[curmudgeonII]

This theory was promoted about a century ago by Arrhenius. Although it obviates stewing about the origin of life on earth, it really begs the question as it brings about the question, How did life originate on planet X

[who_would_fardels_bear]

"How did life originate on planet X"

That's any easy one.

In the future, super-intelligent androids from our planet will build a time machine so they can go back and seed the original planets with living matter.

[metmom]

How did life originate on planet X

Well, that life was seeded from planet W, whose life was seeded from planet V, and so it goes....

If they keep pushing it back far enough, they can maybe ignore that life cannot spontaneously arise from non-living matter (spontaneous generation) and can avoid that complicating little factor.