Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: diverjohn on 13/10/2016 00:04:59
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Scientists have shown that some meteorites found on earth originated on Mars, likely ejected after a meteoric impact on the red planet.
So, how likely is it that after the meteor that crashed into Mexico 65 million years ago
Ejected material may have reached Mars if the two planets were close to one another around the time of impact?
It would make great science fiction if bits of dinosaur or mammalian flesh landed in a warm puddle of water on another planet and started growing.
Love your show!
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... It would make great science fiction if bits of dinosaur or mammalian flesh landed in a warm puddle of water on another planet and started growing ...
Someone has beat you to that ... https://en.wikipedia.org/wiki/Panspermia#Science_fiction
I have difficulty believing any living thing could survive the acceleration required to reach escape velocity (https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape_velocities) in a split-second , but apparently it is possible (https://en.wikipedia.org/wiki/G-force#Other_biological_responses).
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how likely is it that after the meteor that crashed into Mexico 65 million years ago ejected material may have reached Mars?
It is much easier to blast something off Mars and have it land on Earth than the reverse.
- Mars has lighter gravity
- Mars has a much thinner atmosphere
- Ejected debris are more likely to escape Mars without being slowed significantly by the atmosphere
- Ejected debris passing through the atmosphere of Mars are more likely to reach the escape velocity of Mars.
So I would never say it is impossible for Earth rocks to reach Mars, but they will probably be rarer than Mars rocks reaching Earth.
Earth does have the disadvantage that it is 70% covered by water, and plate tectonics regularly resurfaces the planet. Neither of these seems to be active on Mars at present.
if the two planets were close to one another around the time of impact?
The lowest-energy orbit to go from Earth to Mars (the Hohman Transfer Orbit) actually reaches the orbit of Mars when it is on the opposite side of the Sun from where it was ejected. So being "close" is not a real requirement.
The odds are that Mars would not be at that location when the rocks arrived, but if these rocks have enough energy to cross from the orbit of Earth to Mars, they will keep on that elliptical orbit until they are deflected by Earth or Mars or Moon, or strike one of these bodies. It could take millions of years.
See: https://en.wikipedia.org/wiki/Hohmann_transfer_orbit#Application_to_interplanetary_travel
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Thanks for the replies and opinions on earth life surviving a blast to mars.
Seems only a hardy bacteria deep in a rock could survive, then only if it were very lucky to avoid being fried by the heat of the impact.
So no Tyrannosaurs on Mars.
However, there is worry from space scientists about germs hiding on Martian landers and rovers that may thrive in a wet pocket of red soil, thereby causing onboard sensors to detect life that wasn't indigenous.