[malakhi]

Gravitational, due to close pass-by. (It doesn't have to be all that close with bodies as large as Mars and Earth.)

Mars and Earth never get that close; the gravitational influence between the two planets is negligible.

[D Rider]

Mars and Earth never get that close; the gravitational influence between the two planets is negligible.

No kidding. Could that be because of the altered orbits, they were talking about then, hmmm?

Anyway, thanks for the tip, I had never noticed before. /sarcasm.