Mars gets somewhat nice

In about 1.6 billion years, the sun's habitable zone will have moved outward, increasing the carbon dioxide in Mars's atmosphere. According to Wikipedia, its surface temperature will rise "to levels akin to Earth during the ice age".

Combining a thick carbon dioxide layer to trap the heat (and the atmosphere), and the future extent of the habitable zone of the sun which will continue to warm the planet, it's reasonable to think that the Martian ice caps will melt - filling the northern, low-lying plains, and creating a primitive ocean. Assume, for this question, that that happens, 1.8 billion years from now, and that the atmosphere won't leave for billions more years.

BOOM! Panspermia occurs.

The Earth, now desolate and devoid of humans, is hit by something large (it'll happen eventually), throwing material into orbit, along with some hitchhikers. You are free to choose what exactly is on this material, but it should be able to survive a trip through space to the Martian ocean. Consider an extremophile organism, or a tardigrade, or a newly evolved something, which thrives the hot-Earth present.

That material lands in the sea, and life starts to evolve based on whatever just came from Earth;

Which organisms will survive, and what traits will start to develop among the population(s)?

Can a complex ecosystem eventually be built upon this?

  • $\begingroup$ A) Panspermia may have already occurred during KT Event, so answers might want to account for older stuff. B) NASA et. al. cleans our probes today well, but something might get through from current day, waiting for Mars atmosphere to develop. ... This isn't an answer, just two points for answers to contemplate. $\endgroup$
    – SRM
    Commented Jan 2, 2017 at 15:54
  • $\begingroup$ IIRC Mars doesn't have (meaningful) atmosphere because it's core went cold and magnetosphere disappeared. I doubt it can develop atmosphere again without somehow liquefying and spinning the core. $\endgroup$
    – M i ech
    Commented Jan 2, 2017 at 17:12
  • $\begingroup$ Unlikely to work with Mars, because the stronger sun radiation will make it loose it's new atmosphere faster than developing it. Generally, a handful of different earth microbes can contain a huge amount of (dormant) genetic traits that would lend hand to an evolution in fast-forward mode, possibly surprisingly similar to the earth biosphere. $\endgroup$
    – Karl
    Commented Jan 2, 2017 at 17:27
  • $\begingroup$ @Miech It can develop rapidly through melting and bombardments; it can't stay but that doesn't mean it won't work for a small period. $\endgroup$
    – Zxyrra
    Commented Jan 2, 2017 at 17:27

1 Answer 1


It won't

This doesn't matter. Life on earth started 3.8 billion years ago and the Cambrian explosion was only 530 million years ago. that's a 2.3 billion year difference. so by the time the Martian equivalent of the Cambrian explosion will take place in 4.1 billion years.

Whoopsie daisy! That may be a problem, because in only 4 billion years Andromeda will crash into the Milky Way. Though there is a hope, because we do not know if Earth life evolution is average or not, so we may have been slow. So to answer your question, we will ignore this, we will also ignore that the heating of Mars to the level you want will likely wipe out Earth life. We need to use a bit of handwavium as well, because a blast large enough to send debris from Earth to Mars(an average of 225 million km) would superheat said debris.

Unfortunately, the question then becomes really broad at best. Saying we have a choice of what is on the debris means that you asking for which organisms will survive, and what traits will start to develop among the populations is dependent on the things on said debris. that combined with the fact that the 1.8 billion year gap if way too long in evolutionary terms to even guess what life on this future Earth will look like. Assuming;

  1. They don'y all die in the massive environmental change Earth goes through in the future, which is fairly probable.

  2. The Andromeda collision doesn't happen, which can be explained in an alternate universe.

  3. The massive crater impact doesn't kill them, which means they need to be small.

  4. The superheating of the ground beneath them as it shoots off into space lets them live, which I don't even think is remotely possible.

  5. The very logn journey through high pressure, super cold, airless, water-less, food-less space doesn't annihilate them.

  6. The reheating of said rock as it enters Mars' atmosphere doesn't burn them.

  7. And they find food, water and shelter wherever they land.

Ignoring all of these, you best answer is, what ever you want them to look like. Because we cannot even predict what they will look like when they are sent away never mind how they will adapt to this new Mars.

  • 1
    $\begingroup$ Andromeda collision is a non-issue; it is not expected to have any meaningful effect on the solar system itself, only the position of our Sun within our galaxy. Space, including galaxies, is mostly empty; galaxies "colliding" doesn't mean that any solar systems collide - at worst, the Sun would be ejected from the galaxy with no meaningful changes affecting the planets. However, during that time the Sun will become more active and yes, life on Earth will not be possible. $\endgroup$
    – Peteris
    Commented Jan 3, 2017 at 4:56
  • $\begingroup$ @Peteris plus, I imagine the Dark matter inbetween said galaxies would be a problem to $\endgroup$
    – TrEs-2b
    Commented Jan 3, 2017 at 5:00
  • $\begingroup$ @TinyTrEs-2b Do we even know enough about dark matter to guess as to its impact on such a relatively small scale? $\endgroup$
    – Jax
    Commented Jan 3, 2017 at 5:58
  • 2
    $\begingroup$ @DJMethaneMan considering it makes up over 50% of the mass of our galaxy, I'd say it has some effect $\endgroup$
    – TrEs-2b
    Commented Jan 3, 2017 at 6:25
  • $\begingroup$ @TinyTrEs-2b I am sure, but since we don't know almost anything about it other than how it very generally affects the universe, we would be hard-pressed to make any realistic judgements on how that would impact habitability, orbits, etc. We can probably safely discard it for purposes of this question. $\endgroup$
    – Jax
    Commented Jan 3, 2017 at 6:37

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