected all the data they could on the environmental factors for each type of environment on each potentially habitable world.

With that data, they compared the values found in those environments to the values that extremophiles can live in. The results aren't particularly surprising to anyone interested in solar system astrobiology, but quantifiable data back them up. It seems Europa, Mars, and Enceladus are the most likely candidates to find bacterial life.

To get to this conclusion required a lot of data collection and quantification, though. First, the team had to define what environmental factors were the most important for the potential habitability of life. They settled on six: temperature, pressure, UV radiation, Ionizing radiation, pH, and salinity. Life can only survive in a narrow band of these values, and they serve as a reasonable basis for starting to think about what environmental features are necessary to support life.

Luckily, scientists have also collected data on life forms that thrive in the extremes of each of those six factors. From Serpentinomonas sp. B1 that can survive in pHs as high as 12.5 to Thermococcus piezophilus CDGS that can withstand pressures of up to 125 MPa, Earth's extremophiles give a good indication of what life might be able to contend with on other planets. Utilizing the highs and lows of the factors they selected, the scientists were able to determine the bounds an environment would have to conform to support life as we know it.

Those environments were the next things the scientists turned their attention to. They came up with a list of six potentially biologically interesting environments that were found to harbor life on Earth and then defined the ranges of the six environmental factors in each of those environments on Earth. Included in the list were: Icy Poles, Surface Continent, Subsurface Continent, Subsurface Ices, Ambient Ocean, Deep Ocean Floor, and Hydrothermal Vents. Each of those environments on Earth harbors life in some form, so the authors posit they could do so on some other world as well.

To find the most habitable places in the solar system, the researchers went down the list of worlds in the solar system. They eliminated most based on an outlier in one or more of the environmental factors they had defined as essential to biological life. At the end of their eliminations, though, they were left with seven potentially habitable worlds: Mars, Europa, Enceladus, Titan, Ganymede, Callisto, and (somewhat surprisingly) Pluto.

After getting all the selections out of the way, the authors got to the data collection phase. They collected data as much data as they could find about every time of environment that had been found on each of the worlds. Not every world is blessed with each of those environments, though. For example, Mars has no hydrothermal vents that we know of. However, that doesn't mean that other environments on the Red Planet wouldn't make a good candidate for astrobiology.

After collecting what data they could, they compared that data to the range defined by whether a microbe could withstand the ranges of environmental factors they would be subjected to at a given environment and, in so doing, came up with the MHI. The best way to summarize the outcome of their calculations is through a table showing the number of environmental factors that fall within the habitable range of extremophiles for each of the six environments selected as part of the study. The table is reproduced below.

The denominator in each of the entries signifies how many of the environmental factors the researchers could find data on. If the number is less than six, the researchers could not find data on one or more of the factors. The numerator in each fraction is the number of those environmental factors that lie within the bounds of environmental habitability for each. So, for example, the 1/4 value in the Subsurface Ice row of the Titan column means that there were data points available for four of the six environmental factors and that one of those environmental factors laid within the bounds set by the minimum and maximum of the livable conditions of extremophiles.

The chart clearly indicates that the most likely place that life could exist in the solar system is Enceladeus' hydrothermal vent system, which scores a five out of five on potential environmental factors—it is missing data on ionizing radioactivity. But the icy moon isn't alone at the top of the potentially habitable list. Mars and Europa both harbor environments that could be habitable to life, though the other candidates on the list seem less hospitable.

Ultimately there are a series of missions that will be focused on finding any microbial life that might exist at many of these locations, including Europa Clipper and the Mars Sample Return mission. This paper provides yet another reason why Enceladus should have its own mission in the works. But for now, having the framework that lets researchers and engineers focus their efforts on the most likely places to find one of the most sought-after discoveries in human history will help focus their efforts. Maybe something will come of it in the long run.

More information: 

• Dimitra Atri et al, Assessment of Microbial Habitability Across Solar System Targets. arXiv:2203.03171v2 [astro-ph.EP], doi.org/10.48550/arXiv.2203.03171

{ https://phys.org/space-news/ }

06-05-2024 om 18:12 geschreven door peter  

Why Venus May Be Our Best Bet For Finding Life In the Solar System

Venus and Earth once looked a lot alike. Could our planet’s forgotten early twin also contain life?

BY KIONA SMITH

 

One of the weirdest places in our Solar System may actually be a great place to search for alien life: the skies of Venus.

We don’t have evidence of life — or even indisputable evidence that life could survive — in any world but the one we currently live in. However, recent years have raised the tantalizing prospect that our Solar System, in which we thought we were alone, may be dotted with diverse, and deeply weird, homes for life: In dark water beneath the ice of Europa and Enceladus, in briny underground refugia on Mars, and even drifting in the acidic clouds of Venus.

“If it had liquid water in the past, and if we can really confirm that, then yes – Venus would likely be the planet I would place my bet on,” University of Wisconsin-Madison planetary scientist Sanjay Limaye tells Inverse.

Limaye and his colleagues, along with several other teams of researchers, presented their work in a recent collection of papers in the journal Astrobiology.

BETTING ON VENUS

In a series of recent papers, several teams of planetary scientists and astrobiologists argue that although the surface of Venus is undeniably an uninhabitable hellscape — you can’t do organic chemistry in a place that’s hot enough to melt lead — the sulfuric acid clouds might actually contain just enough water and other key chemicals for microbes to make a living.

What we know about Venus suggests that there’s something going on in our evil twin planet’s atmosphere that we don’t understand yet, whether it’s alien life or unusual chemical reactions that we’ve never seen anywhere else is still hotly debated.

A few years ago, a team of scientists detected a chemical called phosphine in Venus’s atmosphere. Here on Earth, the chemical reactions that create phosphine only ever happen inside living things, so some astrobiologists immediately got very excited about its presence on Venus. But in a recent paper, chemist Klaudia Mráziková of the Czech Academy of Sciences and her colleagues proposed a way that chemical reactions in the atmosphere could make phosphine without any help from life — and they’re not the first, although co-author Paul Rimmer of Cambridge University tells Inverse that he thinks their scenario is the “best hypothetical abiotic source for phosphine” so far.

Meanwhile, high in Venus’s atmosphere, something is absorbing huge amounts of ultraviolet radiation from the Sun. Over the last century, planetary scientists have suggested several chemical compounds, in different combinations, that could be absorbing the UV light, but no explanation quite fits, at least so far. And in a weirdly compelling coincidence, the shape of whatever’s absorbing the light, and the way it changes with the Venusian seasons, bears a striking resemblance to algal blooms in Earth’s oceans. Like the phosphine, it could be alien microbes busily doing photosynthesis, or it could be fascinating undiscovered chemistry.

And then there are the Mode 3 particles. These weirdly shaped particles in the lower cloud layers of Venus are less than a ten-thousandth of an inch wide, but that’s surprisingly large for particles floating in clouds. The Pioneer Venus mission discovered them in early 1971, when one of its instruments measured the tiny shadows of particles passing by. They’re not tiny spheres, but amorphous blobs, and some scientists wonder whether they might be cells living in the droplets of liquid that make up the clouds.

As incredible a discovery as that would be, the Mode 3 particles could also be an optical illusion; the result of overlapping shadows of round droplets, or a problem with the Pioneer Venus instrument’s calibration. They could also be grains of dust blown aloft from the dead surface of Venus, or something else entirely.

All of these mysteries could be clues pointing to alien life in the Venusian clouds – or they could be a stack of coincidences, which future astrobiologists will one day use as a cautionary tale. We just don’t know yet.

“There are far more unanswered questions about Venus than any other planet,” says Limaye.

A TALE OF TWO PLANETS

Venus is both the most and the least Earth-like planet we know of. It’s about the same size as our home world, and it’s also a rocky world, shrouded by an atmosphere, in the habitable zone of our Sun. But Venus is also a hellworld that rotates backwards, where temperatures on the ground could melt lead and the clouds rain sulfuric acid. But some scientists argue high above the deadly heat and crushing pressure of the surface, the acidic clouds actually aren’t so bad, that is if you’re a microbe evolved to like that sort of thing.

“Venus is often overlooked as a target for astrobiology,” Massachusetts Institute of Technology astrobiologist Janusz Petkowski tells Inverse. “This is an unfair assessment.” Petkowski and his colleagues recently published a paper in the journal Astrobiology presenting a case for a habitable niche in Venus’s clouds.

Once upon a time (almost 4 billion years ago, that is), the young planets Venus and Earth probably looked a lot alike. The fledgling Venus may even have had seas of liquid water, much like the environments where life probably emerged from chemistry on Earth. Researchers like Petkowski and Limaye argue that if Venus and Earth were similar during their youth, there’s no reason life couldn’t have emerged on Venus just like it did on Earth (it’s also plausible that the same thing was happening on Mars at around the same time).

But, as siblings sometimes do, the two planets took very different paths in their adolescent years. For various reasons, Venus’s atmosphere acted like a greenhouse, holding in heat until the seas boiled away and the clouds turned noxious and acidic. But that process took at least a hundred million years, and Petkowski, Limaye, and others are betting that some Venusian life may have evolved quickly enough to survive as the seas evaporated and the clouds got more and more acidic. If they’re right, then colonies of microbes could still be drifting in the upper layers of Venus’s atmosphere, where temperatures are more hospitable, clinging to droplets of fluid or tiny grains of dust that make up the clouds.

LIFE, UH, FINDS A WAY

“No life on Earth could actually survive in Venus’s clouds,” says Petkowski.” “But if we define habitability as an environment that allows any kind of organic chemistry to survive – maybe even life with different chemical composition and different biochemical solutions – then Venus’s clouds could be potentially habitable.”

The cloud layers of Venus’s upper atmosphere stay between freezing and boiling — exactly the right temperature range for life — but they’re made mostly of droplets of sulfuric acid, mingled with a few microscopically tiny droplets of water. No environment on Earth is remotely similar. But seeing how the scrappiest, stubbornest Earth life has adapted to milder versions of these challenges, astrobiologists can learn how life might adapt to the harsh conditions of Venus.

Here on Earth, for example, some microbes that live in acidic hot springs have found ways to neutralize the acid around them. Venus’s clouds are much more acidic than even the most caustic hot springs here on Earth, but given millions of years to adapt, it’s possible that microbes could keep pace with their changing environment. Petkowski and his colleagues suggest that multi-layered cell walls or acid-resistant membranes could also help microbes keep the acid out and the water in.

For now, that’s all speculation, but in recent lab experiments, Worcester Polytechnic Institute chemist Maxwell Seager and his colleagues found that some amino acids (chemical compounds that form the building blocks for proteins) are completely fine hanging out in a mixture of 98 percent sulfuric acid and 2 percent water. In previous experiments, the same team learned that nucleic acids (the molecules that store the genetic code) are also undaunted by super-acidic conditions.

That could be good news for life, but surviving the acid clouds is just one part of the challenge. Life — at least life as we know it — needs water to survive, and if there’s water in Venus’s clouds, it exists in the form of microscopic droplets, and even those are probably few and far between. In the driest places on Earth — carefully climate-controlled libraries — some resourceful microbes use nearby salt to pull just a few molecules of water out of the air. It’s not hard to imagine microbes on Venus doing something similar while clinging to a droplet of liquid in a cloud.

But could microbes spend their whole lives in the air? Some microbes here on Earth spend part of their life cycle in the clouds, but on Venus, sinking too deep into the haze below means a boiling death. Petkowski and colleagues say that resourceful microbes could lock themselves into armored balls called spores when their environments get too hot; inside the spore, a dormant microbe could wait until wind currents lift them back up to where things are cooler.

In other words, life finds a way. Or at least, it theoretically could. We need a lot more information to know for sure, or even to say how likely this scenario could be.

WILL WE EVER FIND A SMOKING GUN?

Upcoming missions to Venus may help answer some questions about what’s really going on in the sulfuric acid clouds: How much water is there? Are there organic molecules? Did Venus ever have liquid water on its surface? All of these are pieces of a much larger question: Could the clouds of Venus be habitable, even for a kind of life that we’ve never seen on Earth?

A commercial spaceflight company called Rocket Lab plans to launch its Venus Life Finder mission in December 2024. Venus Life Finder will look for organic molecules in the upper cloud layers. Finding these molecules won’t prove there’s life on Venus (despite the mission’s ambitious name), but it would show that the acidic clouds are home to the kind of chemistry that makes life work. This would be an encouraging sign.

NASA’s DAVINCI mission, which is planned for a 2029 launch, will study Venus’s atmosphere from orbit — and drop a probe into it. A couple of years later, in 2031, NASA’s VERITAS mission will study the planet’s surface and it’s interior. At around the same time, the European Space Agency’s EnVision mission will also use radar to study the interior of Venus from space.

All of these missions could help scientists understand whether Venus ever had liquid water on its surface, and how the planet’s atmosphere evolved over time (ratios of different chemical isotopes in a planet’s atmosphere can contain clues about its history). They may also help find explanations for the phosphine and even the mysterious UV absorber.

However, all of these missions are still years away even if everything goes according to plan. As JWST and Artemis have both shown us, it seldom does; they call it rocket science for a reason. And none of them will be capable of actually detecting life among the clouds of Venus , only clues about whether it could survive there. The only way to find real proof of life on Venus, according to researchers like Petkowski and Limaye, will be to scoop up a sample of the Venusian clouds and bring it home.

And that possibility is still decades away.

“It will take at least a couple of decades or longer, given the rate at which the previously selected missions are taking to actually be implemented,” says Limaye. “It will be a long time before we actually detect life elsewhere. It's not going to be a single experiment. It's going to take a lot of effort and different experiments and investigations and missions to determine.”

In the meantime, we can speculate, and scientists can find new ways to analyze the data they have. And we can all enjoy the possibility that our Solar System may be a lot wilder and a lot livelier than we thought.

{ https://www.inverse.com/ }

06-05-2024 om 17:36 geschreven door peter