In 2018, NASA mission planners selected the Jezero Crater as the future landing site of the Perseverance rover. This crater was a natural choice, as it was once an ancient lake bed, as evidenced by the delta fan at its western edge. On Earth, these features form in the presence of flowing water that gradually deposits sediment over time. Combined with the fact that the Jezero Crater’s delta feature is rich in clays, this makes the region a prime target to search for biosignatures – evidence of past (and maybe present) life on Mars!

In recent news, NASA announced that the Perseverance rover had reached the top of Jezero Crater’s rim at a location the science team calls “Lookout Hill.” The rover spent the previous three and a half months climbing the rim, covering a distance of 500 vertical meters (1,640 vertical feet) and making science observations along the way. Now that it has crested the rim, Perseverance can begin what the mission team calls its “Northern Rim” campaign. Over the next year, the rover is expected to drive 6.4 km (4 mi) and visit up to four sites of interest where it will obtain geological samples.

Since it landed in the Jezero Crater in February 2021, Perseverance has completed four science campaigns. This includes the “Crater Floor,” “Fan Front,” “Upper Fan,” and “Margin Unit” based on where the rover was obtaining samples from. During the first campaign, the rover visited features around its landing site – like the Máaz formation – where it obtained several rock and atmospheric samples, and some witness samples for contamination assessment. The two campaigns that followed saw the rover explore different sections of Jezero’s delta fan and obtain samples of rock and clay.

The fourth campaign, meanwhile, consisted of the rover examining marginal carbonate rocks that circle the upper edge of the Jezero Crater. The science team calls Perseverance’s fifth campaign the “Northern Rim” because its route covers the northern part of the southwestern section of Jezero’s rim. The site was selected so that the rover could explore a region of Mars, unlike anything it has investigated before. Ken Farley, a project scientist for Perseverance at Caltech, explained in a NASA press release:

“The Northern Rim campaign brings us completely new scientific riches as Perseverance roves into fundamentally new geology. It marks our transition from rocks that partially filled Jezero Crater when it was formed by a massive impact about 3.9 billion years ago to rocks from deep down inside Mars that were thrown upward to form the crater rim after impact. These rocks represent pieces of early Martian crust and are among the oldest rocks found anywhere in the solar system. Investigating them could help us understand what Mars — and our own planet — may have looked like in the beginning.”

Now that Perseverance has crested and moved on from Lookout Hill, the rover is heading to a rocky outcrop about 450 m (1,500 feet) on the other side of the rim known as “Witch Hazel Hill.” Said Candice Bedford, a Perseverance scientist from Purdue University:

“The campaign starts off with a bang because Witch Hazel Hill represents over 330 feet [~100 m] of layered outcrop, where each layer is like a page in the book of Martian history. As we drive down the hill, we will be going back in time, investigating the ancient environments of Mars recorded in the crater rim. Then, after a steep descent, we take our first turns of the wheel away from the crater rim toward ‘Lac de Charmes,’ about 2 miles [3.2 km] south.”

Located on the plains beyond the rim, the Lac de Charmes region is of interest to the mission team because it is less likely to have been affected by the impact that led to the Jezero Crater. Beyond that, the rover will travel about 1.6 km (1 mi) back up the rim to investigate an outcropping of blocks (megabreccia) that may be the remains of ancient bedrock broken by another impact. This was the Isidis impact, which occurred 3.9 billion years ago and led to the formation of the Isidis Planitia basin in the Northern Lowlands.

Investigating this site could provide valuable insight into a major surface-reshaping event that took place during the Noachian Period on Mars. This geological epoch saw extensive erosion by flowing water, as indicated by the many river valley networks dated to the period. It is also during the Noachian that the Tharsis Bulge is believed to have formed, indicating that Mars was still geologically active. As always, the ultimate goal is to find biosignatures from this “warmer, wetter” period that indicate that Mars could have had life (similar to Earth at the time).

The Perseverance science team also shared information on the rover, their science operations, and future plans at a media briefing on Thursday, December 12th, during the annual meeting of the American Geophysical Union (AGU) in Washington. As Steven Lee, the deputy project manager for the Perseverance mission at NASA’s Jet Propulsion Laboratory, said during the briefing:

“During the Jezero Crater rim climb, our rover drivers have done an amazing job negotiating some of the toughest terrain we’ve encountered since landing. They developed innovative approaches to overcome these challenges — even tried driving backward to see if it would help — and the rover has come through it all like a champ. Perseverance is ‘go’ for everything the science team wants to throw at it during this next science campaign.”

Further Reading: 

• NASA

{ https://www.universetoday.com/ }

15-12-2024 om 23:10 geschreven door peter  

Posted by Mark Thompson

NASA Thinks it Knows Why Ingenuity Crashed on Mars

NASA’s Ingenuity helicopter sent its final signals to Earth in the earlier part of the year. Engineers have been studying these and have started to piece together a picture of events that led up to its final flight. They concluded that data provided by the navigation system was inaccurate leading to a chain of events that caused its ultimate demise. One of the biggest problems it seems is that the terrain was smooth leading to a lack of landmarks during Flight 72.

Mars is the fourth planet from the Sun and is well known for its distinctive red colour. It’s surface is is covered in iron-oxide which is known by the more common name – rust. The planet is just over half the size of the Earth and has some fascinating geological features like Olympus Mons, the largest volcano in the Solar System. Valles Marineris is a canyon system which stretches thousands of kilometres and dwarfs the Grand Canyon. The atmosphere of the planet is mostly composed of carbon dioxide and currently incapable of supporting life. It’s not thought this has not always been the case and its missions like Mars 2020 that have helped to unravel the mysteries of the red planet. 

The Perseverance Rover and Ingenuity helicopter were both part of the Mars 2020 mission and have been exploring Mars since their launch in 2020 atop an Atlas V rocket. Ingenuity became the first robotic rotorcraft that undertook powered flight in the Martian atmosphere. The inaugural flight took place on 19 April 2021 the 1.8 kilogram drone took off under the power of two counter-rotating blades. The blades of the drone are 1.2m long, oversized by Earth standards but the atmosphere is only 1% as dense as Earth so larger than usual blades are needed. 

Flight 72 was scheduled for the 18th January this year and there was nothing special about it. The plan was a brief vertical hop to checkout the flight systems and to grab some photographs of the area. The flight data revealed it reached an altitude of 12 metres, took the images and was back on the surface after 32 seconds but had severed communications. After communications  was re-established, it was discovered that Ingenuity had sustained damage to its rotors. 

Now, almost a year after the incident, a team of engineers from NASA’s Jet Propulsion Laboratory have been analysing the data. Their findings will be published in the next few weeks however the team of engineers assert it was harder than expected to complete an accident investigation from 160 million kilometres. The faults lie in the navigation system that was designed to visually track surface features using a camera pointed at the round. The system worked during early flights over more textured terrain but as Ingenuity moved over the Jezero Crater, it began operating over featureless sand ripples. 

The navigation system was designed to provide estimates of the helicopter’s velocity, chiefly to enable it to land. The data revealed from Flight 72 revealed that the navigation system couldn’t find features to track. Images showed that the lack of features led to a harden than usual touchdown leading to a pitch and roll of the craft. The sudden change of attitude led to increase load on the rotors, beyond their designed limits leading to the structural damage. 

Even though Ingenuity will not be able to fly anymore it can still provide weather and avionics data to the Perseverance rover. It will help us to understand more about the weather in its vicinity but perhaps its greatest legacy are its hours of flight on an alien world. 

Source : 

• NASA Performs First Aircraft Accident Investigation on Another World

{ https://www.universetoday.com/ }

13-12-2024 om 18:36 geschreven door peter  

• READ MORE: Huge black hole 8,200 times the size of the Sun is discovered 

By WILIAM HUNTER

They are some of the universe's most unusual and fascinating objects.

And now a study suggests that black holes might be even stranger than we thought.

NASA's Chandra X-ray observatory has captured vast plasma jets from a supermassive black hole slamming into a mysterious object.

The researchers who made this bizarre discovery say they have no idea what this galactic speedbump might be or why it seems to act so strangely.

The hidden object lurks within the galaxy Centaurus A, an irregular swirl of gas and dust approximately 12 million light-years from Earth.

What makes Centaurus A so special is the supermassive black hole at its heart which shoots radiation and matter 40,000 light-years across the entire width of the galaxy.

Using the deepest X-ray images ever taken of the galaxy, the researchers found a V-shaped patch of bright emissions caused by the collision of these jets and some unknown object.

NASA says: 'While the researchers have ideas about what is happening, the identity of the object being blasted is a mystery because it is too distant for its details to be seen, even in images from the current most powerful telescopes.'

Scientists have made a baffling discovery as they spot an unknown object being battered by the plasma jet of a supermassive black hole (pictured) 

As black holes gather matter into an accretion disk, some of this is accelerated and shot out into space in the form of a vast beam of plasma and radiation (artist's impression)

When a star more than 20 times the size of our sun dies and explodes in a supernova, the remaining matter collapses down into an extremely dense object called a black hole.

These mysterious voids exert such a strong gravitational force that nothing, not even light, can escape their pull.

As matter and light fall into the black hole like water circling a plug hole, they form an enormous swirling ring called an accretion disk.

However, not all of that matter ends up falling beyond the point of no return known as the event horizon.

Instead, some of the matter gets accelerated along the black holes' powerful magnetic field lines and shot out of the poles and incredible speeds.

While scientists know roughly why these jets form, their near-relativistic speed and intense forces make much of their true nature a mystery.

Located relatively close to Earth, Centaurus A has long been the ideal place to observe these mysterious jets in action.

In previous studies, NASA has spotted a series of 'jet knots' within Centaurus A's massive plumes.

The galaxy Centaurus A (pictured) is 12 million light-years from Earth and is notable for the supermassive black hole at its heart which generated a 40,000-light-year plume of plasma

Scientists have previously spotted 'jet knots) which show up as bright spots of X-ray radiation in images 

Centaurus A: Key Facts

Size: 60,000 light-years in diameter

Mass: 1,000 billion solar masses

Distance from Earth: 12 million light-years

Discovered: 1826 

• • It is notable for its huge belt of dust and the supermassive black hole at its core which produces huge radiation jets. 
  • Centaurus A is the fifth brightest galaxy in the sky which makes it a great target for amateur astronomers.

These are massive areas of turbulence which showed up as bright spots in the X-ray spectrum.

But, in this latest study Dr David Bogensberger, an astrophysicist from the University of Michigan, and his co-authors found a knot which didn't match any of the usual patterns.

Dr Bogensberger and his co-authors write: 'Near the counterjet axis, we detected a source with an unusual morphology. We label it as C4.'

'It appears to have two streams of matter trailing away from it at two distinct angles, forming a ‘V’-like shape behind it.'

The arms of the V are at least about 700 light-years long - 140 times the distance from Earth to the nearest neighbouring star.

The V of strong X-ray radiation traily behind C4 are unusual since all other obstacles in the jet’s path only produce elliptical blobs.

NASA suggests that the mysterious object at the heart of this cosmic wake could be a massive star, either on its own or with a companion star.

The researchers believe that particles in the black hole jet could be colliding with the strong solar winds emitted by this star. 

If this were the case, the resulting turbulence would increase the density of the gas in the jet, igniting the X-ray emission seen within the Chandra images.

However, C4's unique structure raises some problems for this relatively simple explanation.

This study found an object known as C4 which had an unusual V-shaped wake stretching out behind it. This is totally different to the elliptical patterns usually produced by objects caught in a black hole's jet 

Scientists think that C4's unique shape might be the product of a massive star. As particles in the jet collide with solar wind from the star, this compresses the jet and ignites the bright X-ray radiation seen in these images

Read More

• Scientists discover a huge black hole in the Milky Way that's 33 times as massive as the Sun 

If there were an object in the jet, astronomers would expect to see an X-ray trail running roughly parallel to the jet's direction like the wake around a boat moving upstream.

The bottom arm of the V does match this picture, but the top arm is harder to explain since it is at a much larger angle to the jet.

That means, whatever this object is, it may have some very unusual properties which astronomers haven't spotted anywhere else in the universe.  

NASA says: 'Astronomers are trying to determine why C4 has this different post-contact appearance, but it could be related to the type of object that the jet is striking or how directly the jet is striking it.'

However, for now at least, the identity of this strange object will remain stubbornly mysterious.

BLACK HOLES HAVE A GRAVITATIONAL PULL SO STRONG NOT EVEN LIGHT CAN ESCAPE

Black holes are so dense and their gravitational pull is so strong that no form of radiation can escape them - not even light.

They act as intense sources of gravity which hoover up dust and gas around them. Their intense gravitational pull is thought to be what stars in galaxies orbit around.

How they are formed is still poorly understood. Astronomers believe they may form when a large cloud of gas up to 100,000 times bigger than the sun, collapses into a black hole.

Many of these black hole seeds then merge to form much larger supermassive black holes, which are found at the centre of every known massive galaxy.

Alternatively, a supermassive black hole seed could come from a giant star, about 100 times the sun's mass, that ultimately forms into a black hole after it runs out of fuel and collapses.

When these giant stars die, they also go 'supernova', a huge explosion that expels the matter from the outer layers of the star into deep space. 

Black hole blasting powerful jet directly imaged for the first-time ever!

{ https://www.dailymail.co.uk/ }

12-12-2024 om 22:14 geschreven door peter  

Posted by Brian Koberlein

Early Earth's Oceans of Magma Accelerated the Moon's Departure

The Earth and Moon have been locked in a gravitational dance for billions of years. Each day, as the Earth turns, the Moon tugs upon the oceans of the world, causing the rise and fall of tides. As a result, the Earth’s day gets a little bit longer, and the Moon gets a little more distant. The effect is small, but over geologic time it adds up. About 620 million years ago, a day on Earth was only 22 hours long, and the Moon was at least 10,000 km closer than it is now.

Evidence for this evolving dance in the geological record only goes back about two billion years. Beyond that, the Earth was so very different that there simply isn’t enough evidence to gather. So, instead, we must rely on computational models and our understanding of dynamics. We know that when the Earth formed, it had no large moon. Then, about 4.4 billion years ago, a Mars-sized protoplanet named Theia collided with our world to create the Earth-Moon system. What’s interesting is that most of the computer simulations for this collision generate a Moon that is much closer to the Earth than we’d expect. Early Earth didn’t have vast oceans, so there were no water tides to drive the Moon to a larger orbit. So how did the Moon get to its present distance?

A new study argues that back then the Earth did have tides, but they were made of lava, not water. Just after the Great Collision, Earth would have been covered in an ocean of hot lava. With the Moon so near, the lava would have experienced strong tides. Since lava is much denser than water, the effects of the tide would have been much greater. The Earth’s rotation would have slowed down much faster, and the Moon would quickly become more distant. Based on their simulations, the authors argue that the Moon’s distance would have increased by 25 Earth-radii in just 10,000 to 100,000 years. This would explain how the Moon moved towards its present distance range rather quickly.

The idea of tides on an ocean world also has implications for planets around other stars. Planets that form very close to their sun would be extremely hot, and many of them could have lava oceans for a billion years or more. Simulations of such worlds show that lava tides would accelerate the spin dynamics of such a world and could cause them to become tidally locked on a million-year timescale instead of a billion-year timescale. If this model is correct, it would have a significant impact on potentially habitable worlds. Most exoplanets orbit red dwarf stars, since red dwarfs make up about 75% of the stars in our galaxy. The habitable zone of red dwarfs is very close to the star, meaning that many of them would have begun as lava worlds. This would mean most potentially habitable worlds would have one side always facing the sun, while the other side is forever in the cold. Life on these worlds would be very different from what we see on Earth.

How Molten Magma Helped Transform Our Planet | Ancient Earth | BBC Earth Science

The Big Splash - Formation of the Moon

Reference: 

• Farhat, Mohammad, et al. “Tides on Lava Worlds: Application to Close-in Exoplanets and the Early Earth-Moon System.” arXiv preprint arXiv:2412.07285 (2024).

{ https://www.universetoday.com/ }

12-12-2024 om 17:13 geschreven door peter  

Mars Dust Storms Can Engulf The Entire Planet. A New Study Examines How

Today’s weather report on Mars: Windy with a chance of catastrophic dust storms blotting out the sky.

In a new study, planetary scientists at the University of Colorado Boulder have begun to unravel the factors that kick off major dust storms on Mars—weather events that sometimes engulf the entire planet in swirling grit. The team discovered that relatively warm and sunny days may help to trigger them.

Heshani Pieris, lead author of the study, said the findings are a first step toward forecasting extreme weather on Mars, just like scientists do on Earth.

“Dust storms have a significant effect on rovers and landers on Mars, not to mention what will happen during future crewed missions to Mars,” said Pieris, a graduate student at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder. “This dust is very light and sticks to everything.”

She will present the results Tuesday, Dec. 10 at the 2024 meeting of the American Geophysical Union in Washington.

To put dust storms under the magnifying glass, the researchers drew on real observations from NASA’s Mars Reconnaissance Orbiter satellite.

So far, they have identified weather patterns that may underly roughly two-thirds of the major dust storms on Mars. You won’t see Mars weather reporters standing in front of a green screen just yet, but it’s a step in the right direction, said study co-author Paul Hayne.

“We need to understand what causes some of the smaller or regional storms to grow into global-scale storms,” said Hayne, a researcher at LASP and associate professor at the Department of Astrophysical and Planetary Sciences. “We don’t even fully understand the basic physics of how dust storms start at the surface.”

This close-up image of a dust storm on Mars was acquired by the Mars Color Imager instrument on NASA’s Mars Reconnaissance Orbiter on Nov. 7, 2007, around 3 p.m. local time on Mars. Scientists working with NASA’s Curiosity rover, which is set to land on Mars on Aug. 5 PDT (Aug. 6 EDT), are monitoring Mars each day for similar small storms that could either drift over the landing site or stir up dust that moves as haze over the site. — NASA (larger image)

Dusty demise

Dust storms on Mars are something to behold.

Many begin as smaller storms that swirl around the ice caps at the planet’s north and south poles, usually during the second half of the Martian year. (A year on Mars lasts 687 Earth days). Those storms can grow at a furious pace, pressing toward the equator until they cover millions of square miles and last for days.

The 2015 film The Martian starring Matt Damon featured one such apocalyptic storm that knocked over a satellite dish and tossed around astronauts. The reality is less cinematic. Mars’ atmosphere is much thinner than Earth’s, so dust storms on the Red Planet can’t generate much force. But they can still be trouble.

In 2018, for example, a global dust storm buried the solar panels on NASA’s Opportunity rover under a layer of dust. The rover died not long after.

“Even though the wind pressure may not be enough to knock over equipment, these dust grains can build up a lot of speed and pelt astronauts and their equipment,” Hayne said.

Hot spells

In the current study, Pieris and Hayne set their sights on two weather patterns that tend to occur every year on Mars known as “A” and “C” storms.

The team pored over observations of Mars from the Mars Climate Sounder instrument aboard the Mars Reconnaissance Orbiter over eight Mars years (15 years on Earth). In particular, Pieris and Hayne looked for periods of unusual warmth—or weeks when more sunlight filtered through Mars’ thin atmosphere and baked the planet’s surface.

They discovered that roughly 68% of major storms on the planet were preceded by a sharp rise in temperatures at the surface. In other words, the planet heated up, then a few weeks later, conditions got dusty.

“It’s almost like Mars has to wait for the air to get clear enough to form a major dust storm,” Hayne said.

The team can’t prove that those balmy conditions actually cause the dust storms. But, Pieris said, similar phenomena trigger storms on Earth. During hot summers in Boulder, Colorado, for example, warm air near the ground can rise through the atmosphere, often forming those towering, gray clouds that signal rain.

“When you heat up the surface, the layer of atmosphere right above it becomes buoyant, and it can rise, taking dust with it,” Pieris said.

She and Hayne are now gathering observations from more recent years on Mars to continue to explore these explosive weather patterns. Eventually, they’d like to get to the point where they can look at live data coming from the Red Planet and predict what could happen in the weeks ahead.

“This study is not the end all be all of predicting storms on Mars,” Pieris said. “But we hope it’s a step in the right direction.”

VIDEOS

{ https://astrobiology.com/ }

11-12-2024 om 22:16 geschreven door peter  

Five UFO videos this week, are they alien, ai US drones or Chinese ai drones? UAP Sighting News.

Here are the top 5 most interesting videos of UFOs this week. Each are different, some with swarms, so watch and decide what is happening and can you predict the future outcomes of this? 

Scott C. Waring 

Full credit to NUFORC for reports at  https://nuforc.org/

I believe I may have discovered the purpose of the swarms of drones, God help us if I'm right. US Drone News.

Now I heard the swarms of drones were seen over Trumps favorite golf course for over three days and nights which makes me think...why? Who hates trump the most outside of the US? Easily one country over all does...the county he promised to put 25% taxes on all goods going out of China to US, and I believe the Chinese are behind these swarms. They must be radar resistant, which means they are plastic or 3d printed with some rubber radar resistant coating to absorb radar. They were seen over England, New York, Michigan, New Jersey and a few other locations. Read the tweet and tell me...am I wrong? Or...worse yet...am I right? If I'm right the virus could be waiting for a second drone spraying to become the catalyst of the virus, or the virus could have a built in genetic time to go off in 1 week, 1 month or even 1 years time. By then...everyone will forget about the drones. Because of a genetic timer, we cannot blame the drones, much like HAARP program that manipulates the weather and China uses it making it impossible to blame then on earthquakes (Japan-Chinas worst enemy at Fukushima), tidal waves, tornadoes, hurricanes and more. And China causes tens of billions of dollars in damage on such untraceable attacks. Ask yourself, what are the Chinese up to now? 

at 12/10/2024 01:56:00 PM 

{ https://www.ufosightingsdaily.com/ }

11-12-2024 om 18:41 geschreven door peter  

The orbits of the planets around the Sun have been the source for many a scientific debate. Their current orbital properties are well understood but the planetary orbits have evolved and changed since the formation of the Solar System. Planetary migrations have been the most prominent idea of recent decades suggesting that planetary interactions caused the young planets to migrate inwards or outwards from their original positions. Now a new theory suggests 2-50 Jupiter mass object passing through the Solar System could be the cause. 

The evolution of the orbits of the planets is a complex process. Initially the planets formed out of a rotating disk of gas and dust around the young hot Sun. The phenomenon of the conservation of angular momentum caused the material to form a plane leading to orbits that were circular and in the same plane. 

As the planets grew, interactions within the protoplanetary disk led to orbital migrations with planets moving inwards or outwards. There were gravitational interactions too that led to significant changes in the eccentricity and inclination, sometimes causing protoplanets to be ejected out of the solar system. Tidal forces from the Sun could also have altered the orbits. 

While protoplanet ejections are thought to have been fairly common as the Solar System was forming, on occasions celestial objects visited us. These objects seem to have been rare and provide a valuable insight into distant planetary systems. Oumuamua, was discovered in 2017 and was the first confirmed interstellar visitor. It exhibited an elongated shape and unusual acceleration, probably caused by outgassing or other non-gravitational forces. A paper recently published has suggested such an interstellar visitor could have driven changes in the orbits of our planetary cousins. 

The paper was authored by a team of scientists led by Garett Brown University of Toronto. They explore the nature of the eccentricity of the gas giants suggesting it is unlikely the current theories can explain observations. Instead they demonstrate that an object with between 2 to 50 times the mass of Jupiter passing through the Solar System was a more likely cause. Their paper explains that an object passing through with a perihelion distance (closest distance from Sun) of less than 20 astronomical units and a hyperbolic excess velocity less than 6km/s-¹ could explain observations.  

Their calculations suggest there is a 1 in 100 chance that an interstellar visitor could produce the orbits we see today, chances that are far better than other theories. Using simulations and approximate values for the properties of the visitor, the team conclude that the theory is the most plausible to date. 

Source :

• A substellar flyby that shaped the orbits of the giant planets

{ https://www.universetoday.com/ }

11-12-2024 om 18:20 geschreven door peter  

NASA's most powerful telescope detects something unexpected happening to the universe

• READ MORE: First breathtaking images from Euclid's 'cosmic atlas' are revealed

By WILIAM HUNTER

NASA's most powerful telescope has spotted something unexpected which could overturn our basic assumptions about the universe.

Using the James Webb Space Telescope (JWST), scientists from Johns Hopkins University have taken extremely accurate measurements of the distances between galaxies.

These observations reveal that the universe is expanding eight to 12 per cent faster than our current best theories predict.

This suggests that there may be some unknown force which explains why the universe is expanding faster now than it was billions of years ago.

First spotted by the Hubble Space Telescope in 1998, it was previously possible that this acceleration was caused by nothing more unusual than a telescope error.

However, using two years of JWST observations, the researchers have now shown that Hubble's shocking findings were not mistaken.

According to lead author and Nobel laureate Professor Adam Riess, this shows that our understanding of the birth of the universe could be totally wrong.

He says: 'It confirms the puzzling finding from the Hubble Space Telescope that we have been wrestling with for a decade - the universe is now expanding faster than our best theories can explain.'

Scientists have used the James Webb Space Telescope to confirm that the Universe really is accelerating up to 12 per cent faster than our best theories would suggest. Illustrated: the expansion of the Universe from the Big Bang (left) to the present day (right)

Scientists measured the distance between distant galaxies containing pulsing stars called Cepheid variables. Since these flash at a rate proportional to their brightness, they are considered the 'gold standard' for measuring interstellar distances. Pictured: NGC 5468, a galaxy located about 130 million light-years from Earth which is the furthest galaxy observed to contain Cepheid variables 

Professor Riess initially used the Hubble Space Telescope to measure the distance between a set of different galaxies.

This revealed that the Universe's expansion was accelerating at a rate of 72.8 km per second per megaparsec, a distance equal to 3.26 million light-years.

What made this result so surprising is that the conventional wisdom about the evolution of the Universe suggested this figure should only be 67-68 km/s/Mpc.

This had the shocking implication that the standard model of cosmology might be missing out on something vitally important, creating what astronomers call the 'Hubble tension'.

More than 25 years later, Professor Riess has now used NASA's biggest and highest-performing telescope to prove that his Nobel Prize-winning discovery had not been an error.

Using the JWST Reiss and his co-authors focussed on a set of galaxies containing pulsing stars called Cepheid variables.

These unique stars flash at a rate which is proportional to their brightness, or luminosity, which makes them the 'gold standard' for measuring interstellar distances.

Using the well-studied galaxy NGC 4258 as a reference point, the study covered a third of the Hubble Telescope's original galaxy sample.

The new study covered roughly a third of Hubble's full galaxy sample, using the known distance to a galaxy called NGC 4258 (pictured) as a reference point. This allowed for extremely accurate measurements of the distance between galaxies 

The first observations made by Hubble in 1998 showed that the galaxy's expansion was accelerating faster than the standard model would suggest. The standard model is the theory which explains the Big Bang, the cosmic microwave background (pictured), and the early formation of galaxies

What is the standard model of cosmology?

The standard model of cosmology is the conventional wisdom about the underlying physics of the universe.

Often called the Lambda-CDM theory, this suggests the universe has three major components: matter, dark matter, and dark energy.

This explains the existence and pattern of the cosmic microwave background, the lingering echo of the Big Bang, and the distribution of galaxies.

However, it doesn't align with new observations of the Universe's rapidly accelerating expansion.  

Although the sample size was smaller, the team managed to take measurements about four times as precise as the previous study.

In addition to Cepheid variables, the researchers also took measurements from carbon-rich stars and the brightest red supergiants across the same galaxies.

This allowed them to further cross-check their results to be absolutely certain their measurements were correct.  

Spiral galaxy NGC 628, located 32 million light-years away from Earth, is seen in an undated image from the James Webb Space Telescope. NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), and the PHANGS team/Handout via REUTERS/File Photo Purchase Licensing Rights

These new recordings revealed that the galaxies were accelerating away from each other at a rate of 72.6 km/s/Mpc - nearly identical to Hubble's measurements from the very same galaxies.

Professor Riess says: 'The discrepancy between the observed expansion rate of the universe and the predictions of the standard model suggests that our understanding of the universe may be incomplete.

'With two NASA flagship telescopes now confirming each other’s findings, we must take this [Hubble tension] problem very seriously—it’s a challenge but also an incredible opportunity to learn more about our universe.'

This implies that we might be missing something vitally important about the birth of the universe.

Siyang Li, a Johns Hopkins doctoral student and a study co-author says: 'The Webb results can be interpreted to suggest there may be a need to revise our model of the universe, although it is very difficult to pinpoint what this is at the moment.'

By measuring the same set of galaxies as Hubble (illustrated), the scientists confirmed that the universe was accelerating at a rate of 72.6 km per second per megaparsec, a distance equal to 3.26 million light-years. The standard model suggests an acceleration of just 67-68 km/s/Mpc 

The standard model explains the evolution of galaxies, the cosmic microwave background from the Big Bang, the abundance of chemical elements in the universe, and many other key observations based on the known laws of physics.

However, nothing that scientists have been able to observe explains why the Universe should be accelerating at such a rapid rate.

Scientists believe the regular matter we can see and interact with makes up just 4 per cent of the total universe.

The remaining 96 per cent of the universe is made up of dark matter, which makes up the missing mass in some galaxies, and dark energy.

Dark energy could make up as much as 69 per cent of the universe and might provide the force responsible for space's expansion.

However, with the nature of dark energy remaining a mystery, scientists are still no closer to resolving the Hubble tension than they were back in 1998.

Professor Reiss says: 'Yes, it appears there is something missing in our understanding of the universe.

'Our understanding of the universe contains a lot of ignorance about two elements - dark matter and dark energy.

'There are many hypotheses that involve dark matter, dark energy, dark radiation - for example, neutrinos (a type of ghostly subatomic particle) - or gravity itself having some exotic properties as possible explanations.'

In the future, Professor Reiss says scientists will need more observations to better understand this vital clue. 

Eventually, that might help scientists propose a theory which explains why our predictions and observations about the universe don't line up.

He adds: 'Is the mismatch at the lower end, four to five per cent, or the higher end, 10 to 12 per cent, of what the current data allows? Over what range of cosmic time is it present? These will further inform ideas.'

WHAT IS DARK ENERGY?

Dark energy is a phrase used by physicists to describe a mysterious 'something' that is causing unusual things to happen in the universe. 

The universe is full of matter and the attractive force of gravity pulls all matter together. 

Then came 1998 and the Hubble Space Telescope observations of very distant supernovae that showed that, a long time ago, the universe was actually expanding more slowly than it is today.

The universe is not only expanding, but it is expanding faster and faster as time goes by,' Dr Kathy Romer, scientist at the Dark Energy Survey told MailOnline, as illustrated in this Nasa graphic

So the expansion of the universe has not been slowing due to gravity, as everyone thought, it has been accelerating. 

No one expected this, no one knew how to explain it. But something was causing it.

'The universe is not only expanding, but it is expanding faster and faster as time goes by,' Dr Kathy Romer, scientist at the Dark Energy Survey told MailOnline.

'What we'd expect is that the expansion would get slower and slower as time goes by, because it has been nearly 14 billion years since the Big Bang.'

This illustration depicts NASA’s James Webb Space Telescope – the largest, most powerful, and most complex space science telescope ever built – fully unfolded in space.

(Credits: NASA/Adriana Manrique Gutierrez)

Depiction of Hubble Telescope in bright outer space. Elements of this image furnished by NASA.

(© dimazel – stock.adobe.com)

{ https://www.dailymail.co.uk/ }

10-12-2024 om 22:01 geschreven door peter  

Reuzenkaart van het heelal onthult: Einstein had weer gelijk

Door de donkere energie van het heelal in kaart te brengen, hebben astronomen een gigantische kaart gemaakt die een van Einsteins beroemdste theorieën aan de zwaarste test tot nu toe onderwerpt.

Een van de beroemdste theorieën van Albert Einstein is de algemene relativiteitstheorie uit 1915.

De theorie beschrijft hoe massieve objecten ruimte en tijd om zich heen krommen, wat weer invloed heeft op hoe objecten bewegen. Met andere woorden, ze vertelt ons iets over zwaartekracht.

De theorie wordt echter voortdurend op de proef gesteld.

Astrofysici hebben bijvoorbeeld verklaringen moeten vinden voor het feit dat het heelal steeds sneller uitdijt terwijl massieve objecten samenklonteren door de zwaartekracht.

Nu heeft de zwaartekrachttheorie haar grootste test tot nu toe doorstaan.

Een internationaal team van onderzoekers aan onder andere de Universiteit van Michigan en de Universiteit van Texas in de VS heeft gegevens geanalyseerd van het ruimteobservatorium Dark Energy Spectroscopic Instrument (DESI) in Arizona.

Het instrument bestaat uit 5000 robotjes die samen met een reeks lichtmeters terug kunnen kijken in de geschiedenis van het heelal door donkere energie te onderzoeken en de afstand tot miljoenen sterrenstelsels en quasars in kaart te brengen.

Einsteins theorie houdt stand

Met de huidige gegevens heeft het onderzoeksteam de verspreiding, groei en ontwikkeling van meer dan 5,7 miljoen sterrenstelsels in kaart gebracht over een periode van 11 miljard jaar – van de totale ouderdom van het heelal van 13,8 miljard jaar.

Volgens astronomen is het heelal georganiseerd in het zogeheten kosmische web.

Hier zijn sterrenstelsels en clusters van sterrenstelsels verdeeld in een netwerk van lange strengen van donkere materie en sterrenstelsels, zogeheten filamenten, waar bijna geen sterrenstelsels zijn.

In het kosmische web vormt donkere materie ongeveer 27 procent van de totale energie van het heelal, terwijl donkere energie, die ervoor zorgt dat het heelal uitdijt en in principe de zwaartekracht tegenwerkt, ongeveer 68 procent vormt.

Het onderzoeksteam gebruikte de algemene relativiteitstheorie om de groei van het kosmische web te voorspellen.

Ze zagen dat de manier waarop de zwaartekracht de sterrenstelsels samenklontert en de manier waarop het kosmische web zich in de loop van de tijd ontwikkelt, consistent is met de theorie van Einstein.

Als er zwaartekracht aan de vergelijking zou worden toegevoegd of eruit zou worden verwijderd, zou het heelal er niet zo uitzien als nu.

De resultaten verklaren ook een ontdekking van het DESI-instrument in april 2024.

Hierbij observeerden wetenschappers dat donkere energie in de loop van de tijd verandert en dat het heelal daarom niet statisch uitdijt.

Er waren zelfs aanwijzingen dat het effect van donkere energie afnam. Dit zou verband kunnen houden met zwaartekracht.

Een extra bevinding

Het huidige onderzoek wierp ook nieuw licht op een ander kosmisch mysterie: het neutrino.

Neutrino’s zijn een soort elementaire deeltjes die nogal ongrijpbaar zijn, omdat ze geen elektrische lading hebben en bijna geen massa. Daarom worden ze ook wel spookdeeltjes genoemd.

Eerder onderzoek heeft een ondergrens gevonden voor de massa van neutrino’s. Met de nieuwe DESI-gegevens konden onderzoekers de bovengrens van de massa van neutrino’s bepalen.

{ https://wibnet.nl/heelal }

10-12-2024 om 20:31 geschreven door peter  

Venus Has Never Been Habitable, New Study Suggests

Planetary researcher Tereza Constantinou and her colleagues at the University of Cambridge have examined the chemical composition of the Venusian atmosphere and inferred that the planet’s interior is too dry today for there ever to have been enough water for oceans to exist at its surface; instead, Venus has likely been a scorching, inhospitable world for its entire history.

This composite image, taken by JAXA’s Akatsuki spacecraft, shows Venus.

Image credit: JAXA / ISAS / DARTS / Damia Bouic.

From a distance, Venus and Earth look like siblings: it is almost identical in size and is a rocky planet like Earth.

But up close, Venus is more like an evil twin: it is covered with thick clouds of sulfuric acid, and its surface has a mean temperature close to 500 degrees Celsius.

Despite these extreme conditions, for decades, astronomers have been investigating whether Venus once had liquid oceans capable of supporting life, or whether some mysterious form of ‘aerial’ life exists in its thick clouds now.

“We won’t know for sure whether Venus can or did support life until we send probes at the end of this decade,” Constantinou said.

“But given it likely never had oceans, it is hard to imagine Venus ever having supported Earth-like life, which requires liquid water.”

When searching for life elsewhere in our galaxy, astronomers focus on planets orbiting their host stars in the habitable zone, where temperatures are such that liquid water can exist on the planet’s surface.

Venus provides a powerful limit on where this habitable zone lies around a star.

“Even though it’s the closest planet to us, Venus is important for exoplanet science, because it gives us a unique opportunity to explore a planet that evolved very differently to ours, right at the edge of the habitable zone,” Constantinou said.

The dichotomous climate pathways proposed for Venus.

Image credit: Constantinou et al., doi: 10.1038/s41550-024-02414-5.

There are two primary theories on how conditions on Venus may have evolved since its formation 4.6 billion years ago.

The first is that conditions on the surface of Venus were once temperate enough to support liquid water, but a runaway greenhouse effect caused by widespread volcanic activity caused the planet to get hotter and hotter.

The second theory is that Venus was born hot, and liquid water has never been able to condense at the surface.

“Both of those theories are based on climate models, but we wanted to take a different approach based on observations of Venus’ current atmospheric chemistry,” Constantinou said.

“To keep the Venusian atmosphere stable, then any chemicals being removed from the atmosphere should also be getting restored to it, since the planet’s interior and exterior are in constant chemical communication with one another.”

The researchers calculated the present destruction rate of water, carbon dioxide and carbonyl sulfide molecules in Venus’ atmosphere, which must be restored by volcanic gases to keep the atmosphere stable.

Volcanism, through its supply of gases to the atmosphere, provides a window into the interior of rocky planets like Venus.

As magma rises from the mantle to the surface, it releases gases from the deeper portions of the planet.

On Earth, volcanic eruptions are mostly steam, due to our planet’s water-rich interior.

But, based on the composition of the volcanic gases necessary to sustain the Venusian atmosphere, the scientists found that volcanic gases on Venus are at most six percent water.

These dry eruptions suggest that Venus’s interior, the source of the magma that releases volcanic gases, is also dehydrated.

At the end of this decade, NASA’s DAVINCI mission will be able to test and confirm whether Venus has always been a dry, inhospitable planet, with a series of flybys and a probe sent to the surface.

The results could help astronomers narrow their focus when searching for planets that can support life in orbit around other stars in the galaxy.

“If Venus was habitable in the past, it would mean other planets we have already found might also be habitable,” Constantinou said.

“Instruments like the NASA/ESA/CSA James Webb Space Telescope are best at studying the atmospheres of planets close to their host star, like Venus.”

“But if Venus was never habitable, then it makes Venus-like planets elsewhere less likely candidates for habitable conditions or life.

“We would have loved to find that Venus was once a planet much closer to our own, so it’s kind of sad in a way to find out that it wasn’t, but ultimately it’s more useful to focus the search on planets that are mostly likely to be able to support life — at least life as we know it.”

• The study was published this month in the journal Nature Astronomy.
• T. Constantinou et al. A dry Venusian interior constrained by atmospheric chemistry. Nat Astron, published online December 2, 2024; doi: 10.1038/s41550-024-02414-5
• This article is based on a press-release provided by the University of Cambridge.

{ https://www.sci.news/ }

09-12-2024 om 20:45 geschreven door peter  

EXCLUSIVE - I'm a professional asteroid hunter - and this is what NASA is not telling you about the space rocks on a collision course for Earth

• READ MORE: Incredible moment asteroid crashes into Earth's atmosphere

By WILIAM HUNTER

This week, an asteroid slammed into Earth's atmosphere and exploded in a ball of fire above Siberia.

From the time the space rock was spotted by NASA to the time it hit Earth, space agencies around the world had just seven hours to react.

Luckily for Earth, this asteroid was only 70cm across and burned up harmlessly in the air - but for asteroid hunter Franck Marchis, this was too close for comfort.

Dr Marchis, senior astronomer at the SETI Institute and founder of the UNISTELLAR citizen astronomer network, told MailOnline: 'If it had been slightly bigger, that would been a very different story.'

While institutes like NASA and the European Space Agency (ESA) keep a close watch for any space rocks that threaten Earth, there simply aren't enough people watching the sky to catch everything. 

If scientists want to save humanity from a potential 'city killer' asteroid we need years of warning, not a handful of hours.

The solution, according to Dr Marchis, is to enlist amateur astronomers to fill in the gaps left behind by the professionals.

Dr Marchis says: 'Asteroids can come at any moment towards Earth. Having eyes on the sky everywhere in the world allows us to track them.' 

Professional asteroid hunter Franck Marchis says that governmental space agencies like NASA and ESA can't protect Earth from an impending asteroid impact alone

Franck Marchis (pictured) senior astronomer at the SETI Institute and founder of UNISTELLAR, told MailOnline that the only way to protect Earth from asteroids is for civilians to spot the threats that NASA misses 

What's the risk of an asteroid hitting Earth? 

On Christmas Day, 2004, while most of us were busy opening presents and enjoying time with our families, Dr Marchis was facing down a potentially deadly threat.

NASA had spotted a large space rock, known as a Near-Earth Object (NEO), and sent out a call for astronomers to take a closer look. 

After taking measurements of the asteroid's course and calculating its orbit, Dr Marchis and other astronomers came to the sobering realisation that it was headed right for Earth.

At around 400m in diameter, the asteroid, known as 2004 MN4, was a true city killer capable of punching through the atmosphere and hitting the planet with devastating force.

To make matters worse, Dr Marchis predicted that there were only four to seven hours before impact.

He says: 'The community was freaked out, for several hours we had no idea if it was going to hit the planet or not.'

Thankfully, it turned out that the initial observations had been wrong and 2004 MN4 merely skimmed by the planet without colliding.

Just like the film 'Don't Look Up', on Christmas Day 2004, Dr Marchis detected an asteroid that was predicted to collide with Earth. However, unlike the film, Dr Marchis spotted the 400m-long space rock when there were only four hours before it was expected to hit 

However, for seven hours on Christmas Day, there were only about 400 people in the world who knew just how close Earth had come to total disaster.

He says: 'I think when you see something like that, you realise that this is possible and you realise the potential impact of it.'

Each day, the Earth is bombarded by an estimated 100 tonnes of material from space, most of which are no larger than a grain of dust and burn up harmlessly in Earth's atmosphere.

However, astronomers have discovered 36,765 NEOs, including more than 11,000 which are over 140m across and 868 larger than a kilometre.

Of those, 1,714 are on the 'risk list' meaning that there is a non-zero chance of a collision with Earth. 

With space around Earth so full of potential threats, near misses are not entirely uncommon.

Last year a 130m-wide space rock named 2019 OK travelling at 88,500 kmph (55,000 mph) passed within just 72,500 km (45,000 miles) of Earth - extraordinarily close in astronomical terms.

Nor do asteroids need to be as large as 2003 MN4 to cause absolute devastation.

In 2004, Dr Marchis detected the asteroid 400m-wide 2004 MN4. At the time, calculations suggested it may hit Earth within hours of its discovery 

The Chelyabinsk meteor (pictured) which injured over 1,600 and damaged over 7,000 buildings in 2013 was believed to be just 18m in diameter.

For instance, the Chelyabinsk meteor which injured over 1,600 and damaged over 7,000 buildings in 2013 was believed to be just 18m in diameter.

Dr Marchis says: 'An asteroid of over 120 metres will impact our planet every 10,000 years on average.

'This shows that, if we want our civilisation to last for a long period of time, we need to look around us and characterise those objects.'

How can we save Earth from a devastating asteroid impact?

After the Christmas Day scare, Dr Marchis says he realised that small groups of professionals simply weren't up to the task of defending the entire planet.

'There are multiple stations around the world, professional telescopes, that detect and characterise objects but most of them are located in the same area,' Dr Marchis says. 

'It means that if an asteroid is coming to us from over Japan or Russia there is nobody looking in this direction, so we still have what we call dark zones.'

The novel solution was that, instead of having a handful of massive advanced systems, you could fill the dark zones with small, cheap telescopes to watch the whole sky at once.

Dr Marchis' initial plan was to place a series of small satellite telescopes in orbit (pictured) to detect incoming asteroids. However, this was deemed too expensive 

Dr Marchis says: 'We quickly realised that having an entire worldwide array of telescopes capable of watching all of the sky all of the time would help.'

Back in 2014, Dr Marchis thought that the best way to do this would be to surround the planet with a network of orbiting telescope satellites.

However, before the days of reusable rockets, nobody was interested in funding a vast satellite constellation and Dr Marchis now calls the idea his 'sci-fi' project.

Unable to put his telescopes in space, Dr Marchis ultimately settled on the next best thing: putting them in as many homes around the world as physically possible.

In 2015, he founded UNISTELLAR which makes relatively cheap telescopes 'smart telescopes' which can track objects in space and share their measurements with a network of amateur astronomers.

These observations allow average civilians to light up the world's dark zones and keep a watchful eye on anything that could pose a threat to Earth.  

When NASA or ESA's wide-angle telescopes spot something bright and fast moving through the sky they send a notification to a database called the Minor Planets Centre.

Dr Marchis says: 'Based on about five or six observations they tell other people: "Hey, there is an asteroid coming to us and it could be potentially hazardous."

Instead of going to space, Dr Marchis founded Unistellar which sells telescopes (pictured) that automatically share data on the objects they observe with a network of amateur astronomers. This allows scientists to gather lots of observations of potentially hazardous objects

'Amateur astronomers including those in our network get this notification and use our telescopes to refine the observation.

'It's by combining all those eyes together that refines the predicted orbit of the asteroid and confirms whether it is an asteroid rather than a piece of rocket.'

In the case of spotting a dangerous asteroid, the impact will first be confirmed by NASA's Sentry and ESA's Meerkat prediction systems.

Then Dr Marchis and the other members of UNISTELLAR would bring their predictions to the UN's International Asteroid Warning Network to coordinate the response.

This was exactly what happened with the asteroid COWECP5 which dramatically exploded over Russia this week.

The asteroid was spotted by a NASA-funded telescope in Arizona about seven hours prior to impact.

Amateur astronomers in Japan and Australia then used their smaller telescopes to work out exactly where and when it would hit.

This time, it was determined that the space rock would burn up in the atmosphere so the issue was not escalated to the UN but, if it had been bigger, it would have been these citizen scientists' observations which determined the areas to be evacuated. 

The Earth frequently faces near misses from hazardous asteroids. This year four 'potentially hazardous' asteroids passed Earth within a 12-hour window. The largest was the 'city killer' asteroid 2002 NV16 which is taller than the Blackpool Tower 

The future of planetary defence 

However, if humanity is to survive into the future, we need to do more than just know when Earth is about to be hit by an asteroid - we need a way of stopping it.

'The good news is that, two years ago, we made an experiment showing that we can deflect an asteroid if we know well in advance that such an impact will happen,' Dr Marchis says.

'And that's changing a lot about how we think about this problem.'

The experiment Dr Marchis refers to is NASA's Double Asteroid Redirection Test (DART) which slammed a fast-moving satellite into the side of a distant asteroid.

Although the results will be confirmed in 2026 by ESA's Hera mission, the early results show that the asteroid was indeed bumped out of its orbit.

And, as the satellite collided with its target, it was telescopes in the UNISTELLAR network that recorded the impact as it happened.

These observations provided the first images of the plumes of dust and debris caused by the collision which showed that the $324.5 million (£253.5 million) mission had been a success.

NASA's DART mission used a small fast-moving satellite to slam into a massive asteroid. This test showed that it is possible to knock an asteroid out of a collision course with Earth 

It was even the hard work of citizen scientists which provided the data that proved humanity really could push a dangerous asteroid out of the way.

Dr Marchis says that the goal is now to expand the UNISTELLAR network so that amateur astronomers can start to identify any asteroids that could pose a threat.

He says: 'What we need to do is map the entire surroundings of Earth to find all those bodies 120m or larger because, as soon as we know that one of them could impact our planet, we just have to send a spacecraft over to deflect it.

'We do more observations in a year now than we have done over the past 200 years but we could still do better.'

For example, there are still vast dark zones over the developing countries where Earth just can't see what is coming its way.

Dr Marchis says that the only solution is to either 'win the lottery' to fund his satellite telescopes or get more amateur astronomers involved in planetary defence.

He concludes: 'If people like astronomy or if they want to do something more meaningful in their life they should really look at what we do in citizen science.

'This is a movement which is going to change the way we progress as a civilisation and UNISTELLAR is proof that every human can make remarkable discoveries that will one day change humanity.'

{ https://www.dailymail.co.uk/ }

08-12-2024 om 23:26 geschreven door peter  

The Artemis moon landings are delayed again due to technical difficulties. This time, the problem is with the Orion spacecraft heat shield. NASA administrator Bill Nelson announced that the new landing dates are in April of 2026 for Artemis II and sometime in 2027 for the first human landing during the Artemis III mission.

The difficulties the Artemis program faces stem from the complexity of the hardware and trajectories needed to take astronauts to the Moon according to Nelson. “The Artemis campaign is the most daring, technically challenging, collaborative, international endeavor humanity has ever set out to do,” said Nelson. He pointed out that the mission has made a lot of progress. However, there’s more work to be done, in particular on the Orion life support systems. Artemis II is next up in early 2026. It will be a test flight to demonstrate the viability of all the systems, said Nelson. “We need to get this next test flight right. That’s how the Artemis campaign succeeds.”

Making a safe return through Earth’s atmosphere is a vital part of the mission. After Orion came back from its Artemis 1 mission in November 2022, engineers noticed issues with the heat shield. They figured out that gases generated inside the heat shield didn’t vent properly. That caused cracks in the shield and triggered an investigation. The decision to delay the Artemis II test flight came after that investigation. This allows NASA engineers to work with the heat shield currently attached to the Orion capsule for the April 2026 flight. In addition, they’re studying the re-entry process to avoid future problems with the shield. 

Artemis II to the Moon

As we all know, the Artemis program will allow long-term exploration of the Moon. The April 2026 mission is a test flight that will orbit, but not land, and then return to Earth. The idea is to test all the spacecraft’s systems with astronauts on board.

The Orion spacecraft is the crew’s living quarters and lab, all in one. It’s built to carry four astronauts from Earth to space and ultimately to the Moon. It makes sense that this “home away from home” has to be shielded from pretty much anything that space—and Earth’s atmosphere—can throw at the capsule. This includes the ultrahot trip through our atmosphere on the return trip. At times, Orion experiences temperatures up to 2700 C (5000 F), which could harm the capsule if not for the shielding. So, the shield is a life-saver.

When Orion first encountered the heat shield problem, engineers determined that heating rates increased during the spaceship’s planned “dips” into the atmosphere. It was performing a skip guidance entry technique. Heat built up inside the heat shield’s material and gases accumulated. Eventually, that cracked areas in the outer layer of the shield and blew some of it off to space. It turns out that if astronauts had been aboard, they would not have been affected. However, now that engineers understand what occurred, they can enhance the heat shield material to make sure it doesn’t happen again. In addition, the mission plan will be altered to change how far the capsule flies between atmospheric re-entry and eventual landing.

Upgrading Mission Plans

The extended time until the April 2026 and mid-2027 Artemis missions will allow improvements to the capsule and launch systems. For example, engineers can give more attention to environmental and life support systems. This is particularly important for the Artemis III mission. It will launch on top of a Space Launch System rocket into Earth orbit. Once there, the mission will perform a translunar injection to send it to lunar space.

Not only will it carry astronauts to the Moon, but they will land in the south polar region using a SpaceX landing system. That 30-day mission will require at least two crew members to spend a week at the pole collecting samples, doing site photography, and measuring conditions there.

Artemis III will be the first time anyone has set foot on the Moon since the last Apollo mission in December 1972. The entire Artemis program aims at providing long-term habitation and study of Earth’s nearest neighbor in space. To that end, NASA has been studying several interesting landing spots at the pole.

Eventually, there will be an orbiting lunar station, plus habitats on the surface and regular trips between. NASA and other agencies expect that lunar explorers will be spending their time studying the surface and geology of the Moon, plus determining what resources are available for long-term exploration and habitation. However, given the pace of the program, those next developments probably won’t take place until the 2030s.

For More Information

• NASA Identifies Cause of Artemis I Orion Heat Shield Chart Loss
• As Artemis Moves Forward, NASA Picks SpaceX to Land Next Americans on Moon
  Artemis II
• Artemis III: NASA’s First Human Mission to the Lunar South Pole

{ https://www.universetoday.com/ }

07-12-2024 om 23:28 geschreven door peter  

At left: Steel is seen to corrode into siderite (FeCO3) when immersed in subcritical liquid carbon dioxide (LCO2). At right: Samples of albite (a plagioclase feldspar) and a sandstone core are observed to form red rhodochrosite (MnCO3) when exposed to supercritical CO2 in the presence of a water solution with potassium chloride and manganese chloride, with particularly strong reaction near the interface of the two solutions. In both experiments, water saturation is provided by floating LCO2 on the water. Under the lower pressure conditions characteristic of early Mars, the water would float on the LCO2.

Credits:Photos courtesy of Todd Schaef/PNNL (left) and Earl Mattson/Mattson Hydrology (right).

Most people will think of a dry arid landscape when they think of Mars. When seen from orbit, dry river channels and lake-beds can be seen along with mineral deposits thought to be the created in the presence of liquid water. A team of researches now suggest that liquid carbon dioxide could also explain the features seen. On Earth, a process known as carbon sequestration liquefies CO2 which is buried underground. There are a number of mechanisms that could explain the liquid CO2 underground the researchers suggest.

Mars is often referred to as the ‘red planet’ due to its visual appearance. It’s the fourth planet from the Sun and has been a real focus for exploration and research for decades. The red colour is caused by iron oxide (rust) on its surface which can often be lifted up into the atmosphere by the Martian winds giving stunning pink skies. It’s just over half the size of the Earth, has a thin atmosphere mostly made of carbon dioxide and a surface composed of deserts and volcanoes like Olympus Mons. One of the key focusses of the exploration on Mars has been to establish whether the conditions are suitable for life, have been suitable in the past or whether liquid water exists on the surface. 

The presence of dry riverbeds and lake beds points to a surface that had liquid flowing long ago. Quite what that liquid is has been the cause for debate. Observations of minerals from orbit and from more direct analysis on the surface, suggest that the liquid was just water. However a team of researchers have published a paper in Nature Geoscience that suggests otherwise. They explain that water is only one of two possible liquids that could have existed on ancient Mars. The other is liquid carbon dioxide or CO2. Given the atmospheric conditions it may have been more likely and easier for CO2 in the atmosphere to condense into a liquid than for surface ice to melt into water. 

It has been the general consensus that the minerals point to liquid water. The paper suggests that processes like carbon sequestration, liquid CO2 buried underground can alter the composition of minerals even faster than water can. Lead author Michael Hecht, research scientist at MIT’s Haystack Observatory said “Understanding how sufficient liquid water was able to flow on early Mars to explain the morphology and mineralogy we see today is probably the greatest unsettled question of Mars science. There is likely no one right answer, and we are merely suggesting another possible piece of the puzzle.”

The paper explores our current understanding of the Martian atmosphere and combine it with the carbon sequestration research to conclude that the processes do support the evidence and mineralogy seen on Mars. They note however that this proposal does not suggest all Martian surface liquid was CO2 but rather there could have been a combination of the two.

They explain that liquid CO2 on the surface of Mars could exist as a stable surface liquid, as melted CO2 under CO2 ice or in subsurface reservoirs. Which actually took place would have dependent entirely on the distribution of CO2 at the time and the surface conditions too. The paper acknowledges that further testing is required under more realistic Martian conditions to test whether the same processes still occur. 

Source : 

• Liquid on Mars was not necessarily all water

Exploring Martian Geology and Habitability through Mineralogy

Curiosity Mining Minerals On Planet Mars

{ https://www.universetoday.com/ }

07-12-2024 om 22:16 geschreven door peter  

Humans on Mars could conduct far better science than any machine

Related: 

• NASA establishes 'Moon to Mars' office to help get astronauts to Red Planet

"Our partnerships with industry, academia, and the international community are helping NASA define an architecture that empowers us to boldly explore the moon, Mars, and beyond," Merancy explains.

Tale of the tiger team

Arguably, the science conducted on the surface of Mars by astronauts will have the most impact on the scope and scale of that architecture. Therefore, deciding on science priorities warrant early attention. 

Recent history demonstrates the issue of shoe-horning in science tasks for astronauts too late.

That is a central message from a recent study for the Mars Exploration Program Analysis Group (MEPAG), one that suggests how and where on the Red Planet humans can maximize exploration and science output. 

A MEPAG Tiger Team on Mars Human-Mission Science Objectives was led by Bruce Jakosky, a senior research scientist at the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. Their report was transmitted to NASA late last year.

Proactive, not reactive

"I think the real value of this report is if we can get NASA to pay attention," Jakosky told Space.com in an exclusive interview. "We see a lot of work going on in planning the architecture for human Mars missions. But science isn't on the table at all. My goal as chair of the Tiger Team is trying to get science into the discussion," he said.

Fitting science in around the edges is not the way to do world class science, Jakosky said. NASA needs to be proactive, not reactive in incorporating science, he said.

NASA's Apollo program of the 1960s into the early 1970s, noted Jakosky, had scientists, engineers, and astronauts working hand-in-hand, shoulder to shoulder to make sure science was done.

"And that's something that I don't think we see today in Artemis or in Mars," Jakosky said. "It's got to be an iterative process in order to make sure that the science and the engineering will work together," he said.

Science-based landing sites

Jim Head, a noted planetary researcher at Brown University, was a member of the Tiger Team report group. 

"NASA is currently updating the objectives for the Moon-to-Mars initiative with the strategy of 'architect from the right/execute from the left,'" Head said. That translates into, he added, "work backwards from the defined goal to establish the complete set of elements that will be required for success. Execute development of all elements in regular fashion, integrating as you move right according to the established architecture."

Head said that the MEPAG Tiger Team report was designed to be a part of NASA strategy, in that the group considered things like the optimum science-based Mars landing sites, the types of activities and stay-times required to accomplish goals and objectives, and potential robotic partnerships. 

"These types of considerations provide significant insights into feed-forward for the lunar component of NASA's Moon-to-Mars initiative, the Artemis phase," Head said.

Real-time interaction and adaptability 

Mars holds many clues to early solar system history and how terrestrial planets sustain habitats and life, said Bethany Ehlmann, a member the Tiger Team report group. She is a professor of planetary science at the California Institute of Technology (Caltech) and director of the Keck Institute for Space Studies in Pasadena, California.

For many types of geologic science, especially those involving lots of interaction with terrain like sample collection or deep coring, Ehlmann said that human capabilities are "uniquely enabling" because of real-time interaction and adaptability. 

"Humans on an EVA activity can accomplish in a few hours data acquisitions and sample collections that have taken rovers years," Ehlmann told Space.com. "With NASA's Moon-Mars initiative underway, it is important to think about what supporting instruments and technologies need to be developed now to equip our astronauts for doing outstanding science at Mars."

Ehlmann flags the reference missions called out in the study report that exemplify a range of possibilities, like astronauts investigating icy locales, accessing cliffs, exploring higher altitudes on Mars or having expeditions investigate caves. 

Those example cases underscore how individual, specific missions can achieve high-value science. 

Catalyze discussion

Jakosky as the Tiger Team chair notes that the list of cases called out in the report do not represent all potential missions, but "should serve to catalyze discussions within and between the science and exploration communities." 

Missions suggested included projected astronaut treks to Utopia Planitia, Valles Marineris, as well as Cerberus Fossae.

"Any landing site is going to provide spectacular science results. I think that's clear," Jakosky said. "Mars is a very diverse, geologically complex planet. One site isn't going to tell us everything we want to know about Mars."

One scenario involves crews going au naturel on Mars. That is subsurface study of natural caves — with many Mars caves already previously spotted. 

There's need to characterize the habitability conditions of a cave environment, be it the availability of water, energy sources and chemical potential. But also to determine if signatures of life are present in the cave environment, the report adds.

Human explorers could land near a target cave and remain within the habitat for much or most of the mission. They would teleoperate sample retrieving robots deployed to a cave floor. Doing so would eliminate the operations time lag compared to running a robotic investigation from Earth, "a multiple orders of magnitude decrease in decision time," says the report.

Why humans on Mars? 

The report spells out how humans can advance a valuable palette of science objectives at the Red Planet. Clearly, crews can conduct on-the-spot field measurements, execute local area mapping, and gain, below their boots, subsurface access. 

Selection of the highest value samples for return from the surface, subsurface, and atmosphere and getting those specimens into labs on Earth is crucial, the report explains.

First of all, explorers on Mars can emplace local and regional networks of info-gathering devices to capture processes operating on Mars during and between missions. 

From orbit or on the surface of Mars, teleoperating robotic assets as precursors to human struts across Mars can probe sites out-of-reach of a human landing site, or to assess a rich diversity of terrains and habitats.

Back here on Earth, there's need for ground controllers to operate the infrastructure needed to ensure human safety and efficient operations at Mars. It's also vital to loop in the enhanced capabilities for doing science thanks to teams of on-the-Earth specialists.

High-priority science

One key signal from the study is site selection to do science with humans at Mars. 

"Given the complexity of Mars' evolutionary history and the tremendous diversity of environments on Mars, no single site can address all of the high-priority science goals," the report stresses.

A central study finding is that vital science can be accomplished by humans on Mars "that would be much harder or impossible to do with robotic spacecraft; the capabilities of human missions have the potential to change both the objectives and the priorities — and can definitely accelerate the pace — for Mars scientific exploration."

As for science work on Mars, the Tiger Team flagged a trio of high-level objectives:

• Astrobiology - Determine if life ever developed on Mars and the nature of habitability;
• Climate and volatiles – Unravel the processes and history of water and climate change on Mars; and
• Geology/Geophysics/Geochemistry - Understand the physical record of planetary evolution from planetary formation until today and the processes driving the evolution of the surface, crust, and interior of Mars

"What sets Mars apart from the rest of the solar system is the potential for life, the history of water, and the nature of the geological processes and similarities to Earth," said Jakosky. "Secondly, it is the relative closeness of Mars and the relative ease with which we can explore it," he said.

Community input

Very familiar with the report findings is Scott Hubbard, a former director of the NASA Ames Research Center, now an affiliate in the Department of Aeronautics and Astronautics at Stanford University. 

Hubbard served as NASA's first Mars exploration program director in 2000, earning him the title of "Mars Czar" as he restructured the space agency's Mars program in the wake of several failures to explore the planet.

In Hubbard's view, the MEPAG Tiger Team report is an "excellent example of science objectives-based human exploration goals for Mars," Hubbard told Space.com. 

Hubbard said it is his hope that both NASA and the forthcoming National Academies study will utilize the Tiger Team report as "important community input."

The full text of the "Report Of MEPAG Tiger Team On Mars Human-Mission Science Objectives" can be read online.

{ https://www.space.com/ }

06-12-2024 om 22:32 geschreven door peter  

06-12-2024 om 21:17 geschreven door peter  

Water is een cruciaal ingrediënt voor het ontstaan van leven op andere planeten, net als op Aarde, en dan het liefst in een waterkringloop waarbij het goedje in vloeibare vorm bij een aangename temperatuur rondstroomt. Australische wetenschappers waren dan ook erg enthousiast toen ze in een beroemde Marsmeteoriet oeroud bewijs vonden van waterhoudende vloeistoffen.

De onderzoekers uit Perth hebben mogelijk het oudste directe bewijs van heet water op Mars gevonden. De ontdekking toont aan dat de rode planeet in een ver verleden leefbaar moet zijn geweest. Het team bestudeerde een zeldzaam zirkoonkorreltje van 4,45 miljard jaar oud, afkomstig uit de beroemde Marsmeteoriet NWA7034, beter bekend als Black Beauty.

Zirkoon
Het mineraal zirkoon is een zirkonium-silicaat met de molecuulformule ZrSiO4. De natuurlijke kleur van zirkoon varieert van kleurloos, goudgeel en rood tot bruin. Het mineraal wordt vaak verward met de synthetische edelsteen zirkonia, een geliefde imitatie van diamant, maar schijn bedriegt. Zirkonen zijn bijzonder goed bestand tegen verwering. Ze bevatten kleine hoeveelheden radioactieve isotopen van uranium en thorium, die op den duur vervallen tot een isotoop van lood. Door de verhoudingen van deze isotopen te bepalen is het mogelijk om de kristallisatietijd van het kristal te bepalen, en daarmee de ouderdom van het gesteente waarin het zich bevindt.

4,45 miljard jaar oude sporen
In het piepkleine korreltje vonden de onderzoekers oeroud bewijs van geochemische ‘vingerafdrukken’ van waterhoudende vloeistoffen, zo schrijven ze in hun studie. Volgens onderzoeker Aaron Cavosie geeft deze ontdekking de mensheid nieuwe inzichten in de hydrothermale systemen van Mars en de mogelijkheid dat de planeet vroeger leefbaar was. “Met behulp van nanogeochemie hebben we bewijs gevonden van heet water op Mars, zo’n 4,45 miljard jaar geleden”, maakt de onderzoeker duidelijk. “Hydrothermale systemen speelden een cruciale rol in het ontstaan van leven op aarde. Ons onderzoek laat zien dat ook onze buurplaneet Mars water had tijdens de vroege vorming van zijn korst – een essentiële voorwaarde voor een leefbare omgeving.”

Nanogeochemie
Door middel van hypermoderne beeldvormingstechnieken en spectroscopie op nanoschaal ontdekte het team patronen van elementen zoals ijzer, aluminium, yttrium en natrium in het zirkoon. Deze elementen zijn indertijd aan het mineraal toegevoegd tijdens de vorming van het kristal. Dit wijst erop dat er water aanwezig was op de rode planeet tijdens deze periode van vroege magmatische activiteit. Cavosie legt uit dat het water rondspoot op een moment in de planetaire geschiedenis, toen gigantische meteorietinslagen het oppervlak van Mars geselden en ontwrichtten. Dit spectaculaire proces vond plaats in de vroege Pre-Noachiaanse periode – een Martiaans tijdsgewricht meer dan 4,1 miljard jaar geleden.

Schokbestendig korreltje
Een eerder onderzoek in 2022 van hetzelfde zirkoonkorreltje toonde aan dat het een meteorietinslag had doorstaan. Dat was een unieke vondst. Tot nu toe is het de eerste en enige bekende ‘geschokte’ zirkoon van Mars. “Door onze bevindingen zijn we een flinke stap verder gekomen in onze kennis over het vroege Mars”, vertelt Cavosie. “We hebben nu duidelijke aanwijzingen van waterhoudende vloeistoffen uit de tijd dat het korreltje zich vormde. We kunnen de geochemische markers van water in de oudste bekende korst van Mars nu aanwijzen en hierop kunnen we verder bouwen in onze vervolgonderzoeken.”

Deze ontdekking geeft een fascinerend kijkje in de vroege geschiedenis van Mars en levert nieuw bewijs dat onze buurplaneet ooit omstandigheden kende die vergelijkbaar waren met een jonge versie van de Aarde.

Bronmateriaal

• "Zircon trace element evidence for early hydrothermal activity on Mars" - Science Advances
• Afbeelding bovenaan dit artikel: Kindel Media

{ https://scientias.nl/ }

06-12-2024 om 00:38 geschreven door peter  

700 miljoen jaar geleden veranderde de Aarde in een gigantische ijsbal. Eindelijk weten onderzoekers waarom

Jeannette Kras

Je hebt ijstijden en ijstijden en die van ruim 700 miljoen jaar geleden was me er eentje. De Aarde veranderde in één grote ijzige bol, zelfs de oceanen waren dichtgevroren. Tot nu toe begrepen onderzoekers niet goed hoe dat kon, maar nu hebben ze een verklaring: de vulkanen stootten extreem weinig CO2 uit.

“Stel je voor dat de Aarde compleet bevroren is, want dat is wat er zo’n 700 miljoen jaar geleden gewoon is gebeurd. De planeet was bedekt met ijs van de polen tot de evenaar en de temperaturen doken naar beneden”, zegt hoofdonderzoeker Adriana Dutkiewicz. “Wat dit heeft veroorzaakt, was tot nu toe echter een open vraag.”

Maar ze denkt dat het mysterie van de zogenoemde Sneeuwbalaarde nu is opgelost. “Waarschijnlijk was er een historisch lage uitstoot van vulkanische CO2 in combinatie met de verwering van een enorme berg vulkanisch gesteente in wat nu Canada heet, een proces waarbij de basaltstenen CO2 uit de atmosfeer absorberen.” Dat werkt als volgt: regen slaat CO2 op uit de lucht. Die regen reageert met het verpulverde basalt, die de CO2 opslaat.

Inspiratie uit het zuiden van Australië
De Australische geologen werden geïnspireerd door overblijfselen uit de ijstijd, die geweldig goed te zien zijn in de Flinders Ranges in Zuid-Australië. Een recente trip daarheen, bracht de wetenschappers op het idee om met behulp van een supercomputer van de University of Sydney tektonische plaatmodellen te bestuderen om te achterhalen wat de oorzaak is van de extreem lange en hevige ijstijd. De studie helpt bovendien om de natuurlijke thermostaat van de Aarde beter te begrijpen, die voorkomt dat onze planeet oververhit raakt. Het toont ook aan hoe gevoelig ons klimaat is voor de hoeveelheid CO2 in de atmosfeer.

Aan de slag met de computer
De extreme ijstijd duurde van ongeveer 717 tot 550 miljoen jaar geleden. In die tijd bestond er geen complex leven. “Er zijn verschillende oorzaken genoemd voor het begin en het einde van deze ijstijd, maar het meest mysterieuze is waarom hij tientallen miljoenen jaren duurde, een lengte die wij ons nauwelijks kunnen voorstellen”, aldus Dutkiewicz.

De onderzoekers wendden zich tot een tektonisch plaatmodel dat de evolutie van continenten en oceanen laat zien in de periode na het uiteenvallen van supercontinent Rodina. Dat verbonden ze met een computermodel dat de CO2-ontgassing van onderwatervulkanen berekende langs de breuklijnen waar de tektonische platen uit elkaar drijven en nieuwe oceaanbodem ontstaat.

Kalme vulkanen
Zo zagen ze al snel dat het begin van de ijstijd precies overeenkwam met een ongezien dieptepunt aan vulkanische CO2-uitstoot. Daarbij bleef de uitstroom van CO2 relatief laag gedurende de hele ijstijd. “In die tijd waren er geen meercellige dieren of landplanten op Aarde. De broeikasgasconcentratie in de atmosfeer werd bijna volledig bepaald door de CO2-uitstoot van vulkanen en de CO2-opslag van verpulverd vulkanisch gesteente.”

Met andere woorden, vulkanen bepaalden het klimaat op Aarde. “We denken dat de ijstijd begon door een dubbele klap: een opschudding van de tektonische platen bracht de ontgassing van vulkanen tot een minimum, terwijl tegelijkertijd een vulkanische provincie in Canada begon te eroderen. Die sloeg dus een enorme berg CO2 op”, legt professor Dietmar Müller van de University of Sydney uit. “Het gevolg was dat het CO2-niveau in de atmosfeer zo laag werd dat de ijstijd begon. De schatting is dat dit gebeurt bij minder dan 200 CO2-deeltjes per miljoen, minder dan de helft van wat er nu in de atmosfeer zit.”

De toekomst
Het onderzoek roept interessante vragen op over de toekomst van de Aarde. Volgens een recente theorie zou onze planeet in de komende 250 miljoen jaar kunnen evolueren tot Pangea Ultima, een supercontinent, dat zo heet is dat zoogdieren mogelijk uitsterven.
De CO2-uitstoot van vulkanen wordt echter op de lange termijn minder is de verwachting, dus misschien verandert Pangea Ultima ook weer in een ijsbal. “Wat de toekomst ook brengt, het is belangrijk om te weten dat geologische klimaatverandering, zoals we die hier beschrijven, extreem langzaam gaat. Volgens de NASA gaat door mensen veroorzaakte klimaatverandering tien keer sneller dan we tot nu toe hebben gezien”, klinkt het tot besluit.

Bronmateriaal

• "Duration of Sturtian 'Snowball Earth' glaciation linked to exceptionally low mid-ocean ridge outgassing" - Geology
  
• Afbeelding bovenaan dit artikel: NASA

VIDEO'S

How Snowball Earth Leveled Mountains and Created the Great Unconformity

From Ice Age to Snowball Earth: Our Frozen Planet's History

How Volcanoes Froze the Earth (Twice)

{ https://scientias.nl/ }

06-12-2024 om 00:21 geschreven door peter  

New details about impact of massive asteroid that hit the US revealed

• READ MORE:  Incredible moment asteroid crashes into Earth's atmosphere

By ELLYN LAPOINTE FOR DAILYMAIL.COM

Scientists have revealed new details about the impact of a massive asteroid that hit the US roughly 35 million years ago. 

The asteroid, between three and five miles wide, created a giant 25-mile-wide crater in what now lies beneath Chesapeake Bay, with the center located at the southern end of Northampton County near Cape Charles, Virginia.

While slightly smaller than the event that killed the dinosaurs 66 million years ago, researchers expected it to alter Earth's global climate similarly.

Instead, they found 'our planet seemed to carry on as usual,' according to study co-author Bridget Wade with University College London (UCL).

What's more, the researchers found another giant asteroid collided with what is now Russia some 25,000 years prior and only disrupted Earth's climate for a brief period. 

That impact left a 60-mile-wide crater - known today as the Popigai crater - in northern Siberia.  

These two asteroid strikes formed the fourth and fifth largest known craters on Earth, and yet, they did not trigger any measurable climate changes over the following 150,000 years, the researchers concluded. 

'However, our study would not have picked up shorter-term changes over tens or hundreds of years, as the samples were every 11,000 years,' Wade explained.

'Over a human time scale, these asteroid impacts would be a disaster. They would create a massive shockwave and tsunami, there would be widespread fires, and large amounts of dust would be sent into the air, blocking out sunlight.' 

Roughly 35 million years ago, an enormous asteroid slammed into the ocean off the eastern coast the North American continent, but didn't cause climactic changes (STOCK)

The asteroid, between three and five miles wide, created a giant 25-mile crater in what now lies beneath Chesapeake Bay, with the center located at the southern end of Northampton County near Cape Charles, Virginia

Evidence of the asteroid impacts were found in tiny droplets of silica, which appeared like small balls of glass. 

The formations were created by the intense heat released as the asteroid impacts vaporized rocks on. 

The team inferred what Earth's climate looked like after the asteroid strikes by analyzing carbon and oxygen isotopes in more than 1,500 fossils of shelled, single-celled organisms called foraminifera.

These tiny sea creatures lived near the ocean surface or on the sea floor between 35.5 and 35.9 million years ago, and served as a record of how warm Earth's oceans were at that time. 

The fossils were found embedded within 10 feet of a rock core drilled from underneath the Gulf of Mexico by the scientific Deep Sea Drilling Project. 

The researchers found shifts in isotopes 100,000 years prior to the two asteroid impacts that suggested the ocean surface warmed 3.6 degrees Fahrenheit, and the deep ocean cooled 1.8 degrees Fahrenheit. 

But they did not find evidence of any climactic shifts around the time of the impacts or afterwards.  

Another giant asteroid that collided with what is now Russia some 25,000 years prior similarly did not disrupt Earth's climate for more than a brief period

Read More

• Scientists come up with a way to save Earth from a catastrophic asteroid collision 

'What is remarkable about our results is that there was no real change following the impacts,' Wade said in the statement.

'We expected the isotopes to shift in one direction or another, indicating warmer or cooler waters, but this did not happen.'

The researchers published their findings in the journal Communications Earth & Environment today. 

The isotope samples collected were over intervals of 11,000 years, and therefore do not reflect the short-term affects of these massive asteroid impacts, which would have been a 'disaster' over a human time scale, Wade said. 

The Chicxulub impact, for example, caused a shift in climate on a much smaller timescale of less than 25 years. But it was so extreme that it triggered the extinction of the dinosaurs.

'So we still need to know what is coming and fund missions to prevent future collisions,' Wade said.

NASA's Planetary Defense Coordination Office (PDCO) is developing strategies and protocols to prevent a catastrophic asteroid strike.

Evidence of the asteroid impacts were found in tiny droplets of silica, which appeared like small balls of glass. The formations were created by the intense heat released as the asteroid impacts vaporized rocks on

The PDCO's primary mission is finding, tracking and better understanding asteroids that could pose a threat to Earth. But it also launched the Double Asteroid Redirection Test (DART) mission in November 2021. 

This mission rammed a spacecraft into the near-Earth asteroid Dimorphos to alter its trajectory - a strategy NASA could one day use to save the planet from an oncoming asteroid. 

Even though Wade and Cheng's study did note capture the more immediate affects of the strikes, they did create a more precise timeline of climactic change, as previous studies used fossils samples over intervals longer than 11,000 years. 

What's more, using fossils that lived at different ocean depths provided a more complete picture of how the oceans responded to the asteroid strikes. 

'It was fascinating to read Earth's climate history from the chemistry preserved in microfossils,' Cheng said.

{ https://www.dailymail.co.uk/ }

05-12-2024 om 21:01 geschreven door peter  

Posted by Matt Williams

China Plans to Retrieve Mars Samples by 2031

China’s growing presence in space has been undeniable since the turn of the century. Between sending the first “taikonaut” to space in 2003 (Yang Liwei), launching the first Chinese robotic mission to the Moon (Chang’e-1) in 2007, and the deployment of their Tiangong space station between 2021-2022, China has emerged as a major power in space. Accordingly, they have bold plans for the future, like the proposed expansion of their Tiangong space station and the creation of the International Lunar Research Station (ILRS) by 2035.

In their desire to become a space power that can rival NASA, China also has its sights on Mars. In addition to crewed missions that will culminate in a “permanent base,” they intend to conduct a sample-return mission in the near future. This will be performed by the Tianwen-3 mission, which is currently scheduled to launch in 2028 and return samples to Earth by 2031. In a recent article, the Tianwen-3 science team outlined their exploration strategy, including the methods used to retrieve the samples, the target locations, and how they’ll be analyzed for biosignatures that could indicate the presence of past life.

Zengqian Hou was the article’s lead author, a geologist with the Deep Space Exploration Laboratory (DSEL) and the Chinese Academy of Geological Sciences (CAGS), and the mission team supervisor. His fellow team members included the mission’s chief designer, Liu Jizhong, and colleagues from the DSEL, the Lunar Exploration and Space Engineering Center, the Chinese Academy of Sciences (CAS), and the University of Science and Technology of China (USTC). The article was recently published in the November edition of National Science Review.

This mission is the third in China’s Tianwen (Chinese for “questions to heaven”) exploration program. The previous mission (Tianwen-1) included an orbiter, a lander, and the Zhurong rover, which reached Mars in February 2021. The successful deployment of this mission made China the third nation (after the Soviet Union and the U.S.) to land on Mars. Highlights of the mission include the mapping of the entire Martian surface by the orbiter and the discovery of hydrated minerals by Zhurong, further confirming that Mars once had liquid water on its surface.

News of this latest mission was first shared by Jizhong at the 2nd International Deep Space Exploration Conference, which took place from September 4th to 7th in Huangshan City, China. However, few details were shared at the time, though a concurrently published paper suggested that the mission could include a helicopter similar to NASA’s Ingenuity. According to the latest from Jizhong, the Tianwen-3 will consist of two launches sometime in 2028 using the Long March 5 (CZ-5) rocket. While one CZ-5 will send the orbiter/return vehicle, the second will send the lander/ascent vehicle. As Liu told the state-owned news agency Xinhua:

“China has retrieved the first-ever samples from the far side of the moon with the Chang’e-6 mission this year. Since Mars is much farther away than the moon, it will take two launches to carry out the Mars sample-return mission due to the limited carrying capacities of our current rockets. Two Long March-5 carrier rockets will be used for the mission.”

Other details include the 86 potential landing sites proposed by the team, which are primarily concentrated in the ancient Chryse Planitia and Utopia Planitia regions. These areas are considered good places to search for potential biosignatures that could be preserved remains of ancient life. This includes features that indicate the presence of past water, including delta fans, lake beds, and the coastline, suggesting the presence of a past ocean in the Northern Lowlands. The team also stated that Tianwen-3 will carry payloads developed with international partners.

They also stressed the necessity for new instruments specifically designed to detect biosignatures. To this end, they have developed a 13-phase mission plan that leverages in-situ and remote-sensing detection technologies. Liu also disclosed that the mission will rely on multi-point surface sampling, fixed-point in-depth drilling, and in-flight vehicle sampling to obtain diverse samples. They also state that China will conduct joint research with scientists worldwide on Mars samples and detection data.

What is clear from this latest news is that China intends to preempt NASA and the ESA’s proposed Mars Sample Return (MSR) mission. Due to budget cuts announced earlier this year, this mission is currently stuck in the design phase. Similarly, China has indicated that the Tianwen-4 mission will explore the Jupiter system to learn more about its moons and their evolutionary history. This mission is scheduled to launch in September 2029 and will follow on the heels of NASA’s Europa Clipper and the ESA’s JUpiter Icy Moons Explorer (JUICE).

This is in keeping with China’s pattern of following in NASA’s footsteps, catching up with them and surpassing them as the leader in space exploration. If they manage to return Martian samples to Earth before either NASA or the ESA, they will have accomplished a task no other space agency has. However, given the scientific value of these samples and the international cooperation that will go into their analysis will be to the benefit of all.

Further Reading: 

• CGTN, 
• Xinhua

{ https://www.universetoday.com/ }

05-12-2024 om 17:56 geschreven door peter  

{ https://www.universetoday.com/ }

05-12-2024 om 17:28 geschreven door peter