
Oldest Material on Earth Discovered - Hooke
https://www.bbc.com/news/science-environment-51099609
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leeoniya
> "I compare this with putting out a bucket in a rainstorm. Assuming the
> rainfall is constant, the amount of water that accumulates in the bucket
> tells you how long it was exposed," said Dr Heck.

does this imply that cosmic rays have been constant for half the age of the
universe? or at least have a predictable decay rate? or is this just a weak
analogy?

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cobbzilla
I wondered this as well.

Also, even if the rate of cosmic rays has been constant, would it make sense
that the impact of said rays on any body would be perfectly uniform? Wouldn't
it follow a normal/gaussian distribution, such that some parts of the
meteorite received a bit more cosmic rays, and some a bit less? Do the "ages"
they found follow such a distribution?

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sandworm101
>> such that some parts of the meteorite received a bit more cosmic rays, and
some a bit less?

Everything in space spins, from the smallest speck of dust to entire galaxies.
Put a stationary object in space, in light, and that light will start it
spinning. So we would expect cosmic rays to be uniform across the surface.

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BurningFrog
True, though they spin around one fixed axis.

So if there is a big radiation source due "north", there should be less
radiation received on the "south" side.

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yborg
What I found to be the most interesting observation is that the majority of
the grains found have an age very close to the assumed age of the Sun itself.
This kind of implies that the the cloud that the Solar System formed from was
mostly seeded by the event that began cloud collapse.

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drallison
How do they know that the material they discovered is the "oldest material on
earth"?

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ur-whale
Not a hint of the chemical composition in the article, or did I miss it?

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Ericson2314
How much neon is there? If there is too much new element formation I'm not
sure what the chemical composition would mean.

