[extropy-chat] Re: Animals
eugen at leitl.org
Wed Feb 18 17:15:57 UTC 2004
On Wed, Feb 18, 2004 at 03:38:15PM +0000, Christian Weisgerber wrote:
> > Mid-Life Crisis for the Earth
> > 5.6 Gyr (1.1 Gyr from today):
> > * Sun 10% brighter: ~1.1 Lsun
> > * Cause a moist greenhouse effect on Earth, driving away most of the
> > * water in the air.
> Oh, okay. That is of course a long shot from the previously claim
> that "the sun's expansion would destroy life on Earth in 500 million
Not really. Half a gigayear is ballpark figure. And of course this ignores
giant impacts, which will produce major extinction events and radical loss of
biodiversity (if not even higher life). You need a lot of time to rebound
from that. Arguably, more time that this biosphere's expiration date.
> > I have no idea how reliable is this. Even 1% of solar constant change
> > typically can wreak havoc to climate, so 10% increase sounds pretty
> > catastrophic to me.
> Yes, but it's a slow, continuous process. Anybody have any figures
No, luminosity quite suddenly starts going up once you go off the main sequence on
Hertzsprung-Russell. It's basically constant while you're still in hydrogen
burn. I was looking for a luminance curve vs. age for a
Sol-mass star, but haven't found any on the fly.
Since I'm at work, the best I can do is
> how much hotter the sun has grown over the time we've had multicellular
> life on earth?
-- Eugen* Leitl <a href="http://leitl.org">leitl</a>
ICBM: 48.07078, 11.61144 http://www.leitl.org
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