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kengrA little something that came to me the other day...
The chunk of nickel-iron spun slowly in the vacuum. As such things go there wasn't anything special about it.
It was around one hundred meters along various axes. Likely broken off some larger body far in the past.
Wherever it had originated, it was approaching an encounter with another body. Earth, the inhabitants called it.
It wasn't large enough nor moving fast enough to be a "dinosaur killer". It was going to impact at around 30 km/sec. The blast would only be ten megatons or so. Not anything of more than local importance.
Alas, due to the impact point, it was going to be a lot more than a "local" disaster.
Unfortunately for humanity, it struck almost directly above the center of the magma chamber under the Yellowstone caldera.
Not only did it blast through the cap rock, it fractured most of it. so all the pressure that had been building for thousands of years released at once. and the trapped gases in the magma turned it to ash as the massive blast the mere 10 megaton one had triggered broke the pieces of the overlying rock into smaller and smaller pieces.
They'd still be quire large enough to cause lots of damage when they came down..
So would the blast effects.
But the ash, and later steam as various rivers tried to flow back into the immense crater where the magma chamber had been were what caused the lasting damage.
Global warming wasn't going to be a concern for quite some time...
The chunk of nickel-iron spun slowly in the vacuum. As such things go there wasn't anything special about it.
It was around one hundred meters along various axes. Likely broken off some larger body far in the past.
Wherever it had originated, it was approaching an encounter with another body. Earth, the inhabitants called it.
It wasn't large enough nor moving fast enough to be a "dinosaur killer". It was going to impact at around 30 km/sec. The blast would only be ten megatons or so. Not anything of more than local importance.
Alas, due to the impact point, it was going to be a lot more than a "local" disaster.
Unfortunately for humanity, it struck almost directly above the center of the magma chamber under the Yellowstone caldera.
Not only did it blast through the cap rock, it fractured most of it. so all the pressure that had been building for thousands of years released at once. and the trapped gases in the magma turned it to ash as the massive blast the mere 10 megaton one had triggered broke the pieces of the overlying rock into smaller and smaller pieces.
They'd still be quire large enough to cause lots of damage when they came down..
So would the blast effects.
But the ash, and later steam as various rivers tried to flow back into the immense crater where the magma chamber had been were what caused the lasting damage.
Global warming wasn't going to be a concern for quite some time...
no subject
Date: 2018-11-25 03:19 pm (UTC)Keep in mind that we are technically in an interglacial period, and the ice will return any millenium now. :-)
no subject
Date: 2018-11-25 08:42 pm (UTC)But the Yellowstone Impact would flip that quick.
The way I envision the eruption going, the ashfall on the Us would be somewhat lessened, but at the cost of more ash into the upper atmosphere where it could circle the globe.
so more or less "nuclear winter" type effects, without the radiation. There'd be more than just A "year without a summer" (cf 1815).
Not a good time for humans or anything else that depends on sunlight. (The deep ocean vent" ecosystems wouldn't even notice.)
Still better than one disaster that was discussed on rec.arts.sf.science many years back.
The idea was sparked by the bit in "Have space Suit, Will Travel" where the Three Galaxies were deciding whether or not to "rotate" Earth.
That is, displace it thru the 4th dimension to some other space-time. As noted, it would be *just* the planet, not the Sun or moon.
Great fun figuring out how fast things would freeze and what could be done to get a viable population to survive.
no subject
Date: 2018-11-26 01:52 pm (UTC)I used to work with trendline analysis for a living, so I have a better handle on overlapping trends than most folks.
When talking about natural climate trends, the short term is that we're (slowly) coming out of a record low sunspot cycle. The lower solar output cooled the globe by one or two kelvins (ie degrees centigrade for those who don't already know).
The medium trend is that we're in the rising part of the 750 year climate cycle. (Which is probably the average of several natural cycles.) The trough was right around 1800. Remember all those stories and artwork showing how bad the Winters were during the American Revolution? This, plus a major volcanic eruption, probably also triggered the French Revolution. The effect is slow and irregular enough that there's considerable argument about when the last minimum and the preceding maximum were, but the consensus is that we're now in the rise.
The long term is that the climate should turn seriously cooler in another two or three thousand years, starting perhaps as soon as a thousand years from now.
In the *really* long term trend, the Sun will bloat into a red giant and swallow the Earth. :-)