4 ms·

I thought meteorite transfer was one-way... Mars to Earth.

• fsloth 8y ago
  Why? It seems to me the requirement is to have a mass with escape velocity from the parent body, and then have it’s orbit intercept another. The delta v required for the latter is symmetrical, from mars to earth. Hence, if a rock reaches escape velocity it would seem to me to be as easy to have pieces of earth rain on mars as it is to have mars fragments rain on earth. The impact on earth to cause ejecta to have escape velocity would probably need to be larger than on mars.
  • knodi123 8y ago
    > The impact on earth to cause ejecta to have escape velocity would probably need to be larger than on mars. significantly larger, because it has to get through our atmosphere once on the way in, and then the ejecta has to do it again on the way out, keeping in mind that drag is proportional to velocity squared, and that whatever ejecta is making this trip has to find a way not to get cooked into sterility by impact energy or friction with the air.... Too many extra factors are in play, each of which adds an exponent to the unlikelihood. But that's just my uneducated opinion, I'm certainly open to discussion.
  • simonh 8y ago
    The dV to get off Mars and to interplanetary transfer is about half that from Earth. I would expect the ejection energy of impact debris particles to scale with the square root of the impact energy, so you'd need four times the impact energy on Earth to achieve the same level of debris ejection as on Mars, and that's not counting the effect of Earth's atmosphere on cushioning and ameliorating such impacts. The dV to then end up on either planet doesn't matter because aerobraking and lithobraking do all the work for you.
• thaumasiotes 8y ago
  Why? Earth gets hit by large meteors just like Mars does.