4.6B-year-old meteorite found
lboro.ac.uk
lboro.ac.uk
In that case, it's not exactly remarkable - I think pretty much all the asteroids in the Solar System are 4.6B years old, because that's when they were all created.
https://en.m.wikipedia.org/wiki/Oldest_dated_rocks
It is unusual, though, you're right.
The ocean floor is virtually completely newer material, little of it over a 200 million years old (about 5% of Earth's total age), due to subduction. Continental crust is lighter, floats on top of the heavier oceanic crust, and has at least a chance of survival.
https://www.thoughtco.com/how-old-is-the-ocean-floor-3960755
https://en.wikipedia.org/wiki/Canadian_Shield
https://en.wikipedia.org/wiki/Jack_Hills
https://www.geologyin.com/2015/11/44-billion-year-old-zircon...
https://www.geologyin.com/2016/03/the-oldest-mountain-on-ear...
https://www.thoughtco.com/how-old-is-the-ocean-floor-3960755
It doesn’t appear to have undergone thermal metamorphism, which means it’s been sitting out there, past Mars, untouched, since before any of the planets were created meaning we have the rare opportunity to examine a piece of our primordial past."
Basically, if the wording is correct, that's unusual even for meteorites.
“It’s a scientific fairy-tale. First your friend tracks a meteorite, then finds it and then gifts a bit of this extra-terrestrial material to you to analyse."
The age of the Earth is accepted as 4.54 +/- 0.05 billion years (determined to within 1%, that is, within 50 million years). That's based on samples of the oldest available Earth rocks, as well as lunar material (much returned by the Apollo missions), and other meteorite finds (Antarctica turns out to be highly effective at revealing meteorites as virtually all recent terrestrial rock is several kilometers under ice).
But the article does indicate that the age and primordial nature of the specimin is the principle interest:
“It doesn’t appear to have undergone thermal metamorphism, which means it’s been sitting out there, past Mars, untouched, since before any of the planets were created meaning we have the rare opportunity to examine a piece of our primordial past.
The one detail the article fails to provide is how the specimin was dated, though at 4.6 billion years, it's about 100 million years older than the highest accepted age of Earth itself. It would represent material from before the era of planetary formation within the early dust cloud from which our Solar System was formed.
It sounds like that's par for the course for this type of meteorite. So it's rare, but not unique: https://en.wikipedia.org/wiki/Carbonaceous_chondrite.
> The carbonaceous chondrites were not exposed to higher temperatures, so that they are hardly changed by thermal processes. Some carbonaceous chondrites, such as the Allende meteorite, contain calcium-aluminum-rich inclusions (CAIs). These are compounds that emerged early from the primeval solar nebula, condensed out and represent the oldest minerals formed in the solar system .[3][4]
> Some primitive carbonaceous chondrites, such as the CM chondrite Murchison, contain presolar minerals...
It's not clear to me that this is the oldest meteorite found, how it was dated, how it was tracked, etc., etc.
For the technical deets on dating CCs:
What evidence is there that it is not?
Looking out in space is looking back in time. Numerous phenomena support very strong consistency of physical constants to all observable levels. lizknope mentioned on HN recently naturally-occurring fission reactions on Earth about a billion years old or so. Those provide direct physical validation of physical constants as well.
https://news.ycombinator.com/item?id=27753154
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
A phenomenon which can arbitrarily change basic perceptions leaving no trace is definitionally beyond the capabilities of an empirical observation to detect. The notion itself is solipsystic and borders on meaninglessness.
The same way as the Earth appears largely flat to the observer standing on it, but from space it is clearly an oblate spheroid.
Science isn't just asking "what if...?" It's following up with "... and how could I demonstrate that?" The third step is then "how do I communicate that to others?"
In the domain of chemistry, there's a wonderful example of that in Michael Faraday's "The Chemical History of a Candle". YouTube's EngineerGuy (Bill Hammack) has a wonderful recreation of Faraday's public demonstration of these properties. It seems obvious and pedestrian now, but that's because Faraday introduced us to these concepts and convinced us, collectively, of their fundamental truth. He gives us the hypothesis, he gives us the observable consequence, and he then demonstrates that consequence. Six-part series starting here:
https://youtube.com/watch?v=RrHnLXMTOWM
I've already answered your question, as it happens:
Looking out in space is looking back in time. Numerous phenomena support very strong consistency of physical constants to all observable levels. lizknope mentioned on HN recently naturally-occurring fission reactions on Earth about a billion years old or so. Those provide direct physical validation of physical constants as well.
That is, we have zoomed out time, using telescopes, looking back in the Universe 13.772 billion years (9.2 billion older than the Earth's own age). And there's no observable change in any of the fundamental physical constants that we can detect over this range.
But since you've repeated the question twice: why do you ask?
Ref. https://www.youtube.com/watch?v=uYNzqgU7na4 for entertaining additions.
New to Herzog? Most of the user reviews on IMDb are complaining it's not the usual impersonal science program they'd evidently expected, so please don't make that mistake. There are a few segments about meteorites in myths/religions. Herzog's documentaries all kind of feel like anthropology, no matter the topic. He's fascinated in people, and celebrates us in all our weirdness. e.g. His 2016 documentary about the internet, Lo and Behold: Reveries of the Connected World[1], was one of the best things on the subject I'd seen.
Found in imprint of a horseshoe? What? Tracking it before it landed?
Like in desert areas people will metal detect for meteors, but how did they find this one.
https://ares.jsc.nasa.gov/meteorite-falls/how-to-find-meteor...
Landed on the Earth 4.6B years ago? That doesn't sound right, the Earth isn't that old.
Flew off its former body 4.6B years ago? How do we measure that?
Created 4.6B years ago? How does one define created, considering everything was ultimately created during the big bang?
It contains organic material, which means the dust that formed our solar system, contained plenty of it.
If it arrived yesterday in earth, it still is 4.6b old.
"Identifying organic compounds would support the idea that early meteorites carried amino acids – the building blocks of life – to supply the Earth’s primordial soup where life first began.
“Carbonaceous chondrites contain organic compounds including amino acids, which are found in all living things,” said Director of Astrochemistry at EAARO Derek Robson who found the meteorite and who will soon join Loughborough University as an academic visitor for collaborative research.
“Being able to identify and confirm the presence of such compounds from a material that existed before the Earth was born would be an important step towards understanding how life began.”"
It's way too small to clump from its own gravity, it pretty much has to be a portion of something MUCH larger.
Keep in mind that "gravitational accretion" simply kicks the can a bit further: the chunks that accrete gravitationally must themselves form and congeal somehow.
What I understand of solar system formation is that all "metallic" solar systems (though with a substantial portion of elements other than hydrogen) from from the remains of earlier stars. So you have a nova, supernova, stellar collapse, collision (stars, white dwarves, neutron stars, ...). This ejects heavy materials (principally H, He, C, O, N, though others --- water is probably the most common non-elemental molecule in the Universe), and also creates pressure waves and imparts angular momentum. Both factors can draw material together. There's also probably a lot of plasma in the mix, so that different portions of the cloud carry different charges. These may be attracted, repelled, and spark discharges (which might themselves melt and fuse material). There may also be surface-tension effects and other factors at play. Somehow, clumps form. Gravity is a force at work, but not the only force.
Disclaimer: not an astronomer, just interested in far too many divers subjects. If anyone has anything authoritative to say on this I'm all ears. Most references I can find are either extremely basic, or address the formation of asteroid belts but not the objects within them.
There's some hypothesis on formation (condensation, shock waves, jet flows) here: http://www.psrd.hawaii.edu/Sept02/isotopicAges.html
The age of formation of rock is typically determined unequivocably by radiometric dating. That "clock" uses the ratios of long-lived radioactive elements and their decay products (this is not radio carbon dating, which is similar but effective over a much shorter timespan of about 50,000 years).
The radiometric clock starts when the materials in the sample solidify and initial proportions of mother and daughter elements are fixed, "neither the parent nuclide nor the daughter product can enter or leave the material after its formation" (Wikipedia). That point in time is the "age" of the rock.
The specific decay chains used in geology are uranium–lead, samarium–neodymium, potassium–argon, rubidium–strontium, and uranium–thorium. These may rely on crystaline structures which cannot form when the daughter elements (decay products) are present, therefor the amount of daughter element present gives the age. (I know this is the case for some methods, I'm unsure it applies to all. The "this structure cannot form when the daughter products are present" feature is a compelling argument for age.)
https://en.wikipedia.org/wiki/Radiometric_dating
Newly-formed lava or other molten materials are "new" --- they've just been created as rock. The elements within them are older --- those date to whatever radiological apocalypse formed them (stellar fusion for elements up to iron, various novae and collisions between white dwarves and neutron stars for elements heavier than iron). And of course the protons and neutrons comprising them ... mostly ... date to the origin of the Universe in the Big Bang (there is some spontaneous creation of particles due to quantum energy and mass-energy fluctuations, though that's minimal).
The atomic transmutation of elements gives some interesting results. Virtually all of the helium in the Universe formed in stars from fusion of hydrogen. A very small percentage was formed in the Big Bang. But virtually all helium on Earth is the result of radioactive decay of heavy elements, forming beta particles (two protons and two neutrons), that is, a helium nucleus. When that picks up electrons, it becomes helium. It's generally trapped with natural gas and produced as a by-product of gas wells.