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foone @Foone
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Watching the latest @DJSnM video and learned something interesting: We didn't discover that meteorite impacts leave shocked quartz behind until AFTER we discovered shocked quartz around nuclear detonations!
it's just amazing to me that most impact sites around the world are going to have shocked quartz and we didn't discover it at any of them. we only discovered it when we were examining artificially created shocked quartz.
and Eugene Shoemaker goes "hang on, shouldn't we see this around impact craters?" and the answer is yes, we should. and do.
Shocked Quartz is a neat form of quartz that happens when a powerful force causes the crystalline structure to deform along planes in the crystal, which look like lines when you examine them.
this lets you tell impact craters apart from volcanic craters because volcanic craters aren't strong enough to generate it, or they'd be too hot and melt the crystal, causing it to reform normally when it cools down
So you only get shocked quartz when something that's very powerful but doesn't involve a lot of heat.
In other words, things like meteorite impacts and nuclear detonations.
It reminds me of another nuclear-related discovery: gamma ray bursts.
These are intense explosions happening in distant galaxies, which are very rare and energetic. The theory is that they happen when big stars collapse into neutron stars or black holes, in a supernova.
They're very very bright, and are so strong that it's theorized if one of them went off in our galaxy that was aimed at us, it'd cause a mass extinction event.
Think about that: It's an explosion that could happen on the OTHER SIDE OF THE GALAXY and still kill us all.
These are happening all the time, but we didn't know about them until the 1960s, and didn't declassify that research until 1973.

Because we couldn't see them until we had gamma-ray detectors in orbit. The atmosphere absorbs most of the gamma rays.
Any guesses as to WHY we had gamma ray detectors in orbit?
Because we were worried the USSR would do secret nuclear tests, in violation of the Nuclear Test Ban Treaty of 1963.
Nuclear explosions produce a bunch of gamma rays, so we could use gamma-ray detecting satellites to find out if the soviets were doing secret tests.
But 4 years after the Vela series of satellites was launched, they detected some gamma rays. The signature was wrong to be a nuclear test, so it was ruled out as not important. probably just a problem with the detector or a solar flare or something...
But as they launched more satellites with better and more sensitive instruments, they kept seeing them. Eventually they had enough satellites that they could measure the time difference between when each satellite saw the gamma rays, and figure out the direction
and the direction wasn't from earth. So unless the soviets were secretly testing nuclear weapons out in the far reaches of the solar system, this was not nukes. this was something different.
So the scientists were able to get this finding declassified so the wider astrophysics community could study them, and we've launched a few satellites since then just to study them. They're still not fully understood, however.
and they're a very neat part of astrophysics we wouldn't have known anything about if the US hadn't been worried that the Soviets were doing secret nuclear tests.
two more fun facts: We still have gamma-ray detectors in space, pointed at the earth.
They just merged this functionality into some satellites we were already launching:
The Global Positioning System satellites!
in addition to the radio signal functions and accurate clocks that make GPS work, these satellites also contain gamma ray detectors and cameras, to let the US Air Force (who run GPS) detect nuclear explosions anywhere in the world.
The other fun fact:
The first gamma-ray bursts were written off as malfunctions or spurious cosmic events, but there's at least one time the detectors went off that hasn't been tracked back to a known above-ground nuclear test: The Vela Hotel Incident.
above-ground nuclear explosions emit a distinctive double-flash, that large conventional explosions or meteor impacts don't.
It has to do with how the explosion's shockwave travels through the atmosphere. There's detectors for this on most tanks and bunkers, and on satellites.
So once time when they went off and it wasn't directly confirmed to be a nuclear explosion was in 1979, off Prince Edward Islands of Antarctica. The official explanation was that it was some natural event like lightning or a meteor (possibly hitting the satellite!)
But there's also reasons to believe that it may have been a covert nuclear test, by either Israel, South Africa, or both working together. Both countries had worked together on nuclear weapons before, in secret.
if so, it was done very secretly: the only satellite that saw it was one that had been broken but restored to partial working order.
All the others were blocked by weather or aiming a different way, almost like someone timed the test to when it couldn't be seen...
Since the end of Apartheid there's been a lot of documentation on the South African nuclear program, however, and it suggests that South Africa was definitely not able to develop a nuclear weapon until a few months after the 1979 event was seen.
additionally, we know how much nuclear material they had, how many bombs they could have built with it, and all that material is now accounted for. And there's no 3-kiloton-warhead sized hole in the inventory.
Israel, on the other hand... has a much more secret nuclear weapon's program. In fact, even to this day, they are not actually confirmed to have any nuclear weapons. They maintain an intentional policy of ambiguity.
So while they officially neither deny or admit to having nuclear weapons... it's widely accepted that they do, since at least the 60s. So they definitely would have the ability to mount this test, especially with South Africa's help.
They're also a key ally of the US, which would give the US reason to not want to investigate too deeply into what exactly happened off Antarctica in 1979.
IN ANY CASE, go check out Scott Manley's latest video. It's not about south african nukes or even gamma ray bursts, but about an impact crater in greenland:

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