
Fun? Challenge accepted.
Maybe if it crashed into the earth it'd wipe out the life here that's made such an utter fuck up of the planet and seed new life that gets it right?
Scientists analyzing samples from asteroid Bennu have found something remarkable: Despite being a cold, lifeless rubble pile that formed around 65 million years ago, it holds a rich inventory of organic molecules - key ingredients for life. Returned to Earth by the OSIRIS-REx spacecraft in late 2023 - and sealed inside its …
This is completely uninformed speculation but given that Bennu is 65 million years ago I got to wonder whether it might be composed of ejecta from the Chicxulub impact some also 65 million years ago.
Unlikely, I suppose, but it would explain the biological signatures that, as far as I'm aware, haven't yet been found elsewhere.
Can someone with a bit of domain knowledge help me out here? "No way" is a perfectly acceptable answer.
I'll bite, no way.
The chemicals analysed from Bennu were racemic. If they had originated from Earth, either ejecta or contamination of these experiments, then the enantiomers would be unbalanced. Most of the essential amino acids of (Earth) life are laevorotatory.
I'm not seeking to bamboozle, rather leaving it to the reader to follow up on the technical terms. Chirality is important and simple in some respects but often overlooked.
"Maybe if it crashed into the earth it'd wipe out the life here that's made such an utter fuck up of the planet and seed new life that gets it right?"
Ehm... No. An impact potent enough to "wipe out life" on earth (from your phrasing I must conclude that you mean the entire planet will be sterilized) would not only have be so kinetically energetic that it could break the Earth apart, but it would also liberate so much heat that any organic matter contained in the foreign body would be completely destroyed.
"all five nucleobases that form DNA and RNA"
Good to see that being reported. I read a report in another place that ignored uracil which is arguably more important than thiamine. It's RNA which is at the business end of protein synthesis with DNA coming late to the party.
"one of the mysteries of the Bennu samples lies in the chirality of the amino acids they contain. Terrestrial life relies almost entirely on left-handed amino acids, but those found in Bennu exhibit no such bias"
I'd have thought it was entirely to be expected.
Given "that Bennu contains 14 of the 20 amino acids essential for life on Earth"...
And Assuming that Bennu is a typical example...
Does this mean that there is at least a 70% chance that lifeforms on Goldilocks Zone Exoplanets will have a similar biology to here on Earth?
If so it means we are not alone :)
Unfortunately, given our current tech, we will not be able to find out for millions, or billions, of our years
We can't be. The Hubble Deep Fields experiment proves that, whatever point in the sky you look at, there's a galaxy somewhere out there.
A galaxy. Millions upon millions of star systems. And we now know that most stars have planets.
There is life out there. It's just that there is a vanishingly small chance that we ever communicate with it, let alone meet it.
We may not have to wait that long if there are lifeforms that are sufficiently advanced to generate the detectably organized EM signals that SETI has been looking for for decades.
That they haven't yet found any suggests that either there are no such advanced lifeforms within 50 lightyears or so, or they're using frequencies that we can't or don't detect.
It would appear that you will get nucleotides and amino acids forming in quite challenging environments with possibly a smidgen of water as a prerequisite. These conditions must exist over most of the Universe and unless the step from these precursors to even the most primatitive life forms is impossibly unlikely it would follow that the Universe is teeming with life even if we restricted ourselves to life based on nucleic and amino acids.
If we find evidence of life on Mars either now or in the distant past I think we might have some confidence that the emergence of life is not impossibly unlikely.
I find this thought an ember of optimism in these pessimistic times.