It's The End of the World as We Know It

[Aran]

(And I feel fine.)

 

So to you guys living west of the Atlantic (and thus pre-18:00) I just wanted to drop a note that we're still alive and unraptured over here, so the apocalypse appears to be subject to some technical delays. (I wonder how Camping will take it this time.)

 

I found one of the most awesome list-type Wikipedia articles in the process of reading about this (I have too much time, apparently). The last decade when the world wasn't scheduled to end were the 1820s. The last decade with only a single scheduled apocalypse were the 1950s. The last item on the page is particularly great.

[Student of Trinity]

Unraptured? Ah, too bad for you, Aran. I'm typing this from 60,000 feet, and climbing.

 

Naturally my iPhone got raptured with me.

 

Funny thing, though. My iPhone ... it's as if it's pulling upward. In fact, it's getting hard to type. My fingers are slipping off it ...

 

Aaaaaaaaaahhhhhh!

[Randomizer]

Well you had great reception.

 

I've survived another scheduled Rapture. There are somethings I don't mind being left behind.

[Aran]

I guess this isn't the year when they finally immanentized the Eschaton after all. Hail Eris!

[Callie]

I always hate it when the world ends on a Friday!

[Goldengirl]

Oh, fancy that. I didn't even know that we were all scheduled to die today. It would have motivated me to finish watching The Matrix instead of cutting it off to go to class. Alas.

[Ceiling Durkheim]

Remains imminent, rather than immanent.

[Triumph]

That list on Wikipedia left out Chronotrigger's prediction that Lavos would destroy the world in 1999.

[Enraged Slith]

Man, Harold Camping must be embarrassed about his incredibly poor math skills.

[Actaeon]

Originally Posted By: Excalibur

I always hate it when the world ends on a Friday!

I wonder which day of the week would be ideal? Sunday, I guess, since we'd get a weekend in first, and most of the people predicting it would be off at church, anyway.

[Alorael at Large]

Originally Posted By: Student of Trinity

My fingers are slipping off it ...

Aaaaaaaaaahhhhhh!

I'm a little baffled when people write out their deaths. I'm even more baffled when they write out the scream of losing contact with the device they're using to write.

—Alorael, who wasn't aware that Camping had put the new end of the world today. He could've slept in and missed the whole thing!

[Ceiling Durkheim]

Yup. He amended it after the whole May 21 thing went south.

[Randomizer]

THe world should end Monday morning local time preferably before getting out of bed to get ready for work.

[Aoslare]

Originally Posted By: Triumph

That list on Wikipedia left out Chronotrigger's prediction that Lavos would destroy the world in 1999.

Also, Crystalis's prediction.

[Aran]

Originally Posted By: Mnemonics to remember mnemonics

Originally Posted By: Student of Trinity

My fingers are slipping off it ...

Aaaaaaaaaahhhhhh!

I'm a little baffled when people write out their deaths. I'm even more baffled when they write out the scream of losing contact with the device they're using to write.

It is a fine tradition that I believe Howard Lovecraft started.

Originally Posted By: Enraged Slith

Man, Harold Camping must be embarrassed about his incredibly poor math skills.

You'd think he'd get it right on the sixth attempt...

[Alorael at Large]

Oh? Where does this trope appear in Lovecraftian literature?

 

—Alorael, who is not actually terribly conversant with Lovecraftian horror as written by H. P. Lovecraft himself. He's read some of the stories, but only a small minority.

[The Mystic]

Originally Posted By: Excalibur

I always hate it when the world ends on a Friday!

Look on the bright side: If the world does, in fact, end on a Friday, then you've got one heck of a long weekend look forward to and to enjoy.

Originally Posted By: Polaran

I found one of the most awesome list-type Wikipedia articles in the process of reading about this (I have too much time, apparently). The last decade when the world wasn't scheduled to end were the 1820s. The last decade with only a single scheduled apocalypse were the 1950s. The last item on the page is particularly great.

Cool list. I knew there were a lot of end-of-the-world predictions, but...wow. And I agree, the last one is the best; I also say it's the only one with any amount of truth to it. The frequency of predictions seems to be accelerating, too.

Also, the list is incomplete. Here's a few I've heard that aren't on the list:

• 1998: 1998 = 3 * 666
• September 9, 1999: All computers will crash, because "everyone" knows that the date "9/9/99" is read internally as "9999" and is interpreted by every OS as "end of file"; therefore, no computer will survive past this date.
• June 6, 2006: The date is "6/6/06," which can be read as "666."

[Alorael at Large]

Ah, but the last isn't really a prediction so much as an upper bound. It's also not nearly precise enough. Not even getting it down to a single century? Please!

 

—Alorael, who predicts that the world will end with a bang and[/] a whimper. Also some clanking noises and a kind of wet squelching.

[Student of Trinity]

If I remember this rightly, stars enter red giant phases after the hydrogen in their centermost region has all been fused into helium. The counter-intuitive thing is that this has the effect of making the star start pumping out energy much faster than before.

 

A star doesn't run out of hydrogen everywhere all at once. The rate of fusion is fastest in the very center, where the density and temperature are highest. Further out, the density and temperature are too low for any fusion; most of the star is not fusing at all, just the core. But hydrogen fusion stops in the center first, and continues for quite a while a bit further out in the core, where fusion has been slower. This is where it gets interesting.

 

Once a star's innermost core has become just an enormous inert mass of helium, that central part gradually shrinks to higher density. As the central core shrinks, the gravitational force it exerts on the surrounding layers of gas gets stronger, simply because everything is getting closer together. So the outer core layer that is still fusing hydrogen get pulled inwards, and its density becomes much higher than it ever was before. The result is that the star fuses much faster than ever before, because it is fusing now in a dense shell layer around the denser inert center. The inert center is in effect super-charging the star's fusion.

 

The much greater energy output blows the star's outer layers out to much greater radius than before; the star becomes a 'giant'. The way the details of pressure and temperature versus gravity work out, the star becomes so much bigger that its outermost surface layers actually become cooler than ever before, even though the star's energy output is now higher. (Total energy output is proportional to surface area — a much bigger cool star can radiate more than a smaller hot one.) The star becomes 'red' instead of the yellow or bluish white of hotter star surfaces.

 

So that's the basic difference between red giant stars and normal stars: the central core is inert in a giant, so the extra confinement force from the inert core's gravity compresses the fusing region to higher density, pushing up the energy output. Bizarre, eh?

 

The giant star's future from this point is a race between two things: running out of hydrogen even in its fusing shell, and heating the inert central core. If the shell stops fusing while the center is still inert, the whole star just dies. It stops fusing entirely, and slowly shrinks into a so-called white dwarf. But if the star is big enough, its inert core will first get hot enough to initiate helium fusion, and the star gets a new lease on life.

 

This will actually make the star's energy output drop dramatically again, because the now active core will push the dense outer layers back further out, lowering their density, and dropping the high rate of fusion back down to normal stellar levels. The giant star will shrink back down to normal size, and go back to a brighter color, too.

 

Really big stars can go through many cycles of this, fusing their way gradually up the periodic table. They may peter out at various stages, depending on their size. That's why there was news a while ago about astronomers detecting a white dwarf that they believed was made mostly of carbon, and hence might well be a diamond with the mass of a star. If a star gets all the way up to having an iron core, though, that's the end of the road, because iron is the most stable nucleus. Fusing iron into heavier elements doesn't release energy, but rather costs energy. It does happen as a side effect of stellar fusion, which is how all the heavier elements got formed, but it's no way for a star to stay in business.

 

For some reason stars that grow big inert cores of iron tend to blow up as Type II supernovas, rather than gently subsiding into white dwarfs. I can't remember why they go so violently just because they've completely run out of nuclear options. Our sun won't do that; it's too small to make it past fusing helium. But the period as the central core goes inert and starts to collapse will still probably be rather violent, if I remember the theory right, and that's what will probably destroy the earth. Or maybe the sun will just gradually expand until earth gets slow-roasted to a crisp, over millions of years.

[Necris Omega]

By science or religion, we're all doomed...

 

Actually, no, I take that back, as I don't really have a good grasp on whether or not some of the far Eastern religions have their own "apocalypse". Buddhapocalypse? ...

[Kelandon]

Originally Posted By: Student of Trinity

For some reason stars that grow big inert cores of iron tend to blow up as Type II supernovas, rather than gently subsiding into white dwarfs. I can't remember why they go so violently just because they've completely run out of nuclear options.

If I remember correctly, once there's no fusion to push outward, gravity pulling everything inward wins again, and all the mass starts to fall towards the center. But it slightly overshoots equilibrium, and there's a bounce back outward, sort of like dropping a basketball on the ground and letting it bounce back up.

The problem is, as I recall, that we don't really get how the bounce works. It has something to do with the strong nuclear force, if I remember correctly, but we don't know enough of the detailed parameters to make our computer simulations actually explode outwards.

My professor said that he avoided that area of research as much as possible, because it involved essentially no conceptual breakthroughs, but just tinkering with things at the margins until finally the right tuning gets the explosion.

[Micawber]

It's 99% certain your prof is correct and it's a dead end. However, apparently we don't know everything about stars yet.

[Alorael at Large]

Buddhism doesn't have an end of the world scenario like Western religions. Hinduism has cyclical time (on a several billion year scale!), and at the end of the present age the universe will end and be reborn.

 

—Alorael, who could see fundamentalist Hindus taking this as Biblical-equivalent evidence for a Big Crunch.

[Rowen]

I thought the end of the world comes for everyone at different time and we called it death.

[Student of Trinity]

I think that's right. The end of the world is a comforting thought. It means you're not missing out on anything. The more likely and uncomfortable scenario is that we die, and the world and other people go on, much as they did before, only without us.

 

There's a great short story by Jack Vance, whose title I forget, about a tropical island under a strong and constant trade wind. Among the people who live there it is the custom that anyone who begins to feel old builds a sailing canoe and leaves, though the wind will prevent them from ever returning. The leaving is entirely voluntary, and some take much longer to come to it than others. The custom is at first presented as bizarre and arbitrary. Groups of young friends regularly pledge never to observe it. But one after another, for one reason or another, they all end up leaving. Some are somehow disappointed, others just grow bored or curious. Even the ones most determined to stay yield eventually, when their friends are all gone, and it becomes clear that the younger generation around them considers them irrelevant.

 

The story is not really an allegory. A few days sail downwind there is mainland, and the middle-aged islanders arrive there to find a place less paradisiacal than the home of their youth, but quite livable. Only there do they learn about old age and death. The point of the story seems to me to be that leaving the world you know, on a one-way trip into the unknown, can become inevitable, even when mortality itself is not an issue. Somehow the world is always ending.