Dust cloud sparked explosion in primitive life on Earth, say scientists

https://www.theguardian.com/science/2019/sep/18/dust-cloud-sparked-explosion-in-primitive-life-on-earth-say-scientists

by jajag • 7 years ago

53 12 7 years ago

baq2• 7 years ago

the path from the beginning of time to being able to understand it is nothing short of amazing. the amount of things that happened to allow homo sapiens to evolve is staggering.

does anybody keep an up-to-date list of drake equation coefficients?

ozim• 7 years ago

yes: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis

jcims3• 7 years ago

I know this isn't the right way to think of it but it does attest somewhat to the rarity.

If every atom of the universe (1e82) was a specialized computer that was able to create a trillion universally unique combinations of a 200 base pair strand of DNA per second (1e12/second) , and you had them all working on this task from the beginning of known time (4.4e17 seconds), you would have discovered approximately .0000002% of the possible combinations (4.4e111/4^200).

It's a little difficult to get a straightforward answer but the simplest organism I'm finding right now has 160,000 base pairs in their DNA.

paulryanrogers• 7 years ago

If the number of atoms in the universe, including those unknown, is infinite then even small probabilities can approach certainty.

java-man• 7 years ago

The simplest molecule (dimer, actually) that has self-replication and evolution has a complexity of about 170 nucleic acid bases [0]

It is entirely probable, in my opinion, that this is how life originated on Earth in a shallow pool or volcanic vent - essentially primordial PCR machines.

[0] https://www.pnas.org/content/99/20/12733.short

hyperpallium• 7 years ago

But once life gets started, it's easier to see how useful complexity can grow through evolutionary pressure.

You've pr. seen this bactrapolation of exponential growth in complexity of life: https://www.technologyreview.com/s/513781/moores-law-and-the...

Why don't we see the predicted simpler forms of life? They might not cope with the changed environment (e.g. oxygenation event), not be competitive with subsequent life, or we don't recognize them as "life" (e.g. viruses), or we just haven't detected them yet.

"RNA world" is one theory, of a previous form of life that used only RNA, and no DNA. It's suggestive thst some of the most basic and ancient cellular mechanisms (transcription) are based on RNA. [I'm not an wxpert]

There may have also been a "<predecessor> world" before that.

And the dating of the earth's formation suggests all this may have been on a different physical world too.

mrlala• 7 years ago

the amount of things that happened to allow homo sapiens to evolve is staggering

Yes.. but.. one perspective is it's only so staggering if we look at it in the frame of "Look at all the things that had to happen in order for us to specifically develop"

If you remove what we consider "us" from this equation, I'm not sure it's all that staggering. Well, it is of course, but maybe not really. With the absolute insane amount of time that has passed and all the matter everywhere interactive, there is so much going on that I'm not sure it's much of a wonder that something happened.

By something, I suppose I mean the very beginnings of what we call life. And where it goes from there is just an absolutely infinite number of possibilities. But we somehow look at just ourselves and think "wow look at all the stuff that had to happen to make me" but there are an infinite number of ways that "me" could have been.

I'm not sure I'm explaining it all that well... I suppose my point is over so much time it's not so surprising that something happened. We are just one possibility in billions, so there are so many ways the entire of our planet could have played out.. or not at all. And it's the same all throughout the universe.

Speaking of which, does anyone have any articles or books on what other similarly intelligent life could actually be like? I try to think, what if we were intelligent sea creatures. Would we have been able to do as much being mostly confined to water.. would we have been able to come up with basic technologies to get out of the water and harvest resources, or maybe we would have just found ways to mainly use resources found in water. But could we have developed enough technology? What if we were shaped completely differently, is there something about our form that has been efficiently evolved over time, or are there countless other sizes/shapes that would have allowed us to be at the state we are now.

I've really always thought that any intelligent life on other planets would probably be so ridiculously foreign it would probably scare the shit out of us. There's no reason to think they have the same "emotions". That's just an evolutionary trait to our planet. Would they have humor? The same sense of happiness and sadness? I don't see why a brain would naturally evolve in a similar way given a completely different set of evolution, although I have no knowledge in this area.

Well thanks for the existential crisis.

baq2• 7 years ago

seems like you need to read some good scifi. i'd recommend the culture series.

marmadukester39• 7 years ago

Wonder if any of that sparked biodiversity was due to panspermia

sword_smith• 7 years ago

I thought this would be about the Cambrian Explosion but that is 541m years ago, and this alleged asteroid blew up 466m years ago according to the article. Both periods, The Cambrian Explosion and the Great Ordovician Biodiversification Event (GOBE) are periods with strong biological radiation as can be seen on the 1st graph here: https://www.fossilhunters.xyz/fossil-classification/images/1...

The Cambrian Explosion is replaced by the 'Cambrian Plateau' (not a canonical name), and the GOBE comes after. The Ordovician animals were the first to evolve jaws (in Gnathostomata/jawed vertebrates). This happened about 462m years ago, so perhaps we can thank a 93 mile asteroid that blew up 466m years ago for our ability to chew?

They found a pretty interesting dataset, it seems, relating various isotopes. It's a pitty the article don't go into details on the chemical signature that convinced the scientists that leftovers of an asteroid rained down on Earth.

Dust cloud sparked explosion in primitive life on Earth, say scientists

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