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It is very likely life on earth evolved under more optimal conditions and then adapted to drier and more extreme ones. Was Mars ever hospitable enough for long

It is very likely life on earth evolved under more optimal conditions and then adapted to drier and more extreme ones. Was Mars ever hospitable enough for long enough for life to evolve is the question.

thriftwy 9y ago
Nope! First signs of life are found on Earth in very early minerals that existed under extremely brutal conditions back then. They're also found in oldest parta of crust that we have.
- blkhawk 9y ago
  well, AFAIK we still have no idea whats actually needed for life to form. Also the conditions for life were better on mars in the past so its entirely possible that life existed and kept on going on mars.
labster 9y ago
Nah. The question is if life could feasibly hop from a meteor impact on Earth over to Mars.
- seszett 9y ago
  That is a lot less likely than the other way round, as the atmosphere of Earth and its greater proximity to the Sun makes it immensely more difficult to launch a rock from the surface all the way to Mars. While a rock launched from the surface of Mars, once it has escaped the planet's gravity well without encountering significant drag from the atmosphere, can just "fall" to Earth.
  - Symmetry 9y ago
    Gaining and losing orbital energy are both equally hard in the vacuum of space, it's not harder to get from Earth's orbit around the Sun to Mars's or vice-versa - though it takes somewhat different amounts of delta-v to go to an Earth-Mars intercept from them. The reason it's easier for ejecta to get from Mars to Earth than vice versa is that Mars has a shallower gravity well to climb out of before making the inter-planetary trip. It's a lot easier for an impact to impart the ~6 km/s velocity you need to get from the surface of Mars to hitting Earth's atmosphere than the ~13 km/s it takes to get from Earth's surface to hitting Mars.

3 ms·

It is very likely life on earth evolved under more optimal conditions and then adapted to drier and more extreme ones. Was Mars ever hospitable enough for long

by JohnJamesRambo 9y ago

thriftwy 9y ago
Nope! First signs of life are found on Earth in very early minerals that existed under extremely brutal conditions back then. They're also found in oldest parta of crust that we have.
- blkhawk 9y ago
  well, AFAIK we still have no idea whats actually needed for life to form. Also the conditions for life were better on mars in the past so its entirely possible that life existed and kept on going on mars.
labster 9y ago
Nah. The question is if life could feasibly hop from a meteor impact on Earth over to Mars.
- seszett 9y ago
  That is a lot less likely than the other way round, as the atmosphere of Earth and its greater proximity to the Sun makes it immensely more difficult to launch a rock from the surface all the way to Mars. While a rock launched from the surface of Mars, once it has escaped the planet's gravity well without encountering significant drag from the atmosphere, can just "fall" to Earth.
  - Symmetry 9y ago
    Gaining and losing orbital energy are both equally hard in the vacuum of space, it's not harder to get from Earth's orbit around the Sun to Mars's or vice-versa - though it takes somewhat different amounts of delta-v to go to an Earth-Mars intercept from them. The reason it's easier for ejecta to get from Mars to Earth than vice versa is that Mars has a shallower gravity well to climb out of before making the inter-planetary trip. It's a lot easier for an impact to impart the ~6 km/s velocity you need to get from the surface of Mars to hitting Earth's atmosphere than the ~13 km/s it takes to get from Earth's surface to hitting Mars.