Bennu unboxing shows ancient asteroid holds carbon and water Initial analyses of samples collected from the surface of Bennu reveal the ancient asteroid contains water and carbon-based molecules, vital materials needed to create and support life. "As we peer into the ancient secrets preserved within the dust and rocks of asteroid Bennu, we are unlocking a time capsule that offers us …
If bacteria tootle around the galaxy on interstellar meteorites at approximately 1/10,000 of the speed of light, they could travel the galaxy's diameter of 100,000 light years in about 10**9 years. But bacteria might not survive for more than 10**6 years, so it would take many separate steps for bacteria to span the galaxy.
Other galaxies, even Andromeda, are too far away for their bacteria to have reached us.
'The panspermia hypothesis is just throwing the problem over the wall.'
Well not really, as amino acids have been discovered in meteorites subsequent to their experiment it really provides an alternative hypothesis which these missions are attempting to ratify.
If you accept Miller and Urey's experiment and hypothesis as being a source of Earth's amino acids then there is no reason why it can't have happened elsewhere ( in multiple places ) given the appropriate conditions.
Miller and Urey's hypothesis was formulated against a backdrop of the Solar System being the only known planetary system.
This is no longer the case.
There is still only one planet demonstrated to have life on it. The fact that this is extended to anything between "must be others" and "must be ubiquitous where ever conditions are right" is extreme observe bias.
Looked at objectively the number of systems which have to come into existence, come together and become integrated into a working whole makes the existence of life extremely unlikely. Once it exists it's extremely good at propagating the unlikely which is maybe why it seems inevitable.
Agreed, however their experiment only showed that amino acids could be formed in conditions 'believed' to be in place during the early Earth and unfortunately that hypothesis is untestable ( without a time machine!).
The accepted fact that there are actually multiple planets and systems out there now means there are many 'chemistry sets' out there capable of generating these building blocks given the right conditions.
If accepted wisdom says that water and other compounds were brought to Earth via comets and meteorites then why not the basics of organic chemistry?
That is testable.
Water, carbon... if they're the key ingredients for life. But let's not get ahead of ourselves. The real miracle isn't life. It's the Funk music. I mean, seriously, can a splash of water and a sprinkle of carbon bring forth the groovy tunes of Bootsy Collins? Now THAT would be out of this world!
We know there are plenty of simple organic molecules kicking around the galaxy, and they would have been there on early Earth. But we do not yet know how they became the intricate and precise molecules of proteins, RNA, DNA, or cellulose.
I am tired of these headlines about 'the key to life' when we are as far from ever from explaining the origins of RNA etc.
I applaud the technical genius that has brought this sample back to earth, but there is an issue that I don't recall having seen addressed anywhere, which is, How representative is the sample of the bulk of Bennu? Bennu's surface is subject to a variety of erosional effects, such as outgassing of volatile elements, gardening by micrometeorites, and erosion by the solar wind. Surely this must mean that the surface down to an unknown depth is a sort of remanié (otherwise known as lag) deposit? So the surface layers might well be enriched in less volatile and more durable substances and depleted in fragile or volatile materials. I am sure the PIs will have considered this, but I haven't actually seen anything in a public statement.
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