Ophiolite
Valued Senior Member
No evidence?1. The appearance of comparatively complex lifeforms on the Earth almost as soon as the Late Heavy Bombardment period had ended.@Rob --
You do realize that there's literally no evidence supporting a Panspermia origin of life, right? It's a hypothesis, but not a very likely one and not a very respected one.
2. Modelling supporting the easy transfer of lifeforms from Mars to Earth.
3. The presence of scores of organic molecules in GMCs, accompanied by abundant substrates for chemical reaction.
Not a respected hypothesis?
Francis Crick found it respectable enough. (But then we know Nobel laureates get weird when they get older. Right?)
Here are some typical papers on the topic from hundreds that are available:
Survival of bacteria exposed to extreme acceleration:
implications for panspermia
Maximum Number of Habitable Planets at the Time of Earth's Origin: New Hints for Panspermia?
The enigma of the origin of life and its timing
And here is the abstract of a review article:
"Panspermia is the idea that life migrates naturally through space. Although an old idea, there has been much recent theoretical and experimental work developing the idea in recent years. In this review, this progress is considered and placed in context. Ideas concerning Panspermia now include mathematical treatments of the likelihood of transfer of life from Mars to Earth, the possibility of life transferring between the natural satellites of an outer planet such as Jupiter, and mathematical treatments and models of life migrating out of a Solar System. Not all predictions of the likelihood of successful Panspermia are positive, and some are contradictory. At present, Panspermia can neither be proved nor disproved. Nevertheless, Panspermia is an intellectual idea which holds strong attraction. However, at the heart of Panspermia is a still un-resolved mystery: in order to migrate, life has to start somewhere, and we still cannot tackle that moment of origin."
Source: Burchell, M.J. Panspermia Today International Journal of Astrobiology (2004), 3 : pp 73-80
In short, there is both evidence and support for the concept. Perhaps you have confused an interest in a subject - the origin of life - with substantive knowledge about it.
@Robbitybob1,your wild speculation fails on several levels, only two of which I address here.
The physical make up of Mercury, large core, small mantle, is currently best explained by a massive impact that stripped a large part of the mantle from the planet. Subsequently Mercury was subjected to extensive bombardment that may have continued after the end of the Late Heavy Bombardment period. These conditions would not have been suitable for the development of life, even if volatiles were present on the planet.
You have offered no evidence in support of your contention that the Earth was 27 times larger. Evidence for the temperatures present in the proto-planetary disk at various stages in its evolution are against the presence of volatiles in the proportion you propose for the primitive Earth. You have to demonstrate why this evidence is incorrect and I doubt you are able to do this.