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Ryugu asteroid samples contain all DNA and RNA building blocks

phys.org

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Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#51

Post by kmaitreys »

8bitsrule wrote: post #45
0x000xca0xfe wrote: post #8

One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago. I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison? The missing part is how do they form se…

The major flaw in Panspermia is that it all had to start somewhere without Panspermia. If it did that there, why not here?

It had to start somewhere which is favourable to preserve the necessary molecules. Early Earth was not such place.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#52

Post by kmaitreys »

qsera wrote: post #38

Doesn't multi-world interpretation pretty much answer how life originated? I mean, even if the starting state require to bootstrap life have impossibly low chance to happen random, multi-world interpretation implies that there will be some worlds where it happened, and observation of life is only possible in such worlds..

Multi-worlds is not really relevant here. You are just asking the question how the building blocks of life form in the Universe and how can they reach a planet like ours.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#53

Post by michaelsbradley »

8bitsrule wrote: post #45
0x000xca0xfe wrote: post #8

One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago. I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison? The missing part is how do they form se…

The major flaw in Panspermia is that it all had to start somewhere without Panspermia. If it did that there, why not here?

One way to think about that is time required:

If earth is about 4 billion years old, but it takes say 400 trillion years for natural processes to produce this chemistry, then it happened out there not here.

This was a key reason why Hoyle preferred a steady state model of the universe — the part of the universe we inhabit needs to be very, very old for this stuff to work out, according to his thinking. A minority opinion, for sure, his rejection of the Big Bang model and timelines lost him a lot of respect among his peers. And his ideas could be wrong, I’m just pointing out that historically panspermia proponents have taken this position as to “why not here”.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#54

Post by Symmetry »

drob518 wrote: post #44
stouset wrote: post #41

Earlier quoted context omitted.

Only the outer surface of asteroids gets hot. Atmospheric entry isn’t long enough to thoroughly cook a rock.

What about the immense energy that is released when it slams into the earth at supersonic speeds?

A asteroid has to be absolutely huge to make it all the way down to the surface without slowing down to terminal velocity. Your typical 1kg asteroid will have slowed to terminal velocity dozens of km above the surface. The smaller an object the lower the ratio of its mass to surface area and the more easily it slows down.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#55

Post by HarHarVeryFunny »

0x000xca0xfe wrote: post #8

One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago. I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison? The missing part is how do they form se…

> Wouldn't a couple asteroids be the literal drop in the ocean in comparison?

Actually most water on earth probably came from asteroids, so they are the entire ocean! They would also have brought a lot of frozen methane and ammonia, so most of the chemicals necessary for terrestial life.

When the solar system was forming, the protoplanetary ring of cosmic dust would have consisted of heavy elements (some essential for life, such as phosphorus) closer to the sun and frozen lighter elements further away. The heavy elements would have combined into the early rocky earth, and as the other planets formed and orbits stabilized the icy asteroids from further out would have been flung around and impacted the planets.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#56

Post by freedomben »

make3 wrote: post #35
0x000xca0xfe wrote: post #15

Earlier quoted context omitted.

We could artificially create a sterile, large pool of the ingredients and see what happens. I've read about experiments like this but only at lab beaker scale.

It's funny talking about non software stuff on HN. I'm sure there's hundreds of papers on simulations and expert analysis of this.

Surely in a minority, but I do see posts from people on HN that are scientists, researchers, even mechanics and such. We definitely get a lot of speculation, but I've learned never to underestimate the level of expertise of people in our community.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#57

Post by dan_hawkins »

0x000xca0xfe wrote: post #8

One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago. I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison? The missing part is how do they form se…

My layman guess would be that shortly after formation Earth was just a ball of lava that destroyed every organic component so when the surface solidified it was sterile.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#58

Post by adrian_b »

BinaryAsteroid wrote: post #40
lazide wrote: post #37

Earlier quoted context omitted.

Huh? Those smaller rocks would be even more irradiated, as they have no atmosphere? They’d also have to contend with re-entry.

The smaller rocks are composed of those materials in solid state (e.g., ice not water). They are less irradiated as they are further away from the Sun (think the asteroid belt and beyond). Atmospheric entry (if that's what you mean) is irrelevant. What matters here is the transport of materials from a place where they could have formed, to a place where they couldn't.

Atmospheric entry is completely relevant because some people have made the illogical claim that meteorites falling on Earth could have contributed with such complex organic substances, like the nucleobases, to the appearance of life on Earth.

The icy bodies from the outer Solar System that contain such organic substances are very easily vaporized during entry in the atmosphere of the Earth, so only a negligible fraction, if any, of the organic substances originally present in such a body would reach the surface of the Earth.

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#59

Post by [deleted] »

johnsmalles wrote: post #27

Fascinating that all five nucleobases were found in Ryugu samples. The fact that these formed abiotically in an asteroid environment strengthens the case that the building blocks of life are common throughout the solar system. The amino acid findings from the same samples were already compelling, but having the complete nucleobase set is a different level of evidence.

[deleted]

Re: Ryugu asteroid samples contain all DNA and RNA building blocks

#60

Post by lazide »

BinaryAsteroid wrote: post #40
lazide wrote: post #37

Earlier quoted context omitted.

Huh? Those smaller rocks would be even more irradiated, as they have no atmosphere? They’d also have to contend with re-entry.

The smaller rocks are composed of those materials in solid state (e.g., ice not water). They are less irradiated as they are further away from the Sun (think the asteroid belt and beyond). Atmospheric entry (if that's what you mean) is irrelevant. What matters here is the transport of materials from a place where they could have formed, to a place where they couldn't.

The earths poles?
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