Extraterrestrial Origins Of Life on Earth

Hi straggler.The Murchison meteorite and its chemistry are actually old news, but that doesn’t change its interesting features. It could have brought traces of life from Mars to Earth, but the evidence is slim and disputed.One point I wish to make that is relevant here concerns the necessity of a life-bearing planet to have an atmosphere. From what I know of such things, Mars does not have a life-bearing atmosphere because its magnetic properties were insufficient to make a shield against the solar winds, and any atmosphere it tried to form may have been blow away. Thomas Gold, a free-thinking astrophysicist, hypothesized that Earth may contain two biospheres: one at its surface, which includes our atmosphere, and one existing about 15 km below the surface. In his book, “The Deep Hot Biosphere,” he argues that life could exist in the crusts of planets even if they didn’t have atmospheres. The organisms surviving “the deep hot biosphere” would have adapted to tremendous heat and pressure. At first blush it seems ridiculous from what we know about organic molecules under sever heat and pressure, but Gold offers some interesting thoughts on the matter.My point here is that we assume that life popped out of some special organic soup on the surface of bio-friendly Earth. And we want so badly to believe that abiogenesis happened only here. But Gold offers fresh ideas on the matter that may be useful to those who think about alternative biospheres that have influenced the evolution of life on Earth.Thomas Gold's thinking suggests to me that an extraterrestrial origin of life is even more plausible. Humans are naturally geocentric about our planet's role in the universe, until some sort of Copernicus comes along to change our minds.”HM

Chirality suggests to me a single origin of life, rather than a multi-regional outbreak. But it suggests nothing about where that single origin occurred. If it happened extra-terrestrially and migrated to Earth, then we are caught by Mr Jack's assertion that organic molecules with chirality couldn't survive a panspermatic impact.On the other hand, a rare survival can't be ruled out, given what little we know about abiogenesis.”HM

Good point! The theory of abiogenic petroleum origin is friendly to your POV.”HM