Posted on 05/26/2022 8:27:59 AM PDT by LibWhacker
Billions of years ago, a river flowed across this scene in a Mars valley called Mawrth Vallis. A new study examines the tracks of Martian rivers to see what they can reveal about the history of the planet’s water and atmosphere. Credit: NASA/JPL Caltech/University of Arizona Mars once ran red with rivers. The telltale tracks of past rivers, streams and lakes are visible today all over the planet. But about three billion years ago, they all dried up—and no one knows why.
"People have put forward different ideas, but we're not sure what caused the climate to change so dramatically," said University of Chicago geophysical scientist Edwin Kite. "We'd really like to understand, especially because it's the only planet we definitely know changed from habitable to uninhabitable."
Kite is the first author of a new study that examines the tracks of Martian rivers to see what they can reveal about the history of the planet's water and atmosphere.
Previously, many scientists had assumed that losing carbon dioxide from the atmosphere, which helped to keep Mars warm, caused the trouble. But the new findings, published May 25 in Science Advances, suggest that the change was caused by the loss of some other important ingredient that maintained the planet warm enough for running water.
But we still don't know what it is.
Water, water everywhere, and not a drop to drink
In 1972, scientists were astonished to see pictures from NASA's Mariner 9 mission as it circled Mars from orbit. The photos revealed a landscape full of riverbeds—evidence that the planet once had plenty of liquid water, even though it's dry as a bone today.
Since Mars doesn't have tectonic plates to shift and bury the rock over time, ancient river tracks still lie on the surface like evidence abandoned in a hurry.
This allowed Kite and his collaborators, including University of Chicago graduate student Bowen Fan as well as scientists from the Smithsonian Institution, Planetary Science Institute, California Institute of Technology Jet Propulsion Laboratory, and Aeolis Research, to analyze maps based on thousands of pictures taken from orbit by satellites. Based on which tracks overlap which, and how weathered they are, the team pieced together a timeline of how river activity changed in elevation and latitude over billions of years.
Then they could combine that with simulations of different climate conditions, and see which matched best.
For years, researchers have debated whether Mars once even had enough water to form an ocean, as depicted in this concept illustration. Credit: NASA/GSFC Planetary climates are enormously complex, with many, many variables to account for—especially if you want to keep your planet in the "Goldilocks" zone where it's exactly warm enough for water to be liquid but not so hot that it boils. Heat can come from a planet's sun, but it has to be near enough to receive radiation but not so near that the radiation strips away the atmosphere. Greenhouse gases, such as carbon dioxide and methane, can trap heat near a planet's surface. Water itself plays a role, too; it can exist as clouds in the atmosphere or as snow and ice on the surface. Snowcaps tend to act as a mirror to reflect away sunlight back into space, but clouds can either trap or reflect away light, depending on their height and composition.
Kite and his collaborators ran many different combinations of these factors in their simulations, looking for conditions that could cause the planet to be warm enough for at least some liquid water to exist in rivers for more than billion years—but then abruptly lose it.
But as they compared different simulations, they saw something surprising. Changing the amount of carbon dioxide in the atmosphere didn't change the outcome. That is, the driving force of the change didn't seem to be carbon dioxide.
"Carbon dioxide is a strong greenhouse gas, so it really was the leading candidate to explain the drying out of Mars," said Kite, an expert on the climates of other worlds. "But these results suggest it's not so simple."
There are several alternative options. The new evidence fits nicely with a scenario, suggested in a 2021 study from Kite, where a layer of thin, icy clouds high in Mars' atmosphere acts like translucent greenhouse glass, trapping heat. Other scientists have suggested that if hydrogen was released from the planet's interior, it could have interacted with carbon dioxide in the atmosphere to absorb infrared light and warm the planet.
"We don't know what this factor is, but we need a lot of it to have existed to explain the results," Kite said.
There are a number of ways to try to narrow down the possible factors; the team suggests several possible tests for NASA's Perseverance rover to perform that could reveal clues.
Kite and colleague Sasha Warren are also part of the science team that will be directing NASA's Curiosity Mars rover to search for clues about why Mars dried out. They hope that these efforts, as well as measurements from Perseverance, can provide additional clues to the puzzle.
On Earth, many forces have combined to keep the conditions remarkably stable for millions of years. But other planets may not be so lucky. One of the many questions scientists have about other planets is exactly how lucky we are—that is, how often this confluence exists occurs in the universe. They hope that studying what happened to other planets, such as Mars, can yield clues about planetary climates and how many other planets out there might be habitable.
"It's really striking that we have this puzzle right next door, and yet we're still not sure how to explain it," said Kite.
Wind erosion and water erosion look quite similar. Now throw in extreme temperature fluctuations.
“It has no magnetic field, so the solar winds just evaporated the water away.”
The water didn’t simply evaporate. It froze. However, at some point the surface temperature was high enough to have running liquid water, at least for some portion of every year, and this happened for longer than it should have taken the solar wind to give Mars the atmosphere it currently has. Unless our prevailing geological models or something else are not quite right.
“Wind erosion and water erosion look quite similar.”
Sure, in some cases, and with a casual examination. But not in all cases, and not when examined closely by scientists who know the difference.
“started trapping all their Carbon Dioxide”
One problem with this speculation by the scientists that loss of CO2 caused it, is that the Martian atmosphere is still 95% CO2. So if Mars was losing CO2, it apparently wasn’t losing it any faster than it was losing the rest of its atmosphere.
Mars was robbed, by interplanetary travelers who thought that the Earth needed more water, and so, they set about transferring the water from Mars to Earth, which is all documented in the great flood in the bible.
I’m increasingly skeptical of university trained ‘scientists’. There seems to always be an agenda.
The low gravity of Mars along with the its loss of a magnetic field probably contributed to some of the water loss from the planet. There may still be some ice well beneath Mars’ surface.
BTW, when they say "water," do they mean H2O or any type of liquid?
And how would they know what type of liquid Mars had?
So evil human beings don’t have to be involved to get climate change? Huh.
“Plus, they’ve mapped our oceans, they are just keeping the findings secret because they think you can’t handle the truth.”
The inhabitants of Atlantis don’t want to be bothered by a bunch of tourists. They have an understanding with our Deep State, because the Atlanteans are the original Deepest State.
Water was deposited on Mars when it was expelled from Uranus.
Republicans driving SUVs is the only explantion.
There once was a rocky, water-world in the orbital space between Mars and Jupiter. It was a bit larger than Earth. and had quite a lot of liquid water. It was struck with one of the small-ish remaining “planetesimals” left over from the solar system’s formation.
The world was shattered from the collision, and the resulting debris formed the asteroid belt, and birthed numerous comets, many as messy mixtures of rocks, dust and water.
The planet seeded all the other planets with comets, stony and iron-y meteors, and watery comets.
Earth retained a lot of its water deposit. Being smaller, and not having a protective magnetic field, Mars’ lower gravity and exposure to the solar wind bled off its atmosphere and water allotment before large-scale life could develop.
On the other planets, the influx of meteors and wet comets made little difference, and was quickly absorbed without much effect.
It is possible that ruptured ocean-world had a civilization before it was destroyed.
I call it “Atlantis.”
Did not read article.
I suspect however, it was all the Martian SUVs that they were driving. Global Martian Warming. Evil Martians! They must have been conservatives!
</sarc>
Mars dried up because their MASA (Mars Aeronautics and Space Administration) funding ran out.
Mars has an inner metal core similar to Earth which early on granted Mars a sizeable magnetic field. However due to it’s much smaller size and further distance from the Sun, the core cooled down and it lost the magnetic field.
Earth’s strong magnetic field protects the atmosphere from solar radiation. Without it, this radiation would blast our atmosphere out into space. This is what happened to Mars.
Mars probably had a thicker atmosphere at one time that allowed for liquid water, but as the atmosphere was destroyed by the Sun, the water both evaporated into space and froze in the soil.
Know this, Mars can never be terraformed, because we can’t make the core molten and spinning. So just laugh when you see all these goofy millenials and gen Z ignoramouses put all their hopes and dreams into terraforming Mars for humans to colonize.
Well that’s a theory all right. My understanding of the asteroid belt is that Jupiter and Mars created a tug of war that keeps the objects in the belt from coalescing. It’s the same reason that some of the rings of Saturn don’t form more moons, as its own moon system shepherds the rings into their stability.
Scientists trying to figure out what happened one billion years ago to a planet 140 million miles away.
Scientists are starting to annoy me.
And the canals. I TOLD you people there were canals but would anybody listen? The question is what happened to all the gondoliers, isn't it? Did they all migrate to Venice?
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