Fast facts: What is the Habitable Zone?

The definition of “habitable zone” is the distance from a star at which liquid water could exist on orbiting planets’ surfaces. Habitable zones are also known as Goldilocks’ zones, where conditions might be just right – neither too hot nor too cold – for life.

When searching for possibly habitable exoplanets, it helps to start with worlds similar to our own. But what does “similar” mean? Many rocky planets have been detected in Earth’s size-range: a point in favor of possible life. Based on what we’ve observed in our own solar system, large, gaseous worlds like Jupiter seem far less likely to offer habitable conditions. But most of these Earth-sized worlds have been detected orbiting red-dwarf stars; Earth-sized planets in wide orbits around Sun-like stars are much harder to detect.

And, of course, when talking about habitable exoplanets, we’re really talking about their stars, the dominant force in any planetary system. Habitable zones potentially capable of hosting life-bearing planets are wider for hotter stars. Smaller, dimmer red dwarfs, the most common type in our Milky Way galaxy, have much tighter habitable zones as in the TRAPPIST-1 system. Planets in a red dwarf's comparatively narrow habitable zone, which is very close to the star, are exposed to extreme levels of X-ray and ultraviolet (UV) radiation, which can be up to hundreds of thousands of times more intense than what Earth receives from the Sun.

This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G stars; stars less massive and cooler than our Sun are K dwarfs; and even fainter and cooler stars are the reddish M dwarfs.

NASA, ESA and Z. Levy (STScI)

Where Are We Looking for Life, and Why?

An old joke offers an answer: Asked why, on a dark night, he was looking for his missing car keys beneath a street lamp, the man answered, "because the light's better." Life on other planets might be like nothing on Earth – it could be life as we don't know it. But it makes sense, at least at first, to search for something more familiar. Life as we know it should be easier to find. And "the light's better" in the habitable zone, or the area around a star where planetary surface temperatures could allow the pooling of water.

Other similarities to Earth come into sharper focus in the search for life. Many rocky planets have been detected in Earth’s size-range: a point in favor of possible life. Based on what we’ve observed in our own solar system, large, gaseous worlds like Jupiter seem far less likely to offer habitable conditions. But most of these Earth-sized worlds have been detected orbiting red-dwarf stars; Earth-sized planets in wide orbits around Sun-like stars are much harder to detect. Yet these red-dwarfs have a potentially deadly habit, especially in their younger years: Powerful flares tend to erupt with some frequency from their surfaces. These could sterilize closely orbiting planets where life had only begun to get a toehold. That’s a strike against possible life.

Because our Sun has nurtured life on Earth for nearly 4 billion years, conventional wisdom would suggest that stars like it would be prime candidates in the search for other potentially habitable worlds. G-type yellow stars like our Sun, however, are shorter-lived and less common in our galaxy.

The artist's conception shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. More about stars ›

Stars slightly cooler and less luminous than our Sun — called orange dwarfs — are considered by some scientists as potentially better for advanced life. They can burn steadily for tens of billions of years. This opens up a vast timescape for biological evolution to pursue an infinity of experiments for yielding robust life forms. And, for every star like our Sun there are three times as many orange dwarfs in the Milky Way.

K dwarfs, are the true "Goldilocks stars," said Edward Guinan of Villanova University, Villanova, Pennsylvania. "K-dwarf stars are in the 'sweet spot,' with properties intermediate between the rarer, more luminous, but shorter-lived solar-type stars (G stars) and the more numerous red dwarf stars (M stars). The K stars, especially the warmer ones, have the best of all worlds. If you are looking for planets with habitability, the abundance of K stars pump up your chances of finding life."

Exoplanet temperature, size, star type: the galaxy offers up a menu of worlds that echo aspects of our own, yet at the same time are vastly different.

Traditional picture of the habitable zone – not too hot, not too cold.

NASA

{ https://www.nasa.gov/ }

17-02-2025 om 23:00 geschreven door peter  

Even if we restrict ourselves to the basic biochemistry that makes Earthly life possible, we have many more options than we naively thought. Hycean worlds, planets thought to be englobed by water surrounded by thick hydrogen atmospheres, once thought to be too toxic for any kind of life, might be even more suitable than terrestrial worlds.

What about tidally-locked planets around red dwarf stars, like our nearest neighbor Proxima b and the intriguing system of TRAPPIST-1? Conditions on those planets might be hellish, with one side facing the incessant glare of its star and the other locked in permanent night. Neither of those extremes seem suitable for life as we know it. But even those worlds can support temperate atmospheres if the conditions are just right. A delicate balancing act for sure, but a balancing act that every life-bearing planet must walk.

Our galaxy contains billions of dead stars, the white dwarves and neutron stars. We know of planets in those systems. Indeed, the first exoplanets were discovered around a pulsar. Sometimes those dead stars retain planets from their former lives; other times the planets assemble anew from the stellar wreckage. In either case, the stars, though dead, are still warm, providing a source of energy for any life that might find a home there. And considering the sheer longevity of those stars the incredibly long history of our galaxy, life has had many chances to appear – and sustain itself – in systems that are now dead.

Who needs planets, anyway? Methanogens could take advantage of the exotic, cold chemistry of molecular clouds, feasting on chemicals processed by millennia of distant high-energy starlight. It might even be possible for life to sustain itself in a free-floating biological system, with the gravity of its own mass holding on to an atmosphere. It’s a wild concept, but all the foundational functions of a free-floating habitat – scaffolding, energy capture and storge, semi-permeable membranes – are found on terrestrial life.

We should absolutely continue our current searches – after all, they’re not groundless. But before we invest in the next generation of super-telescopes, we should pause and reconsider our options. We should invest in research that pushes the edges of what life means and where it can exist, and we should explore pathways to identifying and observing those potential habitats. Only after we have extended research along these lines can we decide on a best-case strategy.

In other words, we should replace a goal, that of finding life like our own, with a vision of finding life wherever we can. Nature has surprised us many times in the past, and we shouldn’t let our biases and assumptions get in the way of our path of discovery.

The definition of “habitable zone” is the distance from a star at which liquid water could exist on orbiting planets’ surfaces. Habitable zones are also known as Goldilocks’ zones, where conditions might be just right – neither too hot nor too cold – for life.

{ https://www.universetoday.com/ }

17-02-2025 om 22:43 geschreven door peter  

{ https://www.universetoday.com/ }

17-02-2025 om 22:13 geschreven door peter  

They began their study by working backward from the known properties of ‘Oumuamua.

When it was visible to Earth’s telescopes for just a few months in 2017, it showed an intensely variable brightness, changing from bright to dim every four hours. Astronomers interpreted this variability as an elongated, cigar-shaped object tumbling through space.

Two other things made ‘Oumuamua unique. First, it appeared to have a dry, rocky surface, akin to the asteroids known in our solar system. But it also changed its orbit in a way that could not purely be explained by the laws of gravity – something else made it change direction.

Redirections like this are sometimes seen in icy comets. As they approach the Sun, off-gassing released from the heated ice acts like a thruster, changing the comet’s trajectory.

Somehow, ‘Oumuamua displayed a mix of both comet-like and asteroid-like properties.

One plausible explanation, proposed in 2020, is that ‘Oumuamua-like objects are formed by tidal fragmentation. That’s when a ‘volatile-rich’ parent body (like a large comet) passes too close to its star at high speeds, shattering it into long, thin shards. The heating process in these extreme interactions causes the formation of an elongated rocky shell, but preserves an interior of subsurface ice. This unique combination, not seen in our own solar system, would explain ‘Oumuamua’s orbital maneuvers despite its rocky composition.

It also explains why we don’t tend to see them in our solar system, because “ejected planetesimals experienced tidal fragmentation at more than twice the rate of surviving planetesimals (3.1% versus 1.4%),” the authors write. In other words, if the orbital forces are strong enough for tidal fragmentation to happen, it also means they’re strong enough to kick the object out of the system entirely.

Interstellar space may therefore be full of dagger-shaped shards of rock and ice (an exaggeration, but a fun quote for dinner parties nonetheless).

The simplest star system that could cause this type of tidal fragmentation are those home to white dwarfs. These are the extremely dense, dead cores of old exploded stars. A white dwarf, encircled by a belt of distant comet-like objects, similar to the Sun’s Oort cloud, could spawn ‘Oumuamua clones with regular frequency.

But the process is enhanced in systems that host Jupiter-sized planets.

The exception is ‘Hot Jupiters’ that orbit close to their star. These are less likely to interact with objects subject to tidal fragmentation.

But Jupiter-sized planets distant from their host star are very effective at producing ‘Oumuamua clones, especially if they have eccentric orbits. But even here, it’s not a perfect match for the origin of ‘Oumuamua, because these interactions tend to produce shards that are not as elongated, and at a rate lower than what is expected for ‘Oumuamua-type objects.

The authors conclude that the planetary systems most likely to have spawned ‘Oumuamua are those with many planets, which are more “efficient at producing interstellar objects,” the authors say, though they propose a few other possibilities too.

So while there is now a strong, plausible explanation for the process that birthed ‘Oumuamua, the type of solar system that produced it is still very much an open question.

• Xi-Ling Zheng amd Ji-Lin Zhou, “Configuration of single giant planet systems generating ‘oumuamua-like interstellar asteroids.” Monthly Notices of the Royal Astronomical Society.

{ https://www.universetoday.com/ }

17-02-2025 om 21:45 geschreven door peter  

Scientists are baffled after discovering a mysterious radioactive 'blip' deep under the Pacific Ocean

• READ MORE: Scientists find structures under the ocean that 'shouldn't exist' 

By WILIAM HUNTER_

Scientists have been left baffled after discovering something vast and radioactive lurking in the depths of the Pacific Ocean.

While it might sound like the start of the next Godzilla movie, researchers say this 'blip' is a very real phenomenon.

An international team of scientists has found unexpectedly high levels of the rare radioactive isotope beryllium-10 in samples from the Pacific seabed.

And they believe it could have been caused by a blast of radiation from space more than 10 million years ago.

Beryllium-10 is an isotope - a variant of an element with a different number of neutrons in its atomic nuclei, formed when cosmic rays hit oxygen and nitrogen in the upper atmosphere.

After forming, this isotope falls to the ground in the rain and settles to the bottom of the seabed at a fairly constant rate.

However, when the researchers looked at samples of the seabed from 10 million years ago, they found that the levels of beryllium-10 were almost twice what they had expected.

Study author Dr Dominik Koll, from Helmholtz-Zentrum Dresden-Rossendorf, Germany, says: 'We had stumbled upon a previously undiscovered anomaly.'

Scientists have been baffled to find something vast and radioactive lurking beneath the Pacific Ocean. Although it sounds like the plot of the next Godzilla movie, the researchers say this anomaly is very real 

Researchers discovered an unexpectedly high amount of the rare radioactive isotope beryllium-10 from samples taken from the bottom of the Pacific Ocean. This compound is formed when cosmic rays hit oxygen and nitrogen in the atmosphere and falls to the ground in rain before sinking to the seabed 

In their study, published in Nature Communications, the researchers looked at the accumulation of Beryllium-10 in the seabed deep below the Pacific Ocean.

These unique samples were collected from several miles beneath the water and are made up of a mixture of iron and manganese called a ferromanganese crust.

Using a highly sensitive method called Accelerator Mass Spectrometry, the researchers were surprised to find an unexpected spike in beryllium-10 levels occurring about 10 million years ago.

To ensure this wasn't a fluke, Dr Koll and his colleagues looked at samples taken from elsewhere in the Pacific, but these samples all showed the same anomalous blip.

The researchers argue that there are two possible ways to explain this strange phenomenon: one earthly, and one extraterrestrial.

In one scenario, the unusual radioactive buildup could have been caused by the ocean circulation around the Antarctic suddenly and drastically changing 10 to 12 million years ago.

Dr Koll says: 'This could have caused beryllium-10 to be unevenly distributed across the Earth for a period of time due to the altered ocean currents.'

'As a result, beryllium-10 could have become particularly concentrated in the Pacific Ocean.' 

The levels of beryllium-10 should have been fairly consistant though time, but researchers found a significant spike in its abundance about 10 million years ago (illstrated) 

These samples (pictured left) came from a region of the northeast Pacific (shaded yellow) that currently sits by major ocean currents (red and blue lines). The researchers suggest that massive changes to  thes currents 10 million years ago could have built up more beryllium-10

What is beryllium-10?

Beryllium-10 is an isotope of beryllium which contains 10 neutrons in its nucleus.

This makes the atom unstable and radioactive, so it slowly decays into boron over millions of years.

Beryllium-10 has a half-life - the time needed for half of its atoms to decay - of 1.4 million years.

This means it can be used to date objects from more than 10 million years ago.  

In the more out-of-this-world theory, something might have happened in space which exposed the Earth to a sudden burst of radiation.

This could have been triggered by the after-effects of a near-Earth supernova, which would have bathed the planet in intense radiation.

Alternatively, the planet might have briefly lost its protective solar shield, known as the heliosphere, after passing through a dense interstellar cloud.

In either case, this would mean that beryllium-10 should be unusually common 10 million ago in oceans all around the world.

Dr Koll says: 'Only new measurements can indicate whether the beryllium anomaly was caused by changes in ocean currents or has astrophysical reason.

'That is why we plan to analyze more samples in the future and hope that other research groups will do the same.'

Discovering that this anomaly is present all around the world could be extremely valuable for scientists looking into the distant past.

Even though radioactive isotope dating is generally accurate, researchers still need common reference points in order to compare different sets of samples. 

Alternatively, the beryllium-10 could have been formed by the radioactive blast of supernova such as the one which left behind the Crab Nebula (pictured). This intense radiation would have led to more beryllium-10 forming all over the world 

For example, researchers studying more recent populations can often look for the spikes in C14 isotopes associated with nuclear weapons testing to help date organisms.

Dr Koll says: 'For periods spanning millions of years, such cosmogenic time markers do not yet exist.

'However, this beryllium anomaly has the potential to serve as such a marker.'

So, if this spike could be found all around the world, it would let researchers compare completely different archives by synching up to the same unexpected spike 10 million years ago.

{ https://www.dailymail.co.uk/ }

15-02-2025 om 22:32 geschreven door peter  

NASA And Japan Moon Landing Update

RELATED VIDEOS

{ https://www.bing.com/?FORM=Z9FD1 }

15-02-2025 om 22:02 geschreven door peter  

The concept they used is called inertial morphing. In the case of SPLITTER, the robots “adjust inertia with changes in limb configurations and tether length,” according to lead author Yusuke Tanaka in an interview with TechXplore. The researchers turned to a technique called Model Predictive Control (MPC) to determine how each variable needs to be adjusted.

MPC is used in various industries and comes as advertised, with a model (i.e., a mathematical representation of the robots) and a prediction, which reflects what the software estimates will happen to the model next. With the model’s current state and expected next state, a controller can change the variables that affect the model’s state. Those changes will result in a stable flying path, allowing SPLITTER to soar through the skies, even without air. It also uses a physical phenomenon known as the Tennis Racket Theorem, which describes how an object can flip rotation around its intermediate axis while rotating around it. Most famously, this was demonstrated on the ISS with a t-handle. It looks chaotic, but the mathematics behind the motion are well-understood.

Implementing it in a tethered robotic system is another matter altogether, though. While SPLITTER is flying, it looks a lot like a bola used in ladder ball, except instead of round spheres on each end, it’s a robot body with four legs splayed out in different directions. The orientation of how those legs are spread out and the length of the tether connecting the two ends are the variables the MPC controls to stabilize its flight. SPLITTER can operate without heavy attitude control hardware, like reaction wheels or thrusters.

It also allows the system to perform other actions, like spelunking, where one robot is anchored firmly to the top of a cave system while the other rappels using the tether. Both robots only weigh about 10kg each on Earth, as well, which would make them even more agile on a world with smaller gravity like the Moon or an asteroid.

This isn’t the first robot system the RoMeLa lab designed for this purpose. They initially worked on a robot called the Spine-enhanced Climbing Autonomous Legged Exploration Robot) (SCALER), which had its limitations as they found the limbed climbing robot was too slow.

With SPLITTER, the research team thinks they have a better concept that can both traverse terrain faster and collect data that a robot tied to the ground would be unable to do. Unfortunately, for now, at least, SPLITTER is best described as a computer model, though some preliminary work has been done on the physics of MPC controlling a reaction wheel. Researchers at the lab intend to continue working on the concept, so maybe soon we’ll see a bola robot test jumping near Los Angeles.

Learn More:

• TechXplore – Modular robot design uses tethered jumping for planetary exploration
• Tanaka, Zhu, & Hong – Tethered Variable Inertial Attitude Control Mechanisms through a Modular Jumping Limbed Robot
• UT – Miniaturized Jumping Robots Could Study An Asteroid’s Gravity
• UT – A Jumping Robot Could Leap Over Enceladus’ Geysers

Lead Image:

• Depiction of one SPLITTER robot descending into a crater while the other anchors on the rim.
  Credit – Yusuke Tanaka, Alvin Zhu, & Dennis Hong

{ https://www.universetoday.com/  }

15-02-2025 om 16:00 geschreven door peter  

Large asteroids in the Main Asteroid Belt (MAB) are easier to study. Their large sizes mean they produce a bigger signal when observed, and astronomers can more easily determine their orbits. However, the MAB holds many smaller asteroids around 100-200 meters. There could be hundreds of millions of them. They’re big enough to devastate entire cities if they strike Earth, and they’re more difficult to track. The first step in determining their orbits is determining their distances, which is challenging and takes time.

Recent research submitted to The Astronomical Journal presents a new method of determining asteroid distances in much less time. It’s titled “Measuring the Distances to Asteroids from One Observatory in One Night with Upcoming All-Sky Telescopes” and is available at arxiv.org. The lead author is Maryann Fernandes from the Department of Electrical and Computer Engineering at Duke University.

The Vera Rubin Observatory (VRO) should see its first light in July 2025. One of its scientific objectives is to find more small objects in the Solar System, including asteroids, by scanning the entire visible southern sky every few nights. If it moves and reflects light, the VRO has a good chance of spotting it. However, it won’t automatically determine the distance to asteroids.

“When asteroids are measured with short observation time windows, the dominant uncertainty in orbit construction is due to distance uncertainty to the NEO,” the authors of the new paper write. They claim their method can shorten the time it takes to determine an asteroid’s distance to one night of observations. It’s based on a technique called topocentric parallax.

Topocentric parallax is based on the rotation of the Earth. In a 2022 paper by some of the same researchers, the authors wrote that “Topocentric parallax comes from the diversity of the observatory positions with respect to the center of the Earth in an inertial reference frame. Observations from multiple observatories or a single observatory can measure parallax because the Earth rotates.”

In the two years since that paper, the researchers have refined their method. The research expands on previous algorithms and tests the technique using both synthetic data and real-world observations.

“In this paper, we further develop and evaluate this technique to recover distances in as quickly as a single night,” the authors write in the new paper. “We first test the technique on synthetic data of 19 different asteroids ranging from ~ 0.05 AU to ~ 2.4 AU.”

The figure below shows the results of the test with synthetic data. Each asteroid was observed six times in one night, and two different equations were employed to process the data.

The researchers also tested their method by taking 15 observations of each asteroid over five nights (3 per night). In this test, Equation 1 performed poorly, while Equation 2 performed well.

Of course, the distance to the asteroid affected the accuracy of the measurements. The closer the object was, the more precise the measurement was. The paper notes that the method was able to recover distances “with uncertainties as low as the ~ 1.3% level for more nearby objects (about 0.3 AU or less) assuming typical astrometric uncertainties.”

After these tests with synthetic data, the team acquired their own single-night observations of two asteroids using a different algorithm. The real observations produced a less precise result, but it was still a meaningful improvement. The authors explain that they were able to recover distances “to the 3% level.”

So, what do all these tests, equations, and algorithms boil down to?

When we hear of an asteroid that could potentially strike Earth in a few years, people can wonder why the situation is so uncertain. Shouldn’t we know if an asteroid is heading straight for us? Trying to determine the orbit of these small rocks from tens of millions of km away is extremely difficult. An AU is almost 150 million km (93 million miles). 2024 YR, the latest asteroid of concern, is only 40 to 90 metres (130 to 300 ft) in diameter. Those numbers illustrate the problem.

If this method can improve the accuracy of our distance measurements and do it based on a single night of observations, that’s a big improvement.

The technique can be applied to data generated by the Vera Rubin Observatory and the Argus Array. According to the authors, “distances to NEOs on the scale of ~ 0.5 AU can be constrained to below the percent level within a single night.” As the study shows, the accuracy of those measurements from a single-site observatory depends heavily on the spacing between individual observations. If multiple observatories at different sites are used on the same night, the accuracy increases.

Though larger asteroids, like the one that wiped out the dinosaurs, tend to remain stable in the main asteroid belt, smaller asteroids are more easily perturbed and can become part of the NEO population. An impact from a smaller asteroid might not spell the end of civilization, but it can still be extremely destructive.

Anything humanity can do to understand the asteroid threat is wise. Many asteroids have struck Earth in the past, and it’s only a matter of time before another one comes our way. If we can see it coming in advance, we can try to do something about it.

Research: 

• Measuring the Distances to Asteroids from One Observatory in One Night with Upcoming All-Sky
  Telescopes

{ https://www.universetoday.com/  }

15-02-2025 om 15:39 geschreven door peter  

Scientists Uncover Possible Explanation for Bizarre ‘Atmospheric Ghosts’ Phenomenon

To be clear, we’re talking about the afterglow from transient luminous events, not the specters of dead people.

by Doris Elín Urrutia

 

Thomas Ashcraft

Four years ago, a green “ghost” appeared over a thunderstorm cloud in the Mediterranean Sea. To the delight of Spanish scientists, this ephemeral sighting finally offered a rare window into a little-known phenomenon playing out high in Earth’s skies.

When lightning strikes, it sometimes triggers the release of a violent optical emission at altitudes between 50 and 90 km above the thunderstorm cloud. These millisecond-long events, called transient luminous events (TLEs), are mysterious.

They can be shaped like jellyfish. These are known as sprites. Other TLE forms exist, boasting playful names like halos and elves. Just a few years ago, thrill seekers and citizen scientists discovered a new TLE, hovering above a sprite, called a ghost. While sprites appear red owing to the nitrogen in Earth’s atmosphere, and blue at more shallow altitudes due to higher atmospheric pressure, ghosts are green. They appear during and after the sprites, like fuzz on top of the jellyfish.

This puzzling afterglow was the subject of a new paper published in the journal Nature Communications on Tuesday.

Finding a Good Ghost

Researcher María Passas Varo led a team to use a special instrument called the Granada Sprite Spectrograph and Polarimeter (GRASSP), located outside Barcelona, to make a clear ghost sighting.

She and other atmospheric researchers were intrigued when, in the early half of 2019, storm chaser Hank Schyma noticed something new: in the wake of a sprite over the skies of Oklahoma, there was a greenish afterglow. He called the emerald-colored splotch a ghost, short for Green emissions from excited Oxygen in Sprite Tops. The idea behind the name was that, since oxygen is associated with the verdant tones of auroras, that the gas creates the ghosts.

Passas Varo, a telecommunications engineer, spectroscopist, and surveyor of atmospheric electricity based at the Astrophysics Institute of Andalucía in Spain, searched relentlessly for a new ghost. But finding one that GRASSP could glean a lot of data from was hard.

“We have analyzed more than 2,000 spectra, one by one, with the naked eye. We only found one good spectrum of a ghost. So, it is a lot of work. It is tedious,” she tells Inverse.

Then they finally found a science-worthy ghost, radiating from a thunderstorm cloud in the Mediterranean Sea on September 21, 2019. It was their best candidate for spectrographic analysis, in which the team peered into light from the ghost for clues about its composition.

They found a surprise. Oxygen was present, as they expected. But the team also found evidence of iron.

Iron is present in Earth’s upper atmosphere. It comes from the interplanetary dust particles that enter our atmosphere. But according to Passas Varo, it’s usually found at much higher altitudes.

Approximately one in every 100 sprites have ghosts. These events sometimes happen, but aren’t consistent. What makes a ghost appear could be a combination of different phenomena, and iron might provide a special clue.

A Need for Harmony

Cumulonimbus clouds are towers made of water droplets and ice crystals. These tiny particles journey along the updraft from the hot base of the cloud higher and higher until they reach the chilly top. Sometimes, they become larger molecules. If they bang against one another, they produce static electricity. These charged particles create lightning.

What goes down must be balanced in another form, and this need for harmony could be what causes the sprites and jets and all the other TLE oddities.

“When the lightning occurs, when the lightning strikes the ground, then an electric field appears above the cloud because you have to maintain, somehow, the balance of the electric field of the global electrical circuit,” Passas Varo tells Inverse. “Once you have this big discharge in the form of huge lightning downwards, then an electric field develops upwards. And this electric field develops a transient luminous event.”

One possible explanation for ghosts is that the sonic boom we know as thunder is, in one way or another, disrupting the iron from its usual altitude. Gravity waves on Earth, which are vertical, could also be playing a role in producing ghosts.

But what is clear is that a plethora of new observations are necessary. Passas Varo and the team have one good spectrum of a ghost but say it will take 99 more to get a clearer picture of what’s really happening.

{ https://www.inverse.com/ }

15-02-2025 om 00:00 geschreven door peter  

Scientists pinpoint exactly WHERE the 'city-destroying' asteroid could strike Earth in 2032

• READ MORE: Video shows 'city-killer' asteroid hitting Earth in 2032

By WILIAM HUNTER

The terrifying prediction that a 'city-destroying' asteroid is hurtling towards Earth has set alarm bells ringing at the world's space agencies.

Now, a NASA scientist has predicted exactly where the asteroid 2024 YR4 could strike.

David Rankin, an engineer with the NASA-funded Catalina Sky Survey Project, has sketched the 'risk corridor' according to the asteroid's current trajectory.

If 2024 YR4 really does hit Earth in 2032, it should fall somewhere in a narrow band stretching from northern South America across the Pacific to sub-Saharan Africa and into Asia.

Worryingly, this path extends over several densely populated regions including Chennai, India and Hainan Island, China.

Currently, NASA estimates that the asteroid has a one in 48, or 2.1 per cent, chance of colliding with the planet on December 22, 2032.

And with a diameter of up to 90 metres (300ft), or roughly the size of the Statue of Liberty, it could cause devastating damage to any populated area along the risk corridor.

If it were to strike, experts suggest it could unleash a blast equal to eight megatons of TNT - more than 500 times the size of the atomic bomb dropped on Hiroshima.

Scientists have predicted the exact path (shown in red) where the city-destroying asteroid 2024 YR4 could hit Earth. It should fall somewhere in a narrow band stretching from northern South America across the Pacific to sub-Saharan Africa and into Asia 

2024 YR4 was first detected in December last year but has quickly shot to the top of NASA's and the European Space Agency's (ESA) impact risk tables.

The asteroid is currently the only large asteroid with an impact probability greater than one per cent and has been awarded the rare rating of three on the Torino Scale, a scale for measuring the danger posed by asteroids.

The 'God of Chaos' asteroid 99942 Apophis is the only other object in the history of astronomy to be given a rating of three or higher on this scale.

While the odds of 2024 YR4 hitting Earth are still slim, Dr Rankin was able to use data about its orbit to predict where it might hit.

In the scenario where the asteroid does indeed collide with Earth, the 'risk corridor' threatens countries including India, Pakistan, Bangladesh, Ethiopia, Sudan, Nigeria, Venezuela, Colombia, and Ecuador.

Where it lands will also determine just how powerful the impact is, with regions at the end of the corridor more likely to receive a glancing blow. 

However, there currently isn't enough information to say where along this risk corridor the asteroid is most likely to hit.

Dr Rankin told Space.com: 'Size and are big players in possible damage, along with impact location.

NASA predicts that the asteroid 2024 YR4 currently has a one in 48, or 2.1 per cent, chance of hitting Earth on December 22, 2032 (stock image)

'It's hard to constrain size and composition with the current orbital situation, as it's outbound. Typically, the best way to constrain size is with radar observations and those are not possible right now.'

It is currently estimated that the blast would be similar in size to the Tunguska asteroid which detonated in an air-burst explosion in 1908.

While this blast hit an unpopulated area, the shockwave still flattened an estimated 80 million trees over 830 square miles (2,150 square kilometres) - more than twice the land area of New York.

At the higher end of estimates, scientists suggest this explosion could have been equivalent to 15 megatons of TNT.

A blast this powerful would topple residential buildings and cause fatalities up to 12 miles (18.9 km) in any direction from the epicentre.

In the coming months, NASA and ESA hope to use Earth's most powerful telescopes to further refine their predictions about the asteroid's orbit.

This includes a rare emergency decision to grant an international team of scientists the use of the James Webb Space Telescope (JWST) to study 2024 YR4.

This team will use the JWST's infrared sensors to measure the heat radiating from the asteroid to make a better prediction of its size and orbit.

With an estimated size of up to 90 metres (300 ft), or roughly the size of the Statue of Liberty, 2024 YR4 could hit Earth with a blast equal to eight megatons of TNT (artist's impression)

Asteroid 2024 YR4 is about the same size as the Tunguska asteroid, which caused the largest impact event in recorded history when it shot through Earth's atmosphere in 1908, flattening 830 square miles (2,150 square km) of forest (pictured)

Scientists will also have a good opportunity to learn more about the asteroid when it makes its first close pass of Earth in March at a distance of around 5 million miles (8 million kilometres).

The world's space agencies currently predict that the impact probability will drop towards zero as they learn more, but an impact cannot currently be ruled out.

A new simulation of the asteroid's path also presents a slim possibility that it could hit the moon instead of Earth.

Dr Rankin's calculations suggest that there is a one in 333 chance that 2024 YR4 will collide with the lunar surface, creating a brilliant but otherwise harmless explosion that could be seen from Earth with the naked eye. 

However, for the countries along this predicted risk corridor, these predictions raise the chilling possibility that they may face a devastating collision within the next eight years.

{ https://www.dailymail.co.uk/ }

14-02-2025 om 22:00 geschreven door peter  

It’s a familiar sight to see astronauts on board ISS on exercise equipment to minimise muscle and bone loss from weightlessness. A new study suggests that jumping workouts could help astronauts prevent cartilage damage during long missions to the Moon and Mars. They found that the knee cartilage in mice seems to grow stronger after jumping exercises, potentially counteracting the effects of low gravity on joint health. If effective in humans, this approach could be included in pre-flight routines or adapted for space missions.

In space, astronauts experience significant loss of bone and muscle mass due to microgravity. Without Earth’s gravitational pull, bones lose density, increasing fracture risk, while muscles, especially in the lower body and spine, weaken from reduced use. This deterioration can impair mobility when back on Earth and effect overall health. To combat this, astronauts follow rigorous exercise routines, including resistance and cardiovascular training, to maintain strength and bone integrity. 

The next obvious step as we reach out into the Solar System is the red planet Mars. Heading that far out into space will demand long periods of time in space since its a 9 month journey there. Permanent bases on the Moon too will test our physiology to its limits so managing the slow degradation is a big challenge to space agencies. A paper published by lead author Marco Chiaberge from the John Hopkins University has explored the knee joints of mice and how their cartilage grows thicker if they jump! They suggest astronauts should embed jumping activities into their exercise regiment. 

Cartilage cushions the joints between bones and decreases friction allowing for pain free movement. Unlike many other tissues in the body, cartilage does not regenerate as quickly so it is important to protect it. Prolonged periods of inactivity, even from bed rest but especially long duration space flight can accelerate the degradation. It’s also been shown that radiation from space can accelerate the effect too. 

To maintain a strong healthy body, astronauts spend a lot of time, up to 2 hours a day running on treadmills. This has previously shown to slow the breakdown of cartilage but the new study has shown that jumping based movements is particularly effective. 

(Credit: Merlin74/Shutterstock)

The team of researchers found that, over a nine week program of reduced movement, mice experienced a 14% reduction in cartilage thickness in joints. Other mice performed jumping movements three times a week and their cartilage was found to be show a 26% increase compared to a control group of mice. Compared to the group that had restricted movement, the jumping mice had 110% thicker cartilage. The study also showed that jumping activities increased bone strength too with the jumping mice having a 15% higher density than the control.

An interesting piece of research but further work is needed to see whether jumping would herald in the same benefits to humans but the study is promising. If so, then jumping exercises are likely to be a part of pre-flight and inflight exercise programs for astronauts. It is likely that for this to be a reality in the micro-gravitational environment, astronauts will be attached to strong elasticated material to simulate the pull of gravity. 

Source : 

• Jumping Workouts Could Help Astronauts on the Moon and Mars, Study in Mice Suggests.

{ https://www.universetoday.com/ }

14-02-2025 om 18:22 geschreven door peter  

via GIPHY

Earth has noctilucent clouds, too. They form in the upper atmosphere and are only visible during twilight when the atmosphere’s lower layers are in the shade and the upper atmosphere is sunlit. They form from water ice crystals between 76 to 85 km altitude and are the highest clouds in the atmosphere.

Mars’ noctilucent clouds are similar, but the main difference is that they contain carbon dioxide ice. They form at an altitude of around 60 to 80 km and are also classified as mesospheric clouds. On Mars, they occur in the Fall over the southern hemisphere. Only Mars’ high-altitude clouds containing carbon dioxide ice display iridescent colours.

This is the fourth year in succession that Curiosity has seen these noctilucent clouds. Its Mastcam instrument has different filters that let it see different wavelengths of light, and some of those filters are used to study the composition and particle size in clouds. It also has stereo vision, which helps scientists determine cloud height, shape, and the speed at which they’re moving. It can also observe the Sun through filters and determine how much sunlight the atmosphere is blocking. That tells scientists how much dust and ice is in the atmosphere and how it changes over time.

A November 2024 paper titled “Iridescence Reveals the Formation and Growth of Ice Aerosols in Martian Noctilucent Clouds” summarized Curiosity’s images and findings. The lead author is Mark Lemmon, an atmospheric scientist with the Space Science Institute in Boulder, Colorado.

“I’ll always remember the first time I saw those iridescent clouds and was sure at first it was some color artifact,” he said in a press release. “Now it’s become so predictable that we can plan our shots in advance; the clouds show up at exactly the same time of year.”

These clouds form only in early Martian fall and only in the southern hemisphere. Their iridescence is from uniform particle size, which indicates that the clouds had a brief evolution in a uniform environment. When clouds are both noctilucent and iridescent, they’re called nacreous clouds. It’s interesting to note that these colours would be easily seen by an astronaut on the Martian surface.

One of the mysteries behind these clouds concerns their location. They’re only seen in Mars’ southern hemisphere, and the Perseverance rover, which is in the Jezero Crater in the northern hemisphere, has never seen them. It seems pretty clear that they only form in certain locations, but the reasons why are unknown.

Lemmon says that gravity waves, which are atmospheric phenomena separate from astrophysical gravitational waves, could be responsible. They cool the atmosphere and could give rise to clouds of frozen CO2. “Carbon dioxide was not expected to be condensing into ice here, so something is cooling it to the point that it could happen. But Martian gravity waves are not fully understood, and we’re not entirely sure what is causing twilight clouds to form in one place but not another,” Lemmon said.

Scientists need more data to better understand these clouds. Curiosity wasn’t the only one to see them; the InSight lander did, too. But they could only see for a few hundred kilometres around their landing sites and their data is incomplete. “Orbiters capable of sunset and twilight times could constrain the cloud altitude,” Lemmon and his co-authors write in their paper.

There are unanswered questions about these clouds. Scientists would like to understand how quickly particles in these clouds evolve. They’d also like to know what the nature of the corona-forming layer is. A larger data sample could help answer these questions, as could more time-lapse imagery.

• Press Release: A Rainbow-colored “Feather” in the Martian Sky
• Press Release: NASA’s Curiosity Rover Captures Colorful Clouds Drifting Over Mars
• Published Research: Iridescence Reveals the Formation and Growth of Ice Aerosols in Martian Noctilucent Clouds

{ https://www.universetoday.com/ }

14-02-2025 om 18:01 geschreven door peter  

Alien life breakthrough as astronomers detect 'coherent' radio signal from distant planet

Astronomers have detected a 'coherent' radio signal from a distant planet, reigniting hope for the existence of extraterrestrial life.

The signal is thought to originate from a far-off, Earth-sized planet, suggesting it might possess a magnetic field similar to our own.

Scientists regularly monitor exoplanets and their potential to carry life. 85 new exoplanets were discovered outside our solar system, which could unlock secrets of the universe.

American astronomers have christened this rocky exoplanet 'YZ Ceti b,' asserting that it's a prime candidate for an Earth-like magnetic field, which could be crucial in humanity's quest for alien life.

The discovery has been hailed as significant for identifying a planet likely to have a magnetic field and offering a future technique to discover more such planets.

Using a radio telescope, the scientists detected a recurring radio signal from exoplanet YZ Ceti b, located approximately 70.5 trillion miles from Earth.

They speculate that these waves could be produced by interactions between the exoplanet's magnetic field and its host star, a small red dwarf named YZ Ceti.

This finding is essential for pinpointing a planet likely to have a magnetic field and establishing a foundation to discover similar planets in the future.

The researchers further suggested that this could mean witnessing the Northern Lights phenomenon - a result of interactions between magnetic fields and solar weather - on distant planets and stars could be possible.

Magnetic fields are vital in preventing a planet's atmospheric erosion caused by stellar emissions over time.

Drs. Sebastian Pineda and Jackie Villadsen have recently identified a repetitive radio signal from YC Ceti, a red dwarf star located 12 light years away. For context, one light year is nearly 5.88 trillion miles.

The Karl G. Jansky Very Large Array, a prominent radio telescope managed by the National Radio Astronomy Observatory under the US National Science Foundation, was the instrument that allowed them to gain deeper insights into the magnetic dynamics between distant stars and their planets.

This groundbreaking work, outlined in Nature Astronomy, was also funded by the independent federal agency, the National Science Foundation (NSF).

Joe Pesce from NSF, who works as the program director for the National Radio Astronomy Observatory, hails these discoveries as key in the ongoing quest to find life on other worlds, emphasizing, "The search for potentially habitable or life-bearing worlds in other solar systems depends in part on being able to determine if rocky, Earth-like exoplanets actually have magnetic fields."

Recent research marks a significant advancement in exoplanet studies, indicating that some rocky planets beyond our solar system may have magnetic fields. This discovery was achieved through a novel technique that could help identify more of these intriguing worlds.

Dr. Pineda of the University of Colorado, located on America's west coast, expressed the team's elation at detecting planetary radio emissions similar to those Earth emits: "We saw the initial burst, and it looked beautiful," he said enthusiastically.

Moments of scientific triumph followed as Pineda recounted: "When we saw it again, it was very indicative that, OK - maybe we really have something here."

Dr. Pineda noted that a sturdy magnetic field can be pivotal for a planet's ability to retain its atmosphere.

From the other side of the country, Assistant Professor Villadsen of Bucknell University remarked on the distinctiveness of their findings: "I witnessed something that no one has observed before."

Prior detections of exoplanetary magnetic fields were mainly limited to gas giants resembling Jupiter. However, unearthing Earth-sized counterparts calls for different, refined methods.

Since magnetic fields are inherently intangible, detecting their presence around distant planets poses a significant astronomical challenge that Assistant Prof Villadsen and her team are committed to addressing.

She explained their strategy: "We're looking for planets that are really close to their stars and are a similar size to Earth."

"These planets are way too close to their stars to be somewhere you could live, but because they are so close the planet is kind of ploughing through a bunch of stuff coming off the star."

"If the planet has a magnetic field and it ploughs through enough star stuff, it will cause the star to emit bright radio waves."

{ https://www.the-express.com/ }

14-02-2025 om 17:05 geschreven door peter  

Strange Rock Found on Mars with Zebra Markings Has NASA Scientists ...

NASA Discovers New Substances on Mars: Implications for Future Exploration and Understanding of the Red Planet

Introduction

The quest to understand Mars has captivated scientists and enthusiasts alike for decades. With its striking similarities to Earth and its potential to harbor life, the Red Planet has been a focal point of exploration for NASA and other space agencies around the globe. Recent discoveries of new substances on Mars have opened up exciting avenues for research and exploration. This article delves into the significance of these findings, the methods used to uncover them, and what they mean for the future of Mars exploration.

The Historical Context of Mars Exploration

Mars, often referred to as the "Red Planet" due to its reddish appearance from iron oxide (rust) on its surface, has been a subject of human fascination for centuries. The first observations of Mars were made through telescopes in the 1600s, but it wasn't until the 20th century that space missions began to provide detailed information about its atmosphere, surface, and potential for life.

NASA's Viking missions in the 1970s were pivotal, providing the first close-up images and data about the Martian surface. Subsequent missions, including the Mars Pathfinder, Mars Exploration Rovers (Spirit and Opportunity), and the Mars Science Laboratory (Curiosity), have progressively advanced our understanding of the planet.

The Curiosity rover, which landed in Gale Crater in 2012, has been a key player in Mars exploration. It has analyzed various rocks and soil samples, providing evidence of past water flows and organic molecules, which are crucial for understanding the planet's potential for life.

NASA Finds Ancient Organic Material, Mysterious Methane on Mars - This low-angle self-portrait of NASA’s Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called “Buckskin” on lower Mount Sharp. 

Credits: NASA/JPL-Caltech/MSSS

Recent Discoveries: New Substances on Mars

NASA's ongoing missions have recently reported the discovery of new substances on Mars, particularly through the Perseverance rover and the Ingenuity helicopter. Perseverance, which landed on Mars in February 2021, has been tasked with seeking signs of ancient life and collecting rock and soil samples for future return to Earth.

1. Organic Molecules and Their Significance

One of the most groundbreaking discoveries from Perseverance has been the identification of organic molecules in Martian rocks. Organic molecules are carbon-based compounds that are often associated with life. Their presence does not confirm life on Mars but suggests that the building blocks of life may exist on the planet.

NASA scientists have detected these molecules using the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instrument, which utilizes advanced spectroscopy techniques to analyze the composition of rock samples. This discovery has revived discussions about the potential for past microbial life on Mars.

2. Salts and Their Geological Implications

Another significant finding from Perseverance is the presence of various salts in the Martian soil. These salts, including perchlorates, are of particular interest because they can provide insights into the planet's past climate and potential for habitability. Salts can indicate the presence of liquid water in the past, as they often form in evaporative environments.

The discovery of salts raises questions about the history of water on Mars. Understanding the distribution and concentration of these salts can help scientists reconstruct the planet's climatic history and assess whether conditions were ever suitable for life.

3. Unusual Rock Formations and Their Composition

Perseverance has also encountered unusual rock formations that suggest a complex geological history. These formations, characterized by unique textures and mineral compositions, may tell a story of past volcanic activity, sedimentation, and erosion.

Researchers are employing a variety of analytical techniques to understand the mineralogy of these rocks. The ChemCam instrument, which uses laser-induced breakdown spectroscopy, has been instrumental in identifying the elemental composition of Martian rocks, revealing a diverse geological landscape.

The Role of Ingenuity in Exploration

The Ingenuity helicopter, accompanying Perseverance, has demonstrated the feasibility of powered flight on another planet. Its successful flights have not only provided aerial perspectives of the Martian terrain but have also guided Perseverance to scientifically interesting locations.

Ingenuity's ability to scout the landscape has been invaluable in directing the rover to areas with promising geological features. This synergy between the two missions highlights the potential for innovative technologies in planetary exploration.

A photograph of a "Silver Mountain" rock sample collected by NASA's Perseverance Mars Rover as it explores the rim of Jezero Crater. 

(Image credit: NASA/JPL-Caltech)

Implications for Future Mars Missions

The discoveries made by Perseverance and Ingenuity have profound implications for future Mars exploration. As NASA plans for the Artemis program and aims to return humans to the Moon, the lessons learned from Mars missions will inform the agency's approach to exploring other celestial bodies.

1. Sample Return Missions

One of the most ambitious goals of the current Mars exploration program is the return of samples to Earth. The Mars Sample Return mission, a collaboration between NASA and the European Space Agency (ESA), aims to bring back rock and soil samples collected by Perseverance. Analyzing these samples in terrestrial laboratories could yield insights that are currently beyond our reach with remote sensing and in-situ analysis.

2. Search for Life

The discoveries of organic molecules and salts have intensified the search for life on Mars. Future missions will likely focus on identifying biosignatures—chemical indicators of past or present biological activity. This search will involve more sophisticated instruments capable of detecting and analyzing potential life forms, including microbial life.

3. Human Exploration

As NASA prepares for the eventual human exploration of Mars, understanding the planet's geology, climate, and potential hazards will be crucial. The presence of resources, such as water in the form of ice or brines, will play a significant role in sustaining human life on Mars. Future missions will prioritize the identification and assessment of these resources.

Public Interest and International Collaboration

The discoveries on Mars have also sparked renewed public interest in space exploration. NASA's commitment to transparency and engagement with the public has fostered a sense of excitement and curiosity about the Red Planet. Educational outreach programs and interactive platforms have allowed people worldwide to participate in the journey of discovery.

Moreover, international collaboration in space exploration has become increasingly important. As countries like China, the United Arab Emirates, and India launch their Mars missions, the sharing of data and findings can enhance our collective understanding of the planet. Collaborative efforts can also help address the challenges of planetary exploration, including technology development and resource allocation.

Conclusion

The recent discoveries of new substances on Mars mark a significant milestone in our exploration of the Red Planet. The identification of organic molecules, salts, and unique geological formations has profound implications for our understanding of Mars' past and its potential to support life.

As NASA and other space agencies continue their missions, the integration of innovative technologies and international collaboration will be key to unlocking the mysteries of Mars. The quest for knowledge about our neighboring planet is not only a scientific endeavor but also an opportunity to inspire future generations to explore the cosmos.

In the coming years, as we await the return of samples from Mars and prepare for human exploration, the discoveries made today will shape our understanding of life beyond Earth and our place in the universe. The journey to Mars is just beginning, and the excitement of discovery continues to propel us forward into the unknown.

{ PETER2011 }

14-02-2025 om 16:46 geschreven door peter  

Astronomers Just Discovered a New Dwarf Planet Beyond Neptune

Scientists think there were once many more of these dwarf planets in our Solar System, but most were destroyed or ejected when the larger planets in our Solar System moved to their current positions. But now RR245 joins the ranks of other survivors from this period – such as Ceres, Pluto, Haumea, Makemake, and Eris, which have all been recognised as dwarf planets by the International Astronomical Union – amidst the tens of thousands of much smaller objects beyond Neptune.

The researchers first spotted the dwarf planet in February, when astronomer JJ Kavelaars from the National Research Council of Canada was sifting through OSSOS data recorded in September 2015.

"There it was on the screen," said Bannister, "this dot of light moving so slowly that it had to be at least twice as far as Neptune from the Sun."

The team suggests it's possible that RR245 may be one of the last large worlds detected beyond Neptune with today's telescopes, as the brightest dwarf planets have already been mapped – although the debut of the Large Synoptic Survey Telescope next decade could turn up new discoveries we haven't been able to detect so far.

"OSSOS was designed to map the orbital structure of the outer Solar System to decipher its history," said one of the researchers, Brett Gladman of the University of British Columbia in Canada. "While not designed to efficiently detect dwarf planets, we're delighted to have found one on such an interesting orbit."

But beyond helping us map the outer reaches of our Solar System, the discovery of these dwarf planets – and their unique geological composition – helps us understand more about the cosmic past in our corner of the galaxy.

"They are the closest thing to a time capsule that transports us to the birth of the Solar System," astrophysicist Pedro Lacerda from Queen's University Belfast in Northern Ireland, who wasn't involved with the discovery, told Ian Sample at The Guardian. "You can make an analogy with fossils, which tell us about creatures long gone."

The discovery hasn't been published yet, so we're still waiting on further details from the researchers for now, but RR245 has been formally noted by the International Astronomical Union.

{ https://www.sciencealert.com/ }

13-02-2025 om 23:57 geschreven door peter  

• READ MORE: NASA makes 'emergency' decision as asteroid approaches Earth 

By WILIAM HUNTER

A terrifying new animation has revealed the projected path of the 'city-destroying' asteroid heading towards Earth. 

And it suggests that Earth isn't the only object in the firing line. 

According to Dr David Rankin, operations engineer for the University of Arizona's Catalina Sky Survey, the moon is also at risk of being hit. 

Dr Rankin calculated the route that the asteroid, 2024 YR4, is most likely to take.

His calculations indicate that 2024 YR4 currently has a 2.1 per cent, or one in 48, chance of colliding with Earth on December 22, 2032.

This is actually slightly less than previous estimates, which suggested there was a 2.3 per cent (one in 43) chance of impact.

Meanwhile, the scientist predicts there's a roughly 0.3 per cent (one in 333) chance of 2024 YR4 hitting the moon.

If the asteroid does hit Earth, the impact could release a blast of energy equivalent to 15 megatons of TNT - 100 times more powerful than the atomic bomb dropped on Hiroshima during World War II.

David Rankin, operations engineer for the University of Arizona's Catalina Sky Survey, calculated the route 2024 YR4 is most likely to take (white line). Showing the precise collision course which could lead to a deadly impact 

A terrifying new simulation reveals the path of the city-killer asteroid 2024 YR4 which has a 2.1 per cent probability of colliding with Earth in 2032

(stock image)

The asteroid was first detected by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) station in December last year.

It soon set alarm bells ringing as NASA almost doubled the probability of an impact with Earth from 1.2 per cent to 2.3 per cent.

Although that probability has now slightly decreased, 2024 YR4 is still the only large asteroid with an impact probability greater than one per cent - making it by far Earth's biggest threat.

However, Dr Rankin's calculations present a chilling new possibility that the asteroid could collide with the moon instead.

In a post on BlueSky, Dr Rankin revealed that there was a roughly 0.3 per cent chance of 2024 YR4 hitting the moon.

Without any atmosphere to slow its approach, the asteroid would slam into the lunar surface at a staggering speed of 31,000 miles per hour (50,000 kilometres per hour).

The collision would unleash an explosion 343 times the size of the atomic bomb dropped on Hiroshima and carve out a crater up to 1.2 miles (2km) across.

Should it hit the moon, it is most likely to land in the region stretching south from the Mare Crisium, a large plain of solidified lava, to the crater Tycho.

Asteroid 2024 YR4 is about the same size as the Tunguska asteroid, which caused the largest impact event in recorded history when it shot through Earth's atmosphere in 1908, flattening 830 square miles (2,150 square km) of forest (pictured)

Analysis of 2024 YR4's orbit indicates that the asteroid will most likely pass by Earth on December 22, 2032. However, new calculations suggest that it could also collide with the moon 

This could be concerning since this would place the impact on the side of the moon facing Earth, potentially exposing us to a shower of lunar shrapnel.

Thankfully, experts say that the Earth likely wouldn't be harmed by any impact which occurs on the moon.

Dr Rankin told New Scientist: 'There is the possibility this would eject some material back out that could hit the Earth, but I highly doubt it would cause any major threat.'

Unlike a large object such as 2024 YR4, these smaller pieces of debris should burn up harmlessly in the atmosphere creating nothing more than a particularly bright meteor shower.

In fact, some experts suggest that the collision between the asteroid and the moon could create a truly spectacular display.

Gareth Collins, a professor of planetary science at Imperial College London, told New Scientist: 'The impact flash of vaporised rock would be visible from Earth, even in the daytime.'

That means any keen stargazers on Earth could see the moment the asteroid detonates on the lunar surface with the naked eye.

However, it is currently seven times more likely to hit Earth rather than the moon. 

Without any atmosphere to slow it down, the asteroid would hit the moon at 31,000 miles per hour (50,000 kilometres per hour), creating an explosion bright enough to see from Earth with the naked eye 

These probabilities are likely to change in the future as scientists gather more information about the asteroid's orbit.

The current estimates for 2024 YR4's orbital path, speed, and size come from hundreds of images taken by powerful telescopes all around the world.

However, over such a short period of time, it is difficult to precisely predict where the asteroid will travel.

While astronomers hope that the probability of an impact will rapidly fall towards zero, a direct collision with Earth cannot be ruled out.  

Recently, NASA and the European Space Agency (ESA) made the emergency decision to use the James Webb Space Telescope (JWST) to take more accurate measurements.

The JWST will record the heat emitted by the asteroid using its infrared sensors which will give a more accurate estimate for its size.

A team of ESA scientists will make one observation in March when the asteroid reaches its peak brightness and another in May as it travels away from Earth.

This will be the last chance to observe 2024 YR4 before it becomes too dim to see from Earth until it returns again in 2028.

The European Space Agency has been given emergency access to the James Webb Space Telescope (pictured) to measure the asteroid's size more accurately 

Already, NASA has reached a hugely-important milestone with the DART asteroid deflection mission. In September 2022, the DART spacecraft was intentionally crashed into Dimorphos, an asteroid 6.8 million miles away. A similar method could be used to deflect asteroid 2024 YR4 before it reaches Earth 

Those observations will be critical for determining whether the world's space agencies need to take action to divert its course.

NASA's Double Asteroid Redirection Test (DART) mission demonstrated how a space rock could potentially be thrown off a collision course with Earth by crashing a spacecraft into it.

Using a similar strategy to knock 2024 YR4 off its predicted orbit is one possible way that planetary defence organisations could protect Earth.  

However, with only eight years until the asteroid arrives, some scientists have cast doubt on the plan to deflect the killer asteroid.

In a post on X, Dr Robin George Andrews, a volcanologist and author based in London, points out that we 'have less than eight years to potentially deal with it'.

'You need 10 years or more to build, plan and execute an asteroid deflection mission,' he said.

{ https://www.dailymail.co.uk/ }

13-02-2025 om 21:04 geschreven door peter  

'Stranded' Starliner astronauts finally have a return date — and it's sooner than expected

Related: 

• Boeing Starliner astronauts could spend nearly 300 days stuck in space — is that a new record?

As for the stranded pair, they have made the most of their time in orbit: Williams recently broke the record for the most nonconsecutive hours of spacewalking by a female astronaut.

A long-awaited homecoming

In December 2024, NASA announced that Williams and Wilmore would return on a newly designed SpaceX Dragon capsule in late March 2025 at the earliest. But now, the astronauts and the rest of Crew-9 will come home on a previously flown Dragon capsule, the Endurance. This will allow the swap between Crew-9 and Crew-10 to happen sooner while SpaceX continues to finalize the interior and final integration of the new Dragon capsule, according to NASA.

Along with Wilmore and Williams, astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov will leave the ISS in March. They'll be replaced by NASA astronauts Anne McClain and Nichole Ayers, Japan Aerospace Exploration Agency astronaut Takuya Onishi, and Roscosmos cosmonaut Kirill Peskov. The precise day of the return will be determined by weather conditions near Florida, where Endurance will splash down.

{ https://www.livescience.com/space }

13-02-2025 om 18:43 geschreven door peter  

Uranus’s Moon Ariel is Probably Hiding a Vast Ocean

"The size of Ariel's possible ocean and its depth beneath the surface can only be estimated..."

A photograph of Ariel.

Credit: NASA.

Unlike other surface features, these chasms appear to be the only structures facilitating material movement from Ariel’s interior, making them particularly valuable for future study.

Earth-Like Geological Processes at Work?

Scientists analyzing Ariel’s terrain have found striking similarities to a geological process observed on Earth known as spreading. This occurs along volcanic ridges where the seafloor slowly separates, allowing molten material to rise and form new crust.

On Ariel, a similar process could be unfolding as warmer material from the moon’s interior forces its way up, splitting the icy surface before filling the cracks. Researchers tested this theory by digitally aligning the two sides of Ariel’s chasms as if “zipping them back up,” and found a perfect match. The presence of parallel grooves along some chasm floors further supports the idea that material has been accumulating over time through repeated geological activity.

Could a Hidden Ocean Be Driving These Changes?

Another factor influencing Ariel’s surface could be gravitational interactions between Uranus and its moons. These interactions, known as orbital resonance, create internal heating that can melt ice and sustain liquid water beneath the crust.

Recent observations from the James Webb Space Telescope (JWST) provide compelling evidence that a hidden ocean may exist beneath Ariel’s surface. If so, this ocean might be responsible for the carbon dioxide deposits seen within the moon’s deep chasms. However, current data is insufficient to determine the exact size and depth of this possible ocean.

“The size of Ariel’s possible ocean and its depth beneath the surface can only be estimated, but it may be too isolated to interact with spreading centers,” Beddingfield explains.

Despite significant advancements in planetary exploration, much about Ariel remains unknown. While the Voyager 2 spacecraft provided valuable data during its 1986 flyby, it lacked the instruments needed to map the precise distribution of ices on the moon’s surface. Future missions with more advanced sensors will be crucial in determining whether Ariel is truly home to a hidden ocean—and what that might mean for our understanding of ocean worlds beyond Earth.

RELATED VIDEOS

{ https://curiosmos.com/category/space/ }

13-02-2025 om 18:07 geschreven door peter  

An illustration of a planet-killer asteroid.

Depositphotos.

Although further tracking will likely lower the impact probability, 2024 YR4 is a top priority for planetary defense experts.

2. Bennu

• Potential Impact Date: September 24, 2182
• Estimated Size: 490 meters
• Impact Probability: 1 in 2,700 (0.037%)
• Energy Release Upon Impact: Equivalent to 1.4 billion tons of TNT

Bennu is one of the most well-studied potentially hazardous asteroids, thanks to NASA’s OSIRIS-REx mission, which returned samples in 2023.

Although the impact probability is low, a collision would be catastrophic—releasing enough energy to cause continent-wide destruction and severe climate disruptions. NASA scientists continue to monitor Bennu to determine if future deflection strategies will be necessary.

3. 1950 DA

• Potential Impact Date: March 16, 2880
• Estimated Size: 1,300 meters
• Impact Probability: 1 in 34,500 (0.0029%)
• Energy Release Upon Impact: Equivalent to 75 billion tons of TNT

1950 DA is a massive asteroid that, despite its low impact probability, remains a serious long-term threat. If it were to hit Earth, it would cause global devastation—triggering tsunamis, firestorms, and potentially a planet-wide climate crisis.

Although the impact risk is expected to decrease with further observations, planetary defense programs continue to monitor this colossal object.

4. 2023 VD3

• Potential Impact Date: November 8, 2034
• Estimated Size: 11–24 meters
• Impact Probability: 1 in 387 (0.26%)
• Energy Release Upon Impact: Comparable to the Chelyabinsk meteor event

Although 2023 VD3 is much smaller than the other asteroids on this list, its relatively high impact probability makes it a major concern. With a 1 in 387 chance of impact in 2034, it has one of the highest statistical risks currently known.

While it wouldn’t cause a global disaster, an asteroid of this size could explode in the atmosphere, producing a shockwave strong enough to damage buildings and injure thousands—similar to the Chelyabinsk event in 2013, where a 20-meter asteroid caused widespread damage.

Further observations will determine whether 2023 VD3 will safely pass Earth or require further attention.

5. 1979 XB

• Potential Impact Date: December 14, 2113
• Estimated Size: 400–900 meters
• Impact Probability: 1 in 1.8 million (0.000055%)
• Energy Release Upon Impact: Equivalent to 30 billion tons of TNT

First observed in 1979, 1979 XB is one of the largest asteroids on the risk list. Because of its size, a collision with Earth would have severe global consequences, similar to the asteroid that wiped out the dinosaurs.

However, 1979 XB is classified as a lost asteroid, meaning its exact orbit is uncertain. Scientists are working to relocate it and refine its trajectory to confirm whether it poses a real long-term risk.

Can We Stop an Asteroid Impact?

While none of these asteroids pose an imminent danger, scientists are working on planetary defense strategies to ensure Earth’s safety.

• NASA’s DART Mission – Successfully altered an asteroid’s trajectory in 2022, proving that impact deflection is possible.
• Upcoming Space Missions – Future missions will explore gravity tractors, nuclear deflection, and other techniques to steer dangerous asteroids away from Earth.
• Advanced Tracking Systems – Telescopes like ATLAS, Pan-STARRS, and the Vera C. Rubin Observatory are improving our ability to detect threats decades in advance.

The likelihood of a catastrophic asteroid impact remains low, but continuous tracking is critical for ensuring early detection and possible deflection efforts.

Among all the asteroids being monitored, 2024 YR4 is the most immediate concern due to its relatively high impact probability in 2032. While ongoing observations will likely refine its trajectory, planetary defense experts are paying close attention—ensuring that if an asteroid ever truly threatens Earth, we’ll be ready.

RELATED VIDEOS

{ https://curiosmos.com/ }

13-02-2025 om 17:43 geschreven door peter  

Surprisingly, the lack of outside air pressure actually makes it easier to form a sphere than it would be on Earth since less pressure would be necessary to expand the sphere outwards. There are some nuances in the glass as well, with it being more like a glass lattice with embedded titanium or aluminum to make it stronger. Specific kinds of glass, such as borosilicate glass, could potentially add to the strength of the glass itself.

Most of the materials required to create such a structure could already be found on the lunar surface. Lunar regolith is full of the raw building materials required to make the structure work. Some of it has already been blasted into glass-like structures called agglutinates when micrometeoroids hit the lunar surface.

Those micrometeoroid impacts pose another risk to the glass sphere. Dr. Bermudez suggests having multiple layers of glass protecting the habitat, each with a layer of argon between them, like modern-day double-glazed windows. He suggests that spinning the outer layer might also provide some advantage, as will the spherical shape itself, as the impact force will dissipate better into the structure than it would on a flat surface.

Dr. Bermudez’s dreams don’t stop at the Moon, though. He suggests such a glass-blown structure could be useful on Mars or asteroids, where the microgravity would make it even easier to create these structures. On Mars, such a habitat might be limited to the top of Olympus Mons, where the atmosphere is thinner, and there isn’t as much wind and dust that could erode away the outer layers.

Many use cases exist for a structure like this, though many technical challenges remain. NIAC is the place for novel ideas that could potentially impact space exploration, and this one certainly fits that bill. As Dr. Bermudez works through de-risking his design, we get closer than ever to a future of aesthetically pleasing habitats on the Moon and everywhere else in the solar system.

Learn More:

• NASA / Martin Bermudez – Lunar Glass Structure (LUNGS): Enabling Construction of Monolithic Habitats in Low-Gravity
• UT – Glass Fibers in Lunar Regolith Could Help Build Structures on the Moon
• UT – Recreating the Extreme Forces of an Asteroid Impact in the Lab
• UT – Conceptual Design for a Lunar Habitat

Lead Image:

• Artist’s concept of a lunar sphere on the lunar surface.
• Credit – NASA / Martin Bermudez

{ https://www.universetoday.com/ }

13-02-2025 om 17:14 geschreven door peter