NASA: Evidence Favors Infinitely Expanding Universe

Chris Gondek writes "The Sydney Morning Herald has a story here about how NASA is expected to announce this week that it has proved the existence of "dark energy," a cosmic force that counteracts gravity and will keep the universe expanding forever. The announcement will effectively demolish the theory that life will be wiped out in a "big crunch" when the universe collapses, and should end decades of academic dispute. Scientists ranging from Stephen Hawking, the Cambridge University physicist, to Albert Einstein, have argued that the universe eventually will stop expanding and then implode under the force of gravity, destroying all life. The Chicago Sun Times has also got some info."

Comments

Heat Death instead

[crow]

So instead of the Big Crunch, we get Heat Death. The universe is slowly cooling, and will eventually cool to absolute zero (killing all life), or so the theory goes.

I don't think that there is any reputable theory that doesn't have a "killing all life" at some point in the very distant future.

Heat Death... unless

[meckardt]

What will remain is a universe full of black holes, which after trillions of years will explode to leave nothing but dark energy.

This is true... unless there is another mechanism that transforms some of the dark energy back to normal matter. This could result in a classic steady state model.

Re:Perception is reality

[KDan]

Expansion of the universe doesn't actually mean the space between the atoms in your body increases. The atoms in your body are tightly coupled by strong electromagnetic forces, which are stronger than the expansion of the universe. Imagine a cardboard disc on the elastic surface that usually represents spacetime - several cardboard discs will grow apart as you stretch the surface, but the discs themselves will not grow, they are rigid because of the internal forces.

Those discs are actually of sizes somewhere around clusters of (billions of) galaxies, so the atoms in your body are fairly safe.

Daniel

The Standard View of Gravity

[ka9dgx]

When you get down to it, the problem that people have is that observations of large systems don't seem to experience gravity the same way we see it locally here on earth.

The assumption is that the laws of physics are uniform throughout the universe, which I also assume to be true. However, I don't assume that gravity is an attractive force, but rather one that obeys common sense, and is repulsive in nature at the quantum level.

I believe that when a graviton interacts with a particle, it pushes it along... just like any other particle interaction... but I believe that the source of the gravitons is external... and that each interaction creates a shadow... thus there would be slightly more gravitons coming at be from above, than have managed to pass through the earth to hit me from below... thus creating an apparent (and real) local gravity field, with the deficit in the downward direction.

The experiments to prove this are going to be very sneaky... but one sure proof would be that a material that stops gravitons would be very heavy, instead of having a negative weight. Even if you managed to stop some of the gravitons... then effects would be on the opposite side of the device than expected. Thus if your anti-gravity plate is put underneath a weight, it would actually get heavier... and if you put it above the plate, then it would get lighter.

The truely interesting effects occur when you get black-hole level matter density. If I'm right... then they should probably "boil off" slowly as some of the matter gets pushed out of the hole over time.

--Mike--

Re:Whew! That's a relief!

[Forgotten]

It's kind of a funny term. Heat death is actually the complete conversion of all the free energy in a system (in this case, of all systems) into the corresponding entropy. It's the victory of the second law of thermodynamics. It's not that all the energy goes away, but that it becomes so evenly spread that no further work is possible - there are no more free energy gradients to traverse. So it's not the death of heat, it's a death in heat - literally a tepid cosmos. ;)

As I noted in another message, an infinitely expanding universe means that the temperature of the heat-dead cosmos will constantly drop as the volume increases. It will asymptotically approach absolute zero.

Some others have noted that there are theories where energy and/or matter are spontaneously created in empty space. These can coexist with the heat death fate if the new energy is also evenly spread, which it probably would be in such a uniformly boring heat-dead universe. Still no way to create a new free energy gradient.

I find this an interesting fate because it's also reflected in some religions and philosophies, where everything becomes one at the end of time.

Dark energy

[ajdecon]

NASA definitely will not announce that they had proven the existence of "dark energy"; all they can really announce is that data they collected suggests an infinitely expanding universe. (This would not, btw, require dark energy, though an accelerating universe might; all it would require would be for the total matter and energy in the universe to be below a certain threshold level.)

I don't really know a whole lot about "dark energy" at this point... a few mentions here and there have given me a murky idea of it as similar to Einstein's cosmological constant, but nothing really definitive. Some recent evidence does, I believe, suggest an accelerating expansion which could lend credence to the theory... but I believe there have been alternative hypotheses advanced as well.

I am not a physicist, however, merely a freshman physics major. ;-) I know the NASA announcement isn't out yet so primary sources on this particular experiment are hard to come by, but can anyone suggest some background or current research on dark energy and the cosmological constant? My only real source so far has been Scientific American--that is to say, I've got no reliable sources. [grimace]

Much appreciated....

Re:Then how did the Bing Bang happen?

[EvilTwinSkippy]

Turning a switch on in systems equations requires an infinite amount of energy. Think about that the next time someone tells you to switch the lights off if you aren't in the room for 5 minutes.

Seriously though, I think every cosmologist should be required to be an Electrical Engineer first. I should write a book, All the I needed to know in life I learned in Systems

• All of the mathmatical rules we have to describe the universe are approximations.
• There is more than one model to describe most phenominon.
• Any time you convert data, you alter it. Quantifying data is a conversion process.
• Quick, Cheap, Right. Pick any two.
• If the problem can't be solved, transform it into another domain or eliminate variables through constraints.
• And by the way, just because someone says it's a constraint doesn't make it so.
• Engineers are the center of the Universe. They get to pick the coordinate system.

They need to address Halton Arp's observations

[Kelvin]

Halton Arp, an award winning astronomer who used to be Edwin Hubble's assistant, has spent years documenting physically connected astronomical bodies with vastly different redshifts. That's simply impossible under the current theories. But they exist.

He's published several books on the subject including Seeing Red: Redshifts, Cosmology and Academic Science which presents considerable information that's been surpressed by astronomers whose theories have been threatened.

In Seeing Red, he also lays out an alternate, simplified theory, which is a _slight_ modification of the general theory of relativity that ends up predicting the real world observations without resorting to magic constants, curved space, "dark matter", and other kludges that the currently accepted theories need.

Here's some other info about it.

Re:Then how did the Bing Bang happen?

[Jester99]

This concept of multiple universes makes absolutely no sense to me; doesn't, by definition, the universe mean "everything"? Hence, if multiple time/space continuums existed, they would just constitute different parts of the same universe?

The best way to think about it is to imagine a balloon. Blow the balloon up. See the inner walls of it? That's the universe. You can place a pebble anywhere on those walls and roll it around, and it's pretty much trapped there.

Our universe (theoretically, anyway) is a special, 3-d balloon wall. Supposing the inner walls of the balloon were 3d, you could travel around in there, but never escape.

Now take hold of some of the balloon in one hand, so you've pinched off a sub-balloon. Give the pinch-point a small twist so it stays that way. A pebble rolling around on the inner surface of that pinched off bubble will never make it into the original balloon inner-space. They're connected, but it is impossible to get from one "universe" to the other. This is what is meant by the multiple universes sprouting off from each other theory. Singularities in space, etc, cause baby universes to "pinch off" from the one we know and love.

Disclaimer: IANAPP (I am not a particle physicist), but I've read a few books / magazines on the subject :)

That's how I think about it, anyway.

Re:Unfortunate

[LMCBoy]

Even if we don't live in a closed, oscillating Universe, it's still possible that the Universe could "reboot" itself after the heat death. [Disclaimer: complete speculation follows. I am an astronomer, but by no means am I a cosmologist]

If we live in a non-oscillatory universe, then the Big Bang was not a "bounce" due to a preceeding Big Crunch. Rather, the Big Bang arose from a quantum fluctuation in the vast nothingness that was (or was not?) before. So, if the Universe of the very distant future has expanded to ~zero density and ~zero temperature, then it looks basically just like the pre-Big Bang vacuum. In that case, another Universe might very well pop up from another quantum fluctuation in the vacuum.

Hell, who knows? Maybe a sufficiently empty vacuum is extremely unstable to such Universe-spawning fluctuations, so they are pretty much certain to occur once the density and temperature get low enough. If so, there you go: we can have our heat death and still have Universal rebirth.