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View Full Version : Could the Sun generate flares strong enough to sterilize Earth?



cjackson
2015-Dec-12, 09:06 AM
I read in one of Phil Plait's books about disaster scenarios involving ultra solar flares sterilizing the planet. Could such a thing happen?

StupendousMan
2015-Dec-12, 01:40 PM
Well, it hasn't occurred for at least the last 400 million years or so; fossils show that animals and plants have been living on the land for that long.

What little I know about solar flares and stellar evolution suggests that they aren't likely to change their behavior radically in the near future.

Spacedude
2015-Dec-12, 02:24 PM
Another CME like the one that occured in 1859 might sterilize our electrical grids pretty good.

Ken G
2015-Dec-12, 02:31 PM
Note that the Earth's atmosphere and magnetic fields provide substantial protection from gamma rays, X rays, and energetic particles. So the scale of the required energy seems pretty far beyond the pale of anything we have reason to worry about. Our orbiting satellites, or astronauts exposed in space, would be another story!

Jens
2015-Dec-12, 02:36 PM
Another CME like the one that occured in 1859 might sterilize our electrical grids pretty good.

Yes, our grids may be at risk. Life on earth, not so much.

Spacedude
2015-Dec-12, 02:43 PM
Yes, "life" not so much, our way of life though would be signing off here and pretty much in panic mode world wide.

slang
2015-Dec-12, 04:51 PM
Yes, our grids may be at risk. Life on earth, not so much.

Mmm.. hot grits.

Noclevername
2015-Dec-12, 05:15 PM
And even sterilizing land life doesn't mean all life on Earth; underground and deep ocean organisms will be able to withstand any surface radiation short of melting the Earth's crust.

Fiery Phoenix
2015-Dec-12, 05:57 PM
The main issue is not necessarily life itself, but the effect such phenomena would have on our satellites. A powerful solar wind could cause orbiting satellites to malfunction (either temporarily or permanently), which in turn would translate into problems for us down on Earth.

01101001
2015-Dec-12, 07:25 PM
Recently in the news: Sun Could Unleash Devastating 'Superflare' (http://news.discovery.com/space/sun-could-unleash-devastating-superflare-151208.htm)

So the consequences of a superflare (and possible associated super-CME) could be disastrous, [Chloe] Pugh said.
But you shouldn't worry too much about this worst-case scenario, she added.

Ken G
2015-Dec-13, 11:13 PM
Yes, among other things, the "superflare" they were studying occurred in a binary star system. Such systems are notorious for large flares, because the binary orbit stores a large amount of angular momentum that can be drawn on to keep the stars spinning fast. Fast spin really helps stir up the magnetic activity needed for big flares. I don't know that binary system, but it kind of sounds like that is what is going on there. The Sun, on the other hand, has a lazy spin period only about one rotation per month, so its flares are pretty wimpy.

Jens
2015-Dec-14, 01:43 AM
And even sterilizing land life doesn't mean all life on Earth; underground and deep ocean organisms will be able to withstand any surface radiation short of melting the Earth's crust.

In addition, I think that solar flares usually don't last so long, an hour at the most (though I'm not sure about what would happen in a super flare), so that people on the side of the earth not exposed to it would also be fine.