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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
by 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 agoGaining 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.