NASA: Evidence Favors Infinitely Expanding Universe 689
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."
I don't know about you... (Score:4, Funny)
Re:I don't know about you... (Score:2, Interesting)
Re:I don't know about you... (Score:5, Insightful)
Clarifications (Score:3, Informative)
That's the old (early 90's) model. Before the supernova data, we thought that the universe would be decelerating. However, now we're pretty sure that the universe is accelerating, not decelerating.
However, that doesn't mean that the universe won't decelerate later (or didn't decelerate earlier). There are still a lot of questions as to what the dark energy is and all of the accelerating/decelerating depends on what it is.
Google for quintessence. It's beyond my area of expertise.
Regardless of what the dark energy actually is, the universe is accelerating right now.
Re:I don't know about you... (Score:3, Interesting)
Yeh, but that is only how we look at things here on Earth, within enough of a margin of error, things at infinity, etc, do not matter to us for our purposes and applications. However, if you are looking at this in a purely classical physics matter and on the universal scale, then the momentum caused by the big bang, that is the movement of the universe now, can only continually be proppelled by further explosions. But the explosions have reactants and products, and pretty soon the reactants will run out (I would guess that the source of reactants is not infinite, just as any fuel that we know of is not infinite - whether it be for the Sun or for our cars). This means that further impulses will not occur to continually increase the momentum over infinite time. And, since gravity acts an infinitesmal force at even infinite distances, then in the end, gravity will always overcome the momentum, and the universe will have to crunch back in on itself.
And actually, if you look at it in this way, it sort of makes sense. The universe is just one big oscillating process, the origins of which we have no grasp of yet (through the sciences, the religions have explained this for a while now). But, we can imagine that if we just begin to look at the universe at some random point in time, it is either expanding or contracting. If expanding, a big bang has just occured, and the universe will continue to expand until the energies of expansion run out and the energies of contraction take over (ie Earth analogy: kinetic vs potential energies when throwing an object upwards). Then, when contraction energies take over, the universe will contract and collapse on itself, increasing temperatures, pressures, etc, and the result is another big bang that resets the universe to the original state that we observed it in: expansion. Lather. Rinse. Repeat.
This would lead us onto another big question though: where the heck did all this start from? Has the universe just always existed and the absence of a surrounding (in thermo terms) resulted in a process/cycle that has thermo properties that are entirely conservered (constant on the whole). But then, why would the universe exist in the first place? Perhaps our universe is just the surrounding for thermo processes in other dimensions? Who knows. It would be fun to get in a time machine and travel 100, 1000, 10000, 100000, then 1000000 years into the future and see what we have come up with and if we can explain anything any better (although I'm sure we'll have come up with many more details in the mean time, but will we really understand the origins of time and the universe then?).
Re:I don't know about you... (Score:3, Insightful)
Perception is reality (Score:4, Funny)
Re:Perception is reality (Score:5, Interesting)
Those discs are actually of sizes somewhere around clusters of (billions of) galaxies, so the atoms in your body are fairly safe.
Daniel
Good Sigmonster! (Score:2, Funny)
The universe is like a safe to which there is a combination -- but the combination is locked up in the safe. -- Peter DeVries
Now all I have to do is find out how to emit this energy and I can build starships!
Hollow Universe (Score:3, Insightful)
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.
Maybe a little Robert Frost too... (Score:5, Funny)
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
Re:Hollow Universe (Score:5, Informative)
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.
from "The Hollow Men", TS Eliot.
Attribute your sources!
--Jim
"end decades of academic dispute" (Score:2, Insightful)
Re:"end decades of academic dispute" (Score:3, Insightful)
Note that this will make the creation debate more intense since now it could be argued that if it expands forver there had to be a fixed point in time when it began and therefore something had to cause such a beginning.
The debates over what caused the beginning are about to get a lot more interesting.
Whew! That's a relief! (Score:5, Funny)
What a relief. I was worried.
The universe will be wiped out by the heat death of the universe instead.
(Or am I incorrect in my understanding?)
Re:Whew! That's a relief! (Score:2, Informative)
"Although NASA's discovery means the universe will go on forever, the same is not true for human life. As the universe expands, all of its energy will be used up."
Re:Whew! That's a relief! (Score:2)
Re:Whew! That's a relief! (Score:5, Interesting)
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.
Re:Whew! That's a relief! (Score:4, Insightful)
Are you talking about how there is no global energy conservation due to time assymetry and Noether's theorem?
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.
Don't most religions postulating "one" at the end of time actually have something closer to the big-bang / big-crunch? I mean the final conflagration in Heraclitus on up through the Stoics seems to have much more in common with the earlier view of cosmology. The big cruch returns everything to fire = logos that was had at the beginning of the universe. In this view the fire is raw energy and information.
I don't know of anything in traditional philosophies or religions that really corresponds to the heat death of the universe.
Re:Whew! That's a relief! (Score:5, Insightful)
I think that Buddhist Nirvana sort of does; entities that become enlightened are never returned to the wheel of life, so there's a constant drain of energy "lost" by the world to nothingness. The peace of Nirvana always seemed something like a perfectly uniform universe to me. Eventually everyone on every plane is enlightened and everything is just sort of frozen (which is a way of looking at heat death, complete equilibrium being equivalent to no motion at all).
On the other hand Taoism would propose a universe that expands back into the original version of itself, since everything proceeds through an extreme, into and through its opposite, and back into itself. That's broad enough that you could fit either a big-bang-big-crunch, or a heat death where something about the uniform state causes the return of extreme nonuniformity (which is entirely possible, see below).
One of the things I find provocative about the heat death and "big egg" fates is that they're at some level indistinguishable. Once the universe is uniform, both time and space becomes meaningless, just as they do after a big crunch. So the Taoist view makes sense to me - the universe really does find its opposite (and a rebirth) at the extreme ends of time.
Oh well. I really have things I should be doing today besides discussing cosmology, if I'm to be able to afford to keep converting free energy myself. ;)
Re:Whew! That's a relief! (Score:5, Insightful)
I wouldn't get too excited, though. There are virtually no "facts" in cosmology that haven't been overthrown multiple times. This one will be no different.
Re:Whew! That's a relief! (Score:2)
Daniel
Re:Whew! That's a relief! (Score:5, Funny)
Reminds me of the story of the student of cosmology who frantically waved his hand until the annoyed professor finally called on him.
"Professor, would you mind repeating what you just said about the end of the universe?"
"I said that according to recent estimates it would take place in about 200 billion years."
"Oh, thank God, you really had me worried there for a minute! I though you said million!
What I want to know is... (Score:5, Funny)
How the hell can they predict what the universe is going to do in trillions of years, but I can't get an accurate weather forcast for the next 24 hours??
Well, that's that then... (Score:3, Insightful)
Hmm, yeah, well this is the first time someone has definitively claimed to have proven the answer to this issue. I don't really expect there to be any more back and forth on THIS one...
Damn, now we know the speed of gravity and the color of the universe, what's left? Let's shut down the patent office, man, science is done! Progress is so awesome - I think I'll just kick back in this technoparadise we've created until entropy consumes all things.
Indeed (Score:3, Interesting)
Ah crap (Score:4, Funny)
Sun Times? (Score:2, Funny)
Re:Sun Times? (Score:3, Funny)
Heat Death instead (Score:4, Interesting)
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.
Re:Heat Death instead (Score:2)
Opposing that is the theory that any sufficiently large empty space starts spouting matter (sounds like spontaneous creation, doesn't it?). This is apparently an attempt to explain the 'foamy' shape of the observable universe.
Re:Heat Death instead (Score:2)
Perhaps there are reputable theories that have "killing all life" in the not-so-distant future?
;-)
Re:Heat Death instead (Score:5, Funny)
Thus finally allowing Mickey Mouse to pass into the public domain.
Omega Point (Score:3, Informative)
Check out the Omega Point Theory [tulane.edu]... in this book [amazon.com]. It suggests a way to use the expansion of space to generate energy to run a computer that would contain everyone's' information. Seems plausible, until he mixes its up with religion and it turns metaphysical. This theory has been promoted by Tipler, the same guy who has written many physics text books [amazon.com]. I don't but the theory, but it answers your question about an alternate theory...
Re:Heat Death instead (Score:3, Interesting)
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.
Dyson said, more or less, that life can store up some energy and wait for the universe to cool. Then it can use that difference in energies to do some useful work, and wait for the universe to cool again to the point where the difference is sufficient to do an equal amount of work. He proposes that life can do this indefinitely (I guess because energy difference is a continuous curve function against time? But IANAP.)
Love the last paragraph (Score:2, Funny)
Although NASA's discovery means the universe will go on forever, the same is not true for human life. As the universe expands, all the energy needed to keep the stars and galaxies alight will be used up. What will remain is a universe full of black holes, which after trillions of years will explode to leave nothing but dark energy
Grain of salt post. (Score:3, Insightful)
This is the typical "blackbox" approach in science:
You have a blackbox with inputs and outputs, and you theorize what is in the blackbox based on your inputs, and what the outputs are. Sure you can come up with math/thoery that works everytime when trying to predict what the blackbox DOES. But this doesn't mean you really know what the blackbox IS (or whats inside rather).
Losely throwing out a word such as "dark energy", pretty much spells "we really have no fucking clue why to me".
sure there is something forcing our universe to expand againts the will of gravity. But it's OK to admit we don't know what it is.
Heh.. I might as well call that sludge in my sink "dark matter", and the unpleasant odour a result of "dark energy".
--noodle
Re:Grain of salt post. (Score:4, Insightful)
Why? It's just as good a term as Einstein's cosmological constant. It's just a label.
And the "blackbox" approach is part of figuring out what is going on. We don't know how gravity works. Does that stop us from knowing that it does work, or what effects it has on the universe? This is no different.
If we had to wait until we had a nuts-and-bolts answer for every question we'd never get anywhere.
Re:Grain of salt post. (Score:2)
A bit more than a black box in my opinion.
Sure, electron or energy or dark energy are labels for bits and pieces in theories, but that doesn't mean that the concepts which they label are not valid and observed. A good example of this is quarks - you could ask "how do they know the stuff inside hadrons is quarks?" They don't, per se. What they know is that the stuff inside hadrons has a certain number of characteristics, and that's the characteristics that describe what we call "quarks". All of physics is like that, but that doesn't make it any less useful or insightful.
Daniel
Re:Grain of salt post. (Score:5, Insightful)
No Omega Point? (Score:3, Interesting)
not so new... (Score:3, Informative)
Unfortunate (Score:3, Insightful)
Re:Unfortunate (Score:4, Interesting)
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.
Heat Death... unless (Score:4, Interesting)
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:Heat Death... unless (Score:4, Funny)
"Let there be light"
Re:Heat Death... unless - funny? (Score:3, Informative)
Anybody remember the Asimov short story, name escapes me, with the central computer that answered questions, and from time to time different generations would ask it "How can entropy be reversed?"; every time the answer was "There is as yet insignificant data to compute an answer." Eventually, mankind dies off and leaves this multidimensional hyperspatial uber-computer, which is left with one unanswered question, and it churns away, until the Universe reaches the end, heat death...and this computer finally gets the data, and the answer, and it booms out..."Let There Be Light".
Re:Heat Death... unless (Score:2)
I couldn't agree more. So far in human learning we have found that for every action there is a reaction, for every particle an anti-particle, every good an evil, every yin a yang.
Everything in the universe from stars to atoms, amoebas to anteaters goes through some cycle of death and rebirth. Why wouldn't there be a counteractive mechanism to the expansion of the universe? I for one trust the amazing design of the universe to have already accounted for this problem. We just have to figure it out.
END Academic Dispute? (Score:5, Insightful)
There's never one simple explanation to something in a scientific field; there is simply the explanation which has the most evidence supporting it.
Re:END Academic Dispute? (Score:3, Insightful)
Daniel
Simple explanations... (Score:3, Insightful)
Genetic diversity comes down to DNA.
Odds are that the simple explanations are the best. Who knows maybe one day it will turn out that the answer really is 42.
Then how did the Bing Bang happen? (Score:4, Insightful)
So, How did the universe get created. Does this mean that there was actually a "beginning of time" as far as we can tell? What was that point? What existed before then? Since matter can't be created nor destroyed, where did it come from? (though that is a question beyond most planes of though, IMO)
I don't believe this story, and I think more research is needed here.
Re:Then how did the Bing Bang happen? (Score:5, Funny)
He was a very good crooner.
This is how, not "The", but many, Bing Bangs happened.
Badda Bing (Score:3, Informative)
Re:Then how did the Bing Bang happen? (Score:2)
Using words like "created" in reference to subject matter which involves time is self-defeating.
The "point" and "what" existed "before then" is all really just asking for the answer to the life the universe and everything.
Religion and science are orthogonal. Science can answer how the universe formed and how mathematical models can define time and space, but it can't answer "why."
Re:Then how did the Bing Bang happen? (Score:3, Insightful)
Much of your question is not relevant in this discussion, as the Big Bang theory attempts to explain what happens in our universe, not before it!
I'm getting confused (Score:3, Funny)
Re:Then how did the Bing Bang happen? (Score:4, Insightful)
Secondly, from my understanding, the Big Bang complements the Inflationary Model. Everything started accelorating from a giant explosion. But as the galaxies got further apart, the void between them tended to increase it's size. This is the mysterious "inflation" force that keeps galaxies accelorating away from each other.
There must be such a force if everything keeps expanding forever. Imagine that Earth is the only object in the universe, and someone throws an apple straight up so that it does not fall into orbit. Eventually, no matter how far away that apple gets, it will come back to Earth. That's because there is nothing accelorating it away from Earth, and gravity pulls it towards Earth. In order for the apple to keep increasing it's distance from Earth, something must keep pushing on it.
The thing that keeps pushing it is the inflationary force, or, alternatively, the cosmological constant. It does not explain the origins of the universe, but rather it's fate. So it is irrelevant to a question of "the beginning of time."
Re:Then how did the Bing Bang happen? (Score:5, Interesting)
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:Then how did the Bing Bang happen? (Score:5, Interesting)
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
Re:Then how did the Bing Bang happen? (Score:4, Insightful)
Let's say I, as a supreme being, throw a rock, connected to my hand by a piece of magic string into the void. And lets say life evolves on this rock to the point where it is has figured out that it came from "the big throw." The big question for everyone on the rock is: Is the magic string
a) taut? (static Universe)
b) forever stretchy? (infinite Universe)
c) rubberbandy? (big crunch Universe)
You seem to like c) which I agree sounds very nice, because then life can be seen as an infinite bounce of "big throw, expand, crunch, repeat."
But just because someone comes up with a good theory for b) doesn't mean I didn't throw the rock in the first place!
Maybe this is the first rock I've ever thrown? I guess I'll never throw another one. I hope nobody has a problem with that.
Or, maybe I'll just throw another rock with one of my infinite hands (ah, the multiverse concept)?
Point is: yes, there can be a big bang AND a forever expanding universe.
P.S. What you want to believe about "before" the big bang is a metaphysicial question, because time and space began at the big bang. You might as well be asking "what is north of the north pole?"
Depressing news. (Score:2, Interesting)
They can prove it? (Score:5, Insightful)
This theory has been around for a while. I believe Scientific American ran an article a couple of years back about some work done on distant nebula and using the redshift, they were able to determine that they were accelerating away from us.
It really doesn't matter one way or the other, because in the end, all the fuel for the stars will burn up and there won't be a light in the universe, let alone life.
I don't know enough to be sure, but black holes apparently decay into real particles via virtual particles at the event horizon, but I believe these are just electrons and positrons.
So, if eventually once all the hydrogen is gone, the only way for life to go on would be to find some way to create hydrogen from the heavier atoms from older stars and whatever has decayed from black holes. While I don't think that that's impossible, given the billions of years of advancement we have, you also need some source of energy to create the hydrogen, and eventually you're in a catch-22 where you need the energy to create the hydrogen so you can make a star to give you energy. Hmm..
Okay, I'm rambling a bit. Cool topic, though.
Science doesn't prove anything. (Score:3, Informative)
Science can never claim to prove any theory, only disprove it. Sure, some theories work so well that people think of them as fact, sometimes even dogma, but the point of science is to make a theory, and test it by trying to *disprove* it. Theories become more accepted when they make predictions about what will happen, and experiments *verify* (not prove) that they (the theory) is correct (on that point).
Mathematics, on the other hand, can be built upon theorems, lemmas, and axioms (etc), which can be proven true. Science cannot. Many people make this mistake.
Thats comforting (Score:2)
Boy am I going to sleep better now.
-Sean
Hmmm... (Score:2)
destroying all life (Score:2)
Are you implying an expanding universe will give perpetual life? I'm not exactly sure how any life could be sustainable in an expanded universe where an eletron's orbit around an atom is greater than the size of our current solar system.
Re:destroying all life (Score:2)
Quick, buy as much stock in Weight Watchers as you can!
Either way (Score:2)
Re:Either way (Score:2)
"should end decades of academic dispute" (Score:5, Insightful)
The body of greek philosiphy ended decades of dispute on the nature of the universe, and they ended up with an Earth-centered solar system, with crystalline spheres on which were mounted the moon and stars.
The Judeo-Roman Catholic Church ended decades of dispute on the nature of the universe, and they ended up with an Earth that was not only the still center of creation, but that had been created in six days.
Galileo ended decades of dispute by noting that th Earth was not the only body with stuff rotating around it. He was shown the instruments by the aforementioned church and was strangely quiet for a great deal of time afterwards.
Copernicus came up with the sun-centered solar-system, ending decades of dispute (sure he did).
Newton followed a little bit later and ended decades of dispute by using algebra and calculus to describe the paths of the planets.
Einstein followed and ended decades of dispute by using even higher math to describe the way motion worked at its fundamental levels.
Bottom line. We know a lot about the universe. We will continue to dispute and argue what we don't know and there will *always* be stuff we don't know. What good minds will know centuries from now will make us seem just a primitive as people who beleived the sun revolved around the Earth.
Misleading initial sentence (Score:3, Interesting)
The alternative (omega greater than one) implies the end of the universe in the heat death. This is honestly substantially less pleasant, aesthetically speaking, than the alternative. At least to me. Not that this should dictate our ability to weigh the evidence, just pointing out that it's not like we should all be wiping the sweat off our collective brows with this.
On the positive side, if there really is a large scale antigravity force, and we ever figure out how to harness it, that would be pretty sweet.
I knew it.... (Score:2)
Don't worry, you're still doomed. (Score:2)
What will they call it? (Score:4, Funny)
Perhaps and Perhaps Not (Score:3, Interesting)
Yes, the point is to stop academic dispute.... (Score:2)
Wanna bet? That's what was said about quantum mechanics. Yep, we better close up shop! That's what was said about Plate Tectonics. Yep, that's the answer. Guess what? It wasn't (or was it???). We
Oh, NASA said it, it must be right. (Score:2)
Sounds Like the Stock Market (Score:4, Funny)
Still doesn't save us (Score:2)
Rotational Inertia. (Score:2, Interesting)
They try to get me to accept the big bang.. but the problem I see is if everything emanated from a point source, it should not have any rotational inertia, which will be required for the spin I observe.
Maybe our observable universe is the result of the explosive contraction of a black hole? Let me elaborate: A black hole forms, and begins to accrete matter. But the matter is not falling *directly* into the hole, no, it goes round and round on its way in, going ever faster as it falls inward, spinning the hole up. Consider under the rotational centrifugal forces, the singularity forms a ring. Eventually, this ring meets the event horizon. Now, as long as the ring is not spinning fast enough to meet the event horizon, the hole is stable, but once the centrifugal force of the singularity exceeds in the tiniest amount the gravitational force holding it together, it looks like it may detonate, much like a wheel would detonate if you spun it faster than the tensile strength of the steel it is made of exceeded.
This would form the local areas we see in the universe as galaxies and galaxy clusters... and as a result of the rotational inertia of the detonating black hole which formed them, they would rotate likewise, and eventually the cycle would repeat. Endlessly. Much like a pendulum - free of friction, constantly exchanges kinetic energy for potential energy.
I'll toss this idea up the pole... comments invited.
Hooray (Score:3, Funny)
Infinitely expanding is necessarily non-cyclical? (Score:2)
Oh... and you can't prove anything in science... so they aren't going to release a paper proving dark matter.
Dear Multivac^WSlashdot (Score:2)
How can the net amount of entropy of the universe be massively decreased?
(With apologies to Asimov [rochester.edu].)
Dark Energy doesn't mean Heat Death (Score:2)
This is the way the world ends ... (Score:3, Interesting)
That said, an infinitely expanding (or "open") universe is just as likely to destroy all life as the "big crunch" at the end of a collapsing (or "closed") universe. The open universe eventually winds down as all the energy in the universe become homogenized by the 2nd law of thermodynamics in a fate that is often referred to as "heat death".
If anything, the symmetric fate of a closed universe is usually considered the more hopeful fate of the universe mirroring the more traditional cyclic cosmologies of many cultures. Not only does it allow for a sort of cosmic reincarnation but also provides insight into the origin of our own universe (plus some really interesting theories as to the nature of time).
As I see it, an open universe is going to fuel some interesting debates among proponents of the strong anthropic principle (unless they are also advocates of a mischevious "trickster" creator). At least we can take solace in the possibility that matter-energy lost from our universe is "reborn" through inflation events on the far side of black holes. Otherwise, its all seems to me to be an awfully big waste of space-time
Looking back, looking forward. (Score:5, Insightful)
The universe came into being. At first, there was but one force. As the universe grew larger and colder, aspects of that one force that were hidden became apparent - these are the forces we know of now: gravity, electroweak, strong nuclear.
Consider:
Trillions of years from now, the universe is much larger and colder. Aspects of the four forces we know of now become apparent, creating new forces.
Who is to say that in a google of years, there won't be some lifeform that will look back and say (translating to English) "We aren't sure what happened in the first trillion years, but after that, the 27 forces of nature we know of began to manefest themselves..."
Who is to say that there was not some lifeform living at the first 10e-32 second that was looking forward and saying (translating into English) "One day, seconds from now, all life as we know it will cease, and the universe will be far too cold to support life."
Re:Looking back, looking forward. (Score:4, Informative)
Re:Looking back, looking forward. (Score:3, Insightful)
Interesting... we do actually discover new physics in the domain of the supercool. Perhaps new life might evolve in the form of superconducting structures in the iron corpses of burned-out black dwarfs in the unspeakably distant future, and wonder about the time in the afterglow of the Big Bang in which a mysterious quantity called 'electrical resistance' dominated physics...
The Standard View of Gravity (Score:4, Interesting)
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--
The Real Story (Score:5, Informative)
The basic way at looking at cosmological parameters is this: CMB tells us about the geometry of the universe (Omega_total = Omega_matter + Omega_energy), clustering tells us about the matter content (Omega_matter), and supernovae tell us about the acceleration of the universe (Omega_matter - Omega_energy).
Only supernovae have given us direct evidence that the universe is accelerating.
Dark energy (Score:3, Interesting)
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....
They need to address Halton Arp's observations (Score:4, Interesting)
He's published several books on the subject including Seeing Red: Redshifts, Cosmology and Academic Science [amazon.com] 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 [astroleague.org] some other info about it.
*Evidence* favors many things. (Score:3, Insightful)
Evidence can be used to support anything. To prove it, though, is another thing entirely.
Expanding Dark Energy The Result of Spam (Score:3, Funny)
They hit reply and the rest is history.
Re:It's the midichlorian's fault (Score:2, Funny)
Re:Stephen Hawking... (Score:2)
Yeah, not only did the poster get Hawking's position on this issue wrong, he gave the wrong link to Hawking's page. Here's the real one [mchawking.com]!
GMD
Re:Stephen Hawking... (Score:2)
s/Astrologists/Astronomers
Re:Time to re-write some sci-fi. (Score:3, Informative)
Don't forget your towel =)
"Dark Force" is a stupid name? (Score:4, Funny)