The Big Rip

WolfWithoutAClause writes "It's been known for decades that the universe is expanding. The current evidence points to this rate of expansion increasing, and if so, there's no obvious reason why the expansion rate couldn't continue to increase ever faster. A physicist, Simon Caldwell, has taken this to inevitable conclusion and suggested the expansion will eventually reach a point where the expansion rate is so high that any surviving people will ripped apart, followed a millisecond later by the destruction of all the atoms in the universe. Ouch. New Scientist says we may only have 22 billion years left. Almost enough time for a quick game of Everquest then."

Comments

And then the lawsuit will come...

[phamlen]

Hmmm... if I read this correctly, the universe will be "ripping" all the digital media in existence in about 22 billion years.

Sounds like it could be the target for a RIAA/DCMA lawsuit! "Your honor, we would like to sue the universe for clearly premeditated copyright violation."

Don't Panic!

[Lemmeoutada Collecti]

Given that humans have been on Earth only a few million(?) years, is this even something woth worrying about at this point?

Given that as a scientific line of inquiry it is interesting, it is nothing more at this point than another pet theory based on abservations made of a (very) limited part of the universe, so I take it like all such with a grain of salt.

Re:Don't Panic!

[WolfWithoutAClause]

so I take it like all such with a grain of salt.

Yes, a large one; and getting larger all the time ;-)

My Results

[scotay]

the expansion will eventually reach a point where the expansion rate is so high that any surviving people will ripped apart, followed a millisecond later by the destruction of all the atoms in the universe.

My experiments in expansion have proven that somewhere around a 44-46 waist the expansion rate is so high, you better start looking for a big-and-tall men's shop or any surviving jeans will be ripped apart, followed a millisecond later by the purchasing of sweatpants.

Don't let this happen to your universe.

Shot in the dark

[Darkstorm]

What I find so amazing is that half the theories are created on so little real fact. Just recently scientist have acknowledged that dark matter/energy exsist. But they have no clue what it is...or how it works...or how to include it in thier equasions. So they guess, start dropping it into the mathmatical grinder and presto...instant theory of the univers ripping to pieces.

I wish they would wait at least long enough to get some decent information on new discoveries before twisting them into imaginary shapes and trying hard to get recognized.

Re:Shot in the dark

[You're All Wrong]

Probably true within the bounds of the situations the experiments were testing, yes, probably. That's _interpolation_ and is pretty safe for most physics.

However, making prediction what happens outside those bounds is _extrapolation_, and almost all extrapolation is wrong.

Newtonian laws of motion? Extrapolate to high velocities, and you incorrectly predict the orbit of mercury. (Add SR to fix.)

Classical models of black body radiation? Extrapolate to very short wavelengths, and you get the ultraviolet catastrophe. (Add Planck to fix).

However, all these fixes still have _their_ bounds, and you can't use NM+SR to predict behaviour of particles small-enough to have wavelike behaviour.

Extrapolation is what you do when you desperately need more funding...

YAW.

Re:New Scientist

[Goldsmith]

Black holes have already been shown to "evaporate". That's Stephan Hawking's claim to fame really. Basically, by using conservation of energy and quantum mechanics, he was able to show that black holes would convert mass into very high energy light waves, which would then tunnel out. Small black holes could then potentially evaporate away.

The dangers of extrapolation

[phamlen]

Mark Twain wrote on nearly this exact topic in 1883. He wrote a great essay on extrapolation , basing his conclusions on the fact that the Missippi between Cairo and New Orleans was shortening an average of a mile per year for the last two hundred years or so....

To quote:
"Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oolitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upward of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."

-Peter

The Joy of Extrapolation

[You're All Wrong]

"A physicist, Simon Caldwell, has taken this to inevitable conclusion and suggested the expansion will eventually reach a point where the expansion rate is so high that any surviving people will ripped apart"

What did Master Caldwell think when he first started getting his first erection?

Sorry for being crude,
YAW.

Re:New Scientist

[looseBits]

The other mechanisim for black whole evaporation concerns virtual particles. If a e-/e+ pair get created right on the event horizon, the positron can possibly fall beyond the horizon and the electron could escape. The positron would then destroy an electron inside the backhole and decrease its mass. The reverse situation is forbidden as the electron wouldn't be elliminated inside the black whole and the positron may exist for a decent amount of time before coliding with another electron, thus breaking dE*dT = Hbar.

That's the way I understand but I may be an idiot.

The actual journal article

[Noren]

The journal article that the New Scientist article has made a journalistic hack job of is here. The actual article is not presented as future history; it presents a possibility, a consequence of making an explicitly stated assumption about the nature of dark energy (about which very little is known.)

I also wish to point out that extrapolation can be useful for precisely the reason many are criticizing it: it can reveal where current theories are wrong.

Universal expansion doesn't mean *we* expand!

[astroboscope]

Any reasonably dense collection of matter (like a planet, our solar system, and our galaxy) is gravitationally bound and stays together. Universal expansion means that the galaxies get farther apart, not that they get bigger.

Shame on New Scientist.

And now the above, with (a little) math. The gravitational force between two objects is basically (leaving out mass)

F = -k / r^2 + L * r

where k is a constant, r is the separation between the 2 objs, and L is either a constant or a function of time (we don't know yet).

The k term is good old Newtonian (or even Einsteinian up until a couple of years ago) gravity. Strong for small r, weak for low r.

The L term represents the new discovery that the universal expansion is accelerating. It is (unnoticeably) weak on small scales, and only important for large r (i.e. size of the visible universe). For the L term to matter on planetary scales, it would have to become much larger in the future. But we just discovered that it even exists - how it behaves with time is the next thing to find. So don't worry (yet ;-).