WARNING: Wild speculation required: If an instellar comet had a core from a life-beaing planet?

Question

that broke free from a Giant Impact (like the one that made our moon - only more violent ) could a single strand of DNA be preserved in it indefinitely?

Answer 1

No wild speculation needed.

We have antarctic ice cores going back some eight million years.  Bacteria even a million years old can often be brought back to life by exposing it to warmth and nutrients. But as you go back the DNA is more and more damaged, limiting the amount of time  you can go back.  On the one hand, Antarctica is beneath the Earth's magnetic field, shielding it from cosmic rays and other nasty radiation.  And there was a mile of ice over some of it.  But the magnetic field at the pole does not protect quite as well as on the rest of the Earth.

It appears that the time required for a life bearing rock to get from one star to another is too long, and it would end up being sterilized by the time it reached it's destination.

If one posits that life on Earth started on a planet around another star, it just pushes back the origin of life to somewhere else.  We'd still want to know how it got started.  Same with God.  If God created it, where did God come from?

Answer 2

not likely, conditions in space make it very unlikely.

Answer 3

I'm guessing no.  Cosmic radiation alone would degrade any DNA molecules over time.  And I'm guessing long exposure to 3 degree K temperatures wouldn't help either.  But bacteria spores from earth did survive quite happily on the moon for several years, so Perhaps such survival, especially in the subsurface, might just be possible.  I seem to be covering all bases here.  Sorry.

Answer 4

Basic elements are preserved on comets. But organic matter? The conditions on a comet are so extreme and hostile to life that I wildly speculate that the organic matter would not survive.

Answer 5

DNA preserves poorly in general and space makes it significantly harder to survive.