I've heard about a scenario where Jupiter once wreaked havoc on the orbits of the inner planets, pushing some of them closer to the Sun and pulling others further away. (It's not the Nice model [1] but some unorthodox variation of it.)
Could Mars have been closer to the Sun when this lake existed (3.5 billion years ago), or is that too late in the history of the Solar System for any major disturbance to have happened?
I think you're refering to the Grand tack hypothesis[0], but Wikipedia is scarce on details as to how that scenario could've affected Mars orbit.
I was trying to see if this had a timeline, because the NASA cites lack of CO2 as far as -3.5GY, but there isn't enough detail in Wikipedia and my 5 minutes slack time is over :(
Is it possible that other greenhouse gasses than CO2 were present that helped keep water liquid? Or maybe the planet produced enough internal heat to warm up the surface beyond freezing? Or atmosphere, whatever it was, was thick enougj to produce high pressures that kept water liquid despite freezing temperatures?
Surely if water was liquid and CO2 was not there, those must be the only possible scenarios? Or a combination of them, of course.
How about water? It's a more potent greenhouse gas than CO2. I'm aware that the suggestion presents another mystery, but at least it's an obvious greenhouse gas that was present on Mars.
Methane is more potent than CO2, but fairly short lived. Maybe Mars had more Methane in the distant past? If a 95% CO2 atmosphere isn't enough green house gas for liquid water, I'd assume internal heat played some sort of role.
My guess is methane as well, Mars still "breathes" out methane occasionally[1]. Given that chunks of Mars have been kicked off the planet and landed on Earth, I wonder if you modeled a chunk of Titan's methane ice being kicked off Titan and hitting Mars would have the effect of filling out enough of Mars' atmosphere to warm it.
Could Mars have been closer to the Sun when this lake existed (3.5 billion years ago), or is that too late in the history of the Solar System for any major disturbance to have happened?
[1] https://en.wikipedia.org/wiki/Nice_model