Thanks for that, still wonder if it is possible for a large celestial object to knock a planet onto a new orbit....
i watched the old TV series From The Earth To The Moon last month, unbelievable what man has achieved in such a short period. Since then every time I stand staring at the moon, I look at it in a different light.... so much out there to conquer.....
Not exactly, would be the answer to your first question. A celestial body that is large enough to "knock" a planet off of its orbit, is sure to obliterate the planet and itself in the process. But larger planets like Jupiter, can slingshot other planets about. As long as they don't touch, they would stay intact.
The most likely history of Mars, as far as self contained life is concerned. Is that is possibly had microbes, and even slightly more complex organisms. But nothing more than that before it lost the ability to sustain life. (That is following the hypothesis that life as we know it is a fairly common and inevitable occurrence in the universe, if given similar working conditions to Earth)
So if life is common, and Mars cooled before earth did, and had all of the necessary ingredients to propagate life. Then Mars likely had life of some very simple kind, long before we did. And it expired long before our planet's life forms even left the micro stage.
*Point to Ponder, the next time you get Drunxistential.
If life is a fairly common thing. And the main things it needs to be able to reach some kind of sentience like us humans, is to have a strong enough magnetosphere to protect the fragile lifeforms. Then imagine this. In the infinity of space, somewhere out there, there are possibly two planets, orbiting the same star. Both of which have advanced life. Both of whom, can actually definitely answer the question, "Are we alone in the universe". As they peer across a short gap in space, at one another.