The widespread evidence for water on Mars, especially at the site now being explored by the Curiosity rover, seems very much at odds with what the geology tells us about the early Martian atmosphere.

Universe Today takes up the story:

The study of Mars’ surface and atmosphere has unlocked some ancient secrets. Thanks to the efforts of the Curiosity rover and other missions, scientists are now aware of the fact that water once flowed on Mars and that the planet had a denser atmosphere. They have also been able to deduce what mechanics led to this atmosphere being depleted, which turned it into the cold, desiccated environment we see there today.

At the same time though, it has led to a rather intriguing paradox. Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today. This would require that the Martian atmosphere had ample carbon dioxide in order to keep its surface warm enough. But based on the Curiosity rover’s latest findings, this doesn’t appear to be the case.

These findings were part of an analysis of data taken by the Curiosity’s Chemistry and Mineralogy X-ray Diffraction (CheMin) instrument, which has been used to study the mineral content of drill samples in the Gale Crater. The results of this analysis were recently published in Proceedings of the National Academy of Science, where the research team indicated that no traces of carbonates were found in any samples taken from the ancient lake bed.

…….“We’ve been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined. It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us.”

Full report, quite intriguing

Note that the same paradox applies to Earth.

dv said:

Note that the same paradox applies to Earth.

Could it be that internal energy sources make a greater contribution than the models suppose?

The Rev Dodgson said:

dv said:

Note that the same paradox applies to Earth.

Could it be that internal energy sources make a greater contribution than the models suppose?

Could be a lot of things.

I’m not going to do better than the WP article:

https://en.wikipedia.org/wiki/Faint_young_Sun_paradox

dv said:

The Rev Dodgson said:

dv said:

Note that the same paradox applies to Earth.

Could it be that internal energy sources make a greater contribution than the models suppose?

Could be a lot of things.

I’m not going to do better than the WP article:

https://en.wikipedia.org/wiki/Faint_young_Sun_paradox

OK, so the only obvious possibility not discussed there is the solar energy input being greater than thought.

What about other gases creating a green house effect and they didn’t leave much or any imprint on the geology

The Rev Dodgson said:

dv said:

The Rev Dodgson said:

Could it be that internal energy sources make a greater contribution than the models suppose?

Could be a lot of things.

I’m not going to do better than the WP article:

https://en.wikipedia.org/wiki/Faint_young_Sun_paradox

OK, so the only obvious possibility not discussed there is the solar energy input being greater than thought.

Those astrophysicists are so arrogant!

Cymek said:

What about other gases creating a green house effect and they didn’t leave much or any imprint on the geology

yep

dv said:

Note that the same paradox applies to Earth.

You’re right.

One thing though

“At the same time though, it has led to a rather intriguing paradox. Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today. “

Other resources on this topic say that Sun was *two*-thirds as warm as it is today.

dv said:

One thing though

“At the same time though, it has led to a rather intriguing paradox. Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today. “

Other resources on this topic say that Sun was *two*-thirds as warm as it is today.

Yes they presumably meant a third less warm.

Bubblecar said:

dv said:

One thing though

“At the same time though, it has led to a rather intriguing paradox. Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today. “

Other resources on this topic say that Sun was *two*-thirds as warm as it is today.

Yes they presumably meant a third less warm.

Wikipedia says 70% as intense compared to today

Some super computer modeling of different atmospheres/ elements / gravity etc is needed.

Do certain types of rocks/minerals absorb atmospheric gases significantly differently, so for example one area shows only 1% whilst another could show many times this percentage and you need samples from numerous places to get a estimate.

> Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today.

Believed by who?

Not true, according to the book “planetary sciences” by de Pater and Lissauer.