kayshapero: (CalicoCat)
About 9:56 pm, there was a sound like either a very small earthquake or someone driving by, but the house didn't shake enough for the latter. So after a bit I checked the  USGS "Did You Feel It?" site to see if someone had reported one and they had*. Rated about 2.7 on the Richter Scale; won't be surprised if that goes down in a bit - it was teeny.  Tossed in my two bits (Noticed it.  Barely.) For the fun of it looked up the epicenter coordinates on Google Earth - less than 100 yards from here, down the short block and around the corner. Given a depth of 9 km, that effectively puts it right under us.  At this point Vicky called who understandably did NOT feel it being several miles away.  But apparently she had friends calling about "did you hear about the earthquake under your parents' house"... Shared amusement (both of us grew up in SoCal; microquakes are no big deal).  Anyway, may as well assure the World at Large that we are Just Fine and considering what to sell as souvineers.  :)

*2015-09-04 21:55:33 LOCAL if you want to look it up
kayshapero: (CalicoCat)
Well, that was interesting.  Started out reading my ecopy of The Science of Discworld, when a stray remark therein reminded me of the fossilized natural nuclear reactors someone found in the early '70s, and told me the name of the place was Oklo, Gabon in West Africa.  So, Google being handy, off I went to find this:

The Oklo Fossil Fission Reactors

oklo mine

Above: Oklo minesite 1997 [Photo by Minesite Engineer, Andreas Mittler].

This is one of the most fascinating stories in the relatively short history of Science and especially in the even shorter history of Nuclear Physics. In 1972 the very well preserved remains of several ancient natural nuclear reactors were discovered in the middle of the Oklo Uranium ore deposit. (more)

OK, after reading this article (go do likewise - they aren't kidding about the fascinating part), I was left wondering a) where on the planet was this location the billion years ago that the reactors were active, b) what life, if any, there might've been around at the time and c) if the author's eddress correctly implies that the Australians, like the British, refer to as a "thousand million" what the rest of us call a "billion".

More research.  1.2 billion years back a supercontinent dubbed "Rodinia" seems to have formed, with West Africa being the portion closest to the South Pole instead of the equator where you find it today. It came apart 350 or so million years later, bracketing the time I was looking for.  There wasn't any life on land to be discommoded, though there were multicellular lifeforms in the ocean.  Just a lot of rock deposits sitting there warming up their surroundings until the water baked off and the reaction stopped, then starting up again when they got more water.  Finally things changed too much and it stopped, leaving anything radioactive to decay peacefully, and proving that a billion years makes a heck of an effective radiation shield.  :)

Anybody got an answer to question c?

September 2018

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