New Evidence for Open Universe 231
Observations made by the Hubble telescope have produced evidence that the universe is full of "dark energy", stuff that has mass but does not emit nor block light, and that a disregarded theory first postulated by Einstein about "negative gravity" is actually valid. If true, this would provide firm evidence that the universe will not collapse in a "big crunch" but will expand indefinitely. See the SF Chronicle, New York Times, MSNBC, or CNN for stories (the Chronicle story is the best, IMHO). For background information, you may want to check out the cosmology FAQ or more information about negative gravity. (Update: 04/04 11:03 AM by michael : A couple of people have pointed out that this write-up is inaccurate; I'm not going to try to correct it, but read the comments for more information.)
The REAL model (Score:1)
The sun is an atom, earth "electrons" (we become quarks?)
The galaxy is an atom, the solar system an "electron".
The universe is an atom, the galaxy an "electron"
Oh by the way, light behaves as a particle.
Space contains light.
Therefore space is never empty.
Re:unknown factor solutions (Score:1)
Re:As always... (Score:1)
As for the Casimir effect, what we're really measuring is virtual particle contributions to real physical amplitudes, no different than (say) the higher-order corrections to QED processes like Lamb shift and such.
Re:flat? (Score:1)
Re:Wahoo! (Score:1)
Re:As always... (Score:1)
Of course, "could" is a far cry from "does"... we don't really know what happens.
Re:As always... (Score:1)
With the singularity there is no issue of the density becoming too low. The mass, and thus the radius of the event horizon, simply shrink as particles are radiated through the Hawking process.
Interestingly, the rate of radiation is inversely proportional to the size of the hole, so as it shrinks the process accelerates. Eventually you would get a flash as the last of the mass radiated away very fast. Unfortunately this process does not look like a big bang.
Of course, this is only the prediction of current theory. We have not watched a hole do this, that we know of.
If God created the universe.... (Score:1)
Seriously. What was there before God?
OpenUniverse? (Score:1)
In other related news... (Score:2)
Re:How depressing. (Score:2)
Re:As always... (Score:2)
If you find out the answer in the next one, look me up and let me know
Re:How depressing. (Score:2)
School
Work
Death
Re:How depressing. (Score:2)
If you want to feel less significant, look up at the sky on a clear night.
Most people generally think of what they are looking at as billions of billions of galaxies.
Not true. With the naked eye, you are looking at a few thousand local stars. There are only two galaxies that can be seen with the naked eye (outside of the Milky Way, our own). Andromeda, and Magellenic clouds.
Those billions upon billions of galaxies are not visible to the naked eye, nor even with your average consumer-grade telescope. They're out there. But too far away for you to see.
Re:Ho hum (Score:2)
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Re:As always... (Score:1)
Interesting, don't you think?
As always... (Score:5)
This leaves you with a singularity that exploded for no apparent reason and existed for no apparent reason. Where did it come from? Why did it explode?
How complex do things have to get before "God did it" becomes the best explanation?
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Re:Some additional points. (Score:2)
Re:How depressing. (Score:1)
I wouldn't fret too much. The lights won't be going out all over the universe until next Tuesday at the earliest ;-)
Trollling (Score:1)
INCONCEIVABLE!
Re:As always... (Score:1)
I wouldn't call that "no explanation". It's simply stating the posibility that, perhaps there are some things which fall outside of the scope of what we have narrowly defined "science".
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But haven't they decided it was flat? (Score:1)
Closed = expands up to a certain point, then contracts
Flat = reaches a ceratin size then stops expanding but stays that size forever
Open = expands forever
Re:As always... (Score:1)
I'm no expert at this, but I think that only the state where energy is created from/destroyed to nothing must be unobservable. The actual act of separating the virtual particles and thus making particles out of nothing is not observed.
The observation shows you a stream of particles escaping from the black hole (although nothing should be able to leave from the inside) and the black hole losing mass. No energy or mass is created or destroyed in the observation.
Re:As always... (Score:1)
That gamma radiation comes from matter spiraling in on the black hole. It forms a disc around the black hole, which is hot and has strong magnetic fields. That should be bright by itself, but charged particles getting accelerated in a magnetic field directly emit radiation.
The virtual particle radiation is a function of event horizon surface, the smaller it gets the more energy is lost through radiation. That's why black holes are said to explode at the end of their lives and that's why microscopic black holes that could possibly created in future particle accelerators won't eat the earth.
Re:Ho hum (Score:1)
Oh yes the aboriginal observations of an ancient tribe of desert shepherds... very convincing.
How is it any more valid than, for example, my pet theory that the Universe was created by the sneeze of a gigantic cosmic platypus?
Negative Gravity (Score:1)
Re:How depressing. (Score:1)
Re:time consuming (Score:1)
-David T. C.
Finally!!! (Score:3)
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Re:But haven't they decided it was flat? (Score:2)
Re:How depressing. (Score:2)
"The wisest man who ever lived said it this way:
Now all has been heard; here is the conclusion of the matter: Fear God and keep his commandments, for this is the whole duty of man.
For God will bring every deed into judgment, including every hidden thing, whether it is good or evil."
God loves you and longs for relationship with you. If you want to know more about this, please email me at tom_cooper at bigfoot dot com
One thing that has me wondering is this: if the universe can expand forever, how could there have been a Big Bang in the first place? Are the rules different for this universe than they were for the last one?
Anomaly
Re:As always... (Score:1)
If you want to believe that, get down with your bad self, and see these articles as humanity trying to discover how God did it.
Do not confuse 'Who' and 'How' questions.
Science accepts its mistakes. (Score:1)
This is a lot like you and I writing code-- these folks do their best to find answers that fit in with our (admittedly limited) knowledge of the universe, and they're not going to get it right at first. Unless you write perfect, bug-free code the first time every time, I suggest you cut the scientists some slack. At least they admit they were wrong, fix the theories to fit the new information, and try to improve. Using the willingness of science to admit and attempt to correct its mistakes against it hardly seems fair to me.
I suspect that if someone can find strong scientific evidence for the tale in Genesis, that you will find science quick to accept it. (I can certainly vouch for myself! Prove it, and I will see you in church 28 times a week.) On the other hand, just claiming something is true and being unwilling to budge hardly makes you more right than another person. Just more stubborn.
Re:Origins (Score:2)
It doesn't have a "beginning" or an "end" per se. Those words indicate an existence of a "time before" and a "time after", which there isn't, since time didn't exist until the universe "appeared" and probably won't exist after it either dies from miserable heat death*, or contracts back into the singularity whence it came. Time can only be measured by events. When there are no events, there can be no time. Simple as that.
* Do quantum laws allow for a "heat-dead" universe to truly be "dead"? That is to say there is absolutely zero random pair-generation/destruction going on in the vacuum? Can the energy density == zero? If not then there will always be some aspect of time. It's been a good 6 years since my last modern physics class (which we never got into advanced cosmological stuff like this anyhow...)!!
let's invent things! (Score:1)
I'm inventing upside-down energy with a multiple 'sideways' gravity. SO THERE!
(no, I don't have to prove anything, TAKE THAT!)
Re:Ho hum (Score:1)
Don't be a fool. Everyone knows that Genesis is wrong, and Homer gave the real explanation.
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Some additional points. (Score:5)
First, the existence of a cosmological constant is NOT at all news. Prior observations by both the LBL group doing observations of supernovae type Ia (group page [lbl.gov]) and the BOOMERANG group doing observations of the cosmic microwave background (group page [ucsb.edu]) verified the existence of a cosmological constant several years ago.
Second, as a previous poster has stated, the geometry of the universe is NOT necessarily open.
See especially this informative figure [ucsb.edu] which shows the allowed region of parameter space based on both the SNIa and the BOOMERANG results. As you can easily see, the combined results are consistent with a flat universe with a cosmological constant, but the flat universe is a critical case, and one cannot exclude either an open or closed universe.
Third, what IS new is the detection of an extremely distant SN at redshift z = 1.6. The discovery, made largely by Adam Riess, who is now at the Hubble Space Telescope Institute, was largely serendipitous; it was detected in the Hubble Deep Field, and a number of prior observations allowed Riess to piece together a light curve from which he could infer the intrinsic luminosity. The NEW results are remarkable for two main reasons :
1) Critics have argued that a thin smattering of grey dust in intergalactic space could mimic the effect of a cosmological constant (ie, for a fixed redshift, objects seen are dimmer not due to an acceleration of the expansion of the universe, but instead due to obscuring dust along the line of sight, where the dust must absorb equally well at all frequencies). However, at very high redshift, the relative contribution of matter is higher, and so objects seen are BRIGHTER than what one expects in a freely coasting universe. This is not the trend predicted by the simplest dust model. So the recent evidence is one further advance for the non-zero cosmological constant model.
2) At such high redshifts, clocks appear to be moving faster because of the relative expansion of the universe since then (a photon wavelength is stretched out, but c remains constant, hence the photon frequency is also slowing in time in the universe, as are all clocks). The high redshift SNIa light curve exhibits this general relativistic time effect, and one cannot make sense of the curve without correcting for it.
Re:As always... (Score:2)
In any case, to imagine any events occuring outside the space-time continuum in which we reside - including the formation or destruction of our universe, we must assume that some analogue of time also exists outside. At this point, that is rampant speculation; as are any guesses about the nature of that meta-time or of the meta-processes that take place within.
Re:NOT OPEN!! (Score:2)
That, and I don't like the idea that the fate of the universe depends on whether or not enough black holes are created to constantly redistribute the amount of energy in the universe. This would mean that there is a 'critical black hole density', as of course, white dwarves don't have any antientropic process. Some sense of aesthetics prevents me from believing that the fate of the universe is affected by something as random (and affectable!) as star formation. This is just my indication that there are no real antientropic processes, and black holes do not 'consume' information.
I'm not sure I buy the reasoning on bounded dimensions including time: time is on a different footing than space altogether, and it's fully believable that we live in a universe with three bounded dimensions and one unbounded - I honestly wish I understood more about mixed-signature geometries, because it may be that you could determine this answer from something other than the energy content of the universe.
That's just me, however - I don't like the universe having *any* input parameters at all: after all, energy itself is just a manifestation of the fact that the universe is time-translation symmetric, and if the concept of "time" isn't well defined outside the universe, then the concept of "energy" isn't well defined outside the universe either. Therefore, the fate of our universe must be determinable from some basic property of the physics of the universe in which we live.
I digress: all I meant to point out is that while aesthetics may be a guide in this case, since 3+1 dimensional spacetime has some 'quirky' properties, it may be that 4 bounded dimensions may not be possible considering the symmetries that the 3+1 dim spacetime has to obey.
Re:Einstein's mistake (Score:2)
Yes. I am saying that a sufficiently good experimentalist can always invalidate his own experiment (at least initially), because a good experimentalist knows the weak points and what can be improved. If you don't, you're lying to yourself. A good experimentalist, faced with a result that is way the hell away from expectations, will immediately go back to the experiment and stare at it for hours and come up with a dozen reasons of what might've gone wrong. Then, after all of those have been checked, he'll go to colleagues and ask for assistance. Then, after THEY'VE checked, and confirmed that's what's going on, then they might publish a quiet paper (or more likely, give a talk at a conference) to see if anyone can come up with an intelligent answer that they've missed. Then they'll go to press. That's what I'm talking about. If you can't do that, don't bother going into the field, as you'll end up ruining your reputation. Monopoles in California (it was California, right?) and the Weber bar experiment. Both classic examples of "what the hell??" experiments that should guaranteedly have been checked more thoroughly before going to press.
I think you're talking about an experimentalist in the last stage of the game, where they've run out of every answer other than the "new physics" answer. But still, at least some of those questions will be unanswerable without a new experiment (or should be. Maybe it was a perfectly designed experiment. But every experiment I've seen always has compromises inside it) and that's what I mean.
And no, I'm *definitely* not suggesting that every repeatedly tested experimental effect can be explained away. I'm suggesting that any questionable result in an experiment can be explained away right after performing the experiment. Now, if the results stand after testing as many of the limitations of the experiment as you can think of, then it's real. But no experimentalist in his right mind would ever believe a bizarre result right away.
Let me put it another way. I'm working on an experiment right now that is designed to look at high energy cosmic rays. We have a guess at what their flux should be. If it's orders of magnitude above that, I can immediately give a dozen things to check. Without hesitation - those are mainly instrument failure things, however. If everything seems to be working, I'll go out and check things myself manually. And if everything still seems to be working, I'll run another experiment to check to see if I can confirm my results. Then, if everything's still wacko, I'll ask colleagues for help.
I'm confused, actually, as you seem to be supporting my point - you admit that a good experimentalist will be able to think of more problems with the experiment. That's what I'm trying to say - that a good experimentalist can explain a bizarre result without automatically resorting to new physics, and then in the same breath suggest an experiment to check that problem. His explanation might be totally wrong - maybe the new physics is there - but he'll always be able to come up with something that should be tested first. Compare this to the amount of time it took experimentalists to believe the Solar Neutrino Problem. It took years before anyone believed that, and experimenters were always saying "maybe there's a problem, but we need more statistics" (the cheapest out, but still an out). This is taking far less time - maybe a year - and I just don't buy it.
As for the semantics argument, that's my personal preference, because repetition is what makes things true in people's heads, not truth - and even scientists fall prey to this. You hear something over and over, and it becomes true. If you hear "there is now significant evidence for a cosmological constant", you begin to believe there's a cosmological constant. If you hear "there is now significant evidence suggesting that our understanding of the expansion of the universe is incorrect" you begin to believe that there's a problem in our current understanding.
Re:Einstein's mistake (Score:2)
You're using "invalidate" a little too strongly - I didn't say he would be able to invalidate it - I said he would be able to come up with reasons that would invalidate it. Whether or not any of those reasons pan out to be true is another question.
As for whether or not the presence of a cosmological constant is bizarre, it is bizarre. It's not what we've seen on a smaller scale, though granted our evidence on a smaller scale was much weaker. It's not what was expected - it implies significantly new physics.
As for the final comment, that's just plain wrong - flat out. The flaws in an experiment don't widen error bars - error bars come mainly from statistical considerations and uncertainties in known quantities. They provide a measure of precision, not a measure of accuracy. Going back to the cosmic ray example, for instance, those experiments were way off - but they had great precision. Their error bars were extremely tiny - it just happened that their experiments weren't measuring the right thing, though they didn't know it right at the time (they guessed it afterwards). Depending on the flaw in the experiment, it could be fatal - there are plenty, honestly plenty of those.
Considering the astro data, I know one group was using SN 1a's, which, when you look at the data, are not wonderfully consistent. In fact, there are several astronomers who are beginning to say we don't really know what SN 1a's are (conventional knowledge says that they're white dwarves that exceeded the Chandra limit). Several possibilities jump to mind, including evolutionary concerns and not understanding the physics quite right. These can all be checked, and in the few papers I've read, I haven't seen enough checking to convince me. Again, that could be just me - I'm notoriously hard to convince.
So maybe what I am suggesting is that the teams actually look and see what would have to be true in order for lambda=0 to be within error bounds. Is this bad science, since you're shooting for a specific value? Not really - it's a sanity check. You're just making sure that what you're saying is *guaranteedly* true, and if you have a detractor - someone who insists lambda=0, for instance - you can tell them "well, if lambda=0, then such and such would have to be true."
Weber's measurement of gravitational waves wasn't within two sigma of zero either. I personally don't think that the mass of a few thousand stars is being turned into gravitational waves at the center of the galaxy, though.
Re:Einstein's mistake (Score:2)
I don't agree with your first argument - it's very weak, considering that GR is not a QFT. There's no reason to believe that the vacuum has anything but zero energy, and Mach's principle makes you want to believe that it is zero (Einstein was quite distressed to find out that an empty (Friedmann) universe was a solvable solution of the equations) since in this case you don't have a global matter field to define any of the physical parameters such as mass, etc, and you're essentially defining them in this case via an external field, which is exactly what Mach's principle tries to avoid.
In some sense, you expect the GR limit to have a zero vacuum, since GR should be a 'smoothed over' limit of whatever a QFT of gravity is, if one exists - in some sense, you expect quantum fluctuations to not strongly affect the GR limit (although it very well might). This argument is weak, granted, but GR deals with stress-energy density, not with the gravity of spacetime itself, which is a distinctly quantum process. My gut reaction is still that using vacuum energy to justify a cosmological constant isn't proper, as you're stretching the bounds of where GR is valid.
The second argument is perfectly valid - kindof. The whole idea of "it's going through several phase transitions, so it should be absolutely huge!" is weak, especially with the whole idea of renormalizability. I have little doubt that a final QFT of gravity (again: if there is one) will have an infinite bare cosmological constant.
To be honest, I don't know. My instinct re: the cosmological constant is the same as it is re: dark matter. I don't think we understand gravity at these scales - I really don't. Galaxies look like they have too much mass, galaxy clusters look like they have even more excess mass, all makes me wonder whether or not it's a scaling effect rather than a 'missing mass' effect. With the cosmological constant, it could be the same sort of thing. Again, I could be wrong, but I've always tended towards "the universe is simple" rather than "the universe is bizarre".
Re:Einstein's mistake (Score:3)
Anyway, take something from my field: in the 80s and 90s, a bunch of experiments all seemed to confirm that the positron fraction in cosmic rays increased at high energies. This made no sense - and fundamentally you don't want to believe it at all. But they all confirmed it, until the next class of experiments came along and showed "oh, wait, you didn't have good enough rejection."
The fact is that in a good experiment, they should've immediately guessed "um, we might not have good enough rejection" and in fact, some of them did suggest that, and that's what led to the better experiments. It might've been that what they saw was real, and their concerns were baseless, but they came up with the concerns, which is the important part.
I agree that the fact that several groups got consistent answers is suggestive, but far space astrophysics relies on far too many assumptions to suggest redefining physics on a small scale until you get a huge swath of data to back it up. Everyone nowadays seems to be hinting in every talk and paper that I read that "evidence is mounting for a cosmological constant": no. Evidence is mounting for a systematic problem in our data regarding the expansion of the universe. The fact that it MAY be explained by a cosmological constant is unimportant. The cosmological constant is a 'fudge factor' in these cases: you can't disprove it because you can fit it to the data. The fact that you can fit it to all the data just says that the experiments are all measuring the same thing precisely - not necessarily accurately.
Re:Einstein's mistake (Score:4)
Historically it was set to zero because it doesn't look pretty in the equations, but there's no reason it should be zero, and in fact, current astronomical observations say that it's probably not zero.
Of course, I'll state my opinion flat out and say that I think the astronomical observations are flawed in the first place, for many fundamental reasons (especially the supernova observations. Trust me. Supernovae are anything *but* reliable observations). I've seen too much duplicity in reporting of astronomical data (see also the Hubble Constant war) to believe anything 'surprising' like this.
It's possible, but the researchers IMHO are trusting their own data too much to suggest something like this. Start from the assumption that the cosmological constant is zero, then try to see if there's anything in your data that would explain the problem OTHER than a cosmological constant. If you can't find anything, you're a bad scientist - talk to some other ones and get some ideas. Check those ideas, check your instruments, run the experiment again. Repeat. Only when you've exhausted everything you can think of can you say "well... we might want to consider a cosmological constant."
The "bad scientist" comment up there implied that a good scientist can always come up with a problem in his/her experiment that will cause a systematic error, not that a cosmological constant is inherently bad.
I don't know. IMHO they haven't done enough checking yet to convince me. Supernova data doesn't convince me - they're way too variable, and they are NOT standard candles, regardless of what anyone tells you.
Re:Open universe ? (Score:1)
Re:As always... (Score:2)
Infinitely complex, for no explanation to be the best explanation.
Re:Open universe ? (Score:3)
A few corrections. . . (Score:3)
Secondly, dark energy does _not_ have mass (you're probably thinking of dark matter). Dark Energy is thought to be (by some) the vaccuum energy density of the universe. At the current time, it appears that dark energy is accelerating the outward motion of the universe. This, in fact, is what the supernova observations are showing: given our expansion rate now, we would expect the supernova to be moving away from us more quickly than the actual motion we observe. This suggests that the universe was expanding more slowly in the past than it is now; that is, the universe is accelerating in its expansion.
Because it adds to the overall energy density of the universe, however, it is thought to suggest that it makes the universe flat, cosmologically speaking.
Re:How depressing. (Score:2)
Stalker Deity (Was: Re:How depressing) (Score:2)
You don't have to put up with that kind of harassment. Tell the deity firmly and clearly that you are not interested in a relationship and to cease the unwanted contact.
If She/He/They/It still does not stop the harassment, a court injunction may be the next step....
8^)
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Re:How depressing. (Score:2)
Well, there is at least one that has life. Although possibly not intelligent life.
Re:the universe is not code (Score:2)
No because the universe isn't code
Well, we'll just have to reverse engineer it then.
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Astronomy Picture of the day (Score:5)
Today's Astronomy Picture of the day is all about this, too. It's got a bunch of links at the bottom for people wanting to read more.
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Cosmological constant does not mean "open" univers (Score:2)
Here is a link to a good website about it. [colorado.edu] It is a bit technical, but just look at the first graph. It's well labeled.
SW
The best research I have seen on using supernovae to determine structure of the universe, suggested a "flat" universe that expanded forever due to the cosmoligical constant.
Einstein's mistake (Score:2)
Info about it here. [colorado.edu]
SW
42 (Score:2)
After skimming through The Elegant Universe I became a subscriber to the theory that there are multiple 'universes', so I don't see ours as a singularity, but rather an offspring of any one of millions of other 'universes'...
While that may answer you on one level, you could then ask where the MegaMultiverse came from. Can't help you there. But if God had anything to do with it, I think s/he was on some good blotter at the time.
"Smear'd with gumms of glutenous heat, I touch..." - Comus, John Milton
Re:Origins (Score:2)
I don't buy that. Time is meta-physical. It's existance doesn't depend on the physical.
Sorry, trademarked by SGI (Score:4)
what's really expanding (Score:2)
"(Update: 04/04 11:03 AM by michael: A couple of people have pointed out that this write-up is inaccurate; I'm not going to try to correct it, but read the comments for more information"
Apparently the only thing really expanding forever is Slashdot's ambivalence toward accuracy.
Re:How depressing. (Score:2)
Re:How depressing. (Score:4)
If you really need a purpose, here's one: to provide us with a challenge. If the Universe continues to expand indefinitely, there will be a time when the average density of the Universe is low enough that the formation of news stars becomes unlikely, and the fuel for those stars will begin to be burned up. Survival of the human race will be almost impossible in those conditions. The fight to survive will be the last remaining challenge for a race that will have had more than enough time to uncover a set of physical laws that describe the Universe. We'll need something to do.
Re:As always... (Score:5)
> for no apparent reason and existed for no
> apparent reason.
I can't tell you if it had a reason for existance, but it may be possible to explain why a singluarity exploded. (That whole "where did it come from" question cannot be answered by science: a singularity destroys almost all information about what it was made of. All you can possibly know about what a black hole as absorbed are the total mass, and net charge and angular momentum of what it swallowed. You need the "God did it" method if you demand an answer to that question.)
Stephen Hawking has shown that the particle-antiparticle pairs that are perpetually being created in all of space (according to the current models) can provide a mechanism for a black hole to lose mass and energy. To explain how, we first must relax the conservation of energy by incorporating the results of quantum mechanics.
In high school, you were taught that energy can neither be created nor destroyed, only transformed. Well, this is mostly true. Conservation of energy can be violated, provided that violation can never be observed. The Heisenberg Uncertainty Principle of quantum mechanics puts limits on our observations. (Our uncertainty in the energy of a particle, multiplied by our uncertainty in the time we spend measuring it must be no smaller than an amazingly small number, Plank's constant h divided by 4pi.) The Universe can violate energy conservation, provided that excess energy is gone so fast it cannot be observed.
The Universe, therefore, is able to conjure up a particle and its antiparticle anytime, anywhere. The creation of these particles is referred to as vaccum fluctuations. Anyway, these particles can be produced near a black hole.
What happens if one of these particles falls into the black hole, while the other has enough energy to escape? Well, if you do the math, you find that in some cases, the particle that escaped can survive indefinitely; it can behave exactly as if it were a real particle.
What effect does this have on the black hole? The net effect is a loss of energy. Because of mass energy equivalence, this corresponds to a loss of mass. In effect, the particle that escaped is behaving as though it had escpaed the black hole. If this happens often enough, a black hole can reach a point where it no longer meets the requirements of mass and density to be a black hole.
What happens then? Well, nobody really knows. There are a lot of theories, including a Big-Bang type explosion. The one point I feel I should note is that, if this were a Big Bang sort of situation, then there would be matter in the Universe outside the singularity before it exploded. I'm still not sure how much matter this would be. I also don't know what kind of timescales it requires; if it's fast enough, it may appear as though it were a single explosion.
This may not be the answer you're looking for, but I hope I convinced you that answers are possible when you're asking what triggered the Big Bang.
Re:As always... (Score:2)
Note that I'm not claiming to have just invalidated an entire branch of modern physics, I'd just like someone to explain to me how I'm wrong...preferably in terms someone with only one semester of college physics can understand. ;)
Re:A few corrections. . . (Score:2)
However, if there is enough negative ("dark") energy in the universe, which emits a repulsive force (that INCREASES, or accelerates over distance, which is opposite of the gravitational force, which decreases over distance - I believe that's what Einstein was getting at with the cosmological constant), than the universe 's expansion is accelerating, which in my mind would imply an open universe. I'm not sure how one could have a universe that has accelerating expansion, yet remain closed or flat. I apologize if any of the above is incorrect, I haven't taken a physics class in a long time
Yes, God did "do it" (Score:2)
My conclusion, is that some (many) supreme beings, with knowledge far in advance of ours and power far in advance of ours are responsible for everything we see. They created or at least organized our planet, and seeded it with life. Call them Gods or are creators if you like, but in my opinion our universe and especially our world is to "perfect" to be the result of some random explosion of a singularity.
Nathaniel P. Wilkerson
Domain Names for $13
The Heechee knew this... (Score:2)
P*o*l (Score:2)
big bangs (Score:2)
Maybe the negative energy that forces space apart is a mechanism that makes room for big bangs.
I'm really confused ... (Score:2)
Today it's going to end as freezing desolation of dead stars ...
I never seem to get the right clothes for the ocasion!
Re:Ho hum (Score:2)
Scientific hypotheses are based upon the evidence available at the time. Sometimes there will be different interpretations of the same evidence (competing theories) and it is then up to scientists to devise experiments to try to figure out which interpretation is correct.
As new evidence comes along the theories evolve to reflect this. But that doesn't mean all the old theories were wrong, maybe they just described a particular subset of something, and they needed to be expanded for a more general case.
A good example of this is Newton's Laws of motion, which were superceeded by Einstein's theories of relativity. It doesn't mean that Newton was wrong, just that his theories were a very very good approximation for objects travelling at 'everyday' speeds. In Newton's time they didn't have any way of observing objects travelling at relativistic speeds, as the fastest things around were cannon balls !
Of course you could argue that since Newton and Einstein are in 'disagreement', they are obviously both wrong, and of course God moves everything around by hand.
Open universe ? (Score:5)
Good read elsewhere (Score:2)
flat? (Score:2)
While the evidence does suggest that the universe is flat, when you plug in all the numbers, omega (a nifty number involving lots of fun constants and the total mass/energy of the univers), which should be exactly, precisely, not even a teeny weeny bit off of 1 if the universe is, in fact flat, comes out to .3. Well, if the universe isn't flat, calculation of omega becomes a function of time, so by now (assuming we know the age of the universe reasonably well) omega would be dramatically different than it was at the time of the big bang. (Thus the need for not even a teeny weeny bit of being off of 1). if it was just a teeny weeny bit larger than one at the big bang, it would be huge by now, a teeny weeny bit smaller, and omega would be almost 0. the problem is, this is an energy/time calculation, which brings Heisenburg uncertainty into the picture. so, given the lower end of what "1" means taking uncertainty into account, you get .3 for the current value.
So, according to astronomers, .3 = 1.
To Crunch, or not to Crunch (Score:2)
The point in all this is that the density could be anything it could be 300 g/cm^3 or 10^-100 g/cm^3, but it happens to fall very close to the value needed for a flat universe. And with all the possibilities out there, having a flat universe would be like balancing a pencil on its tip. Since, when we check the numbers, it seems like the pencil wobbles a bit(doesn't perfectly stand on its tip, but doesn't fall into open or closed territory very much), it suggests that we do live in a very finely tuned universe.
I can deal with flat though. Its unique. Its got character. If we ever got into a fight with another universe, flat would kick ass!
Re:How depressing. (Score:2)
I like the fact that we're not special, it doesn't give us any pressure to get something accomplished here.
Re:As always... (Score:2)
I was under the impression that, if a black hole were to shrink below the size necessary to call it such, then it would explode merely in a large outpouring of gamma rays, not necessarily another Big Bang. This gamma ray explosion would be, in an open universe, the only energy source at the far ends of time, due to the evaporation of (for the most part) all matter.
Re:Einstein's mistake (Score:5)
It was a psuedo-mistake. It was thrown in because it *can* exist.
It was not a mistake to include it, not even a pseudo-mistake. At least in hindsight :-) And I don't mean from an observational viewpoint; from a fundamental theoretical viewpoint, you EXPECT there to be a cosmological constant term. Here are just two reasons:
The problem since the seventies has not been to explain why the cosmological constant is not zero (since you wouldn't naively expect it to be), but why it is so CLOSE to zero; that is, why does the universe have some approximate symmetry that keeps the cosmological constant so small, despite what would otherwise be its natural inclination to be large.
Re:NOT OPEN!! (Score:2)
We, in this universe don't see any difference, as our velocity decreases in synchronicity with this universe.
This is the same paradox as event horizon in black holes : you fall in for eternity, here we grow up slowly, for eternity.
Dark energy != Dark Matter (Score:4)
Your dark energy explaination is actually the definition of "Dark Matter". Dark energy is the repulsive force in space that accelerates the already spreading galaxies.
Another theory that supports this "Dark Energy" is the theory of a second sun Nemesis [space.com]
Quality Journalism (Score:2)
> of people have pointed out that this
> write-up is inaccurate; I'm not going to
> try to correct it, but read the comments
> for more information.)
That's what I love about Slashdot journalism. No time is wasted correcting innacuracies. "We're on internet time -- we can't bother." The truth is, there is no immediate benefit from checking the facts before doing a writeup, so *why* bother? The hoardes of people will still come, and the advertisers will still shell out the bucks.
From now on, my news comes from moreover.com -- or (tongue-in-cheek) better yet, the slashdot story generator: http://bbspot.com/toys/slashtitle/
Re:As always... (Score:4)
"... existed for no apparent reason .... 'God did it' becomes the best explanation?
Sigh, I should know pointing out the obvious will accomplish little, but "God did it" does not solve the problem you pose. "God did it" does not explain why something exists for no apparent reason, since then you have God existing for no apparent reason.
Science is finding out the reasons. Be patient.
Pictures and stuff about the topic ... (Score:3)
Blast from the Past: Farthest Supernova Ever Seen Sheds Light on Dark Universe [stsci.edu]
... and some more information, why this should tell us, that the universe is expanding faster.
Whew (Score:3)
After looking at the FAQ (Score:2)
;-)
While this is important in terms of the field, as far as day to day life goes, it is not very important. After all, we have billions and billions of years before the wrap party.
Other areas of research, like the search for planets are slightly more relevant. I want to know if we have neighbors, and if we have to worry about them
The rest is somewhat abstract for my taste.
Check out the Vinny the Vampire [eplugz.com] comic strip
Cosmological constant (Score:4)
The cosmological constant, which provides a repulsion on the cosmological scale, was famously declared by Einstein to be the biggest mistake of his life. However, it has been known for many decades now that the it is a very valid part of the theory - it's not so much a fudge factor as a constant of integration.
Scientists discover Universe is just like women (Score:2)
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Re:Ho hum (Score:2)
Re:As always... (Score:2)
How exactly is that an explanation? Because the next logical question is, What created God?
Re:As always... (Score:2)
Next time, skip the course in mathematics, and take a course in pure logic instead... might be better off.
your "+2 Insightful" question is revealed as the typical, tired, pseudophilosophic
Ummm, it wasn't +2 Insightful, it was just +2. That's because my karma's at 50. So sorry!
Bring on the dark matter (Score:2)
You know what they say: Once you go dark matter, you'll never go back. [ridiculopathy.com]
Re:Ho hum (Score:2)
Isn't this precisely the point of science and it's everlasting quest to prove educated guesses wrong? And a theory is just that, an educated guess, or a hypothesis. Science would be pretty pathetic is we didn't practice this way, the world would still be flat, the earth the center of the universe, ......
NOT OPEN!! (Score:5)
A common misconception, left over from decades of cosmology textbooks which implicitly assumed a zero cosmological constant (equivalently, no dark energy). These textbooks all make the equation that closed geometry = universe recollapses, open geometry = universe expands forever, flat geometry = borderline case.
In fact, if you have a cosmological constant (or dark energy), you can have a closed univere which expands at an accelerating rate.
The best evidence about the geometry of the universe currently comes from cosmic microwave background observations, which suggests that the geometry is *flat*. The supernova evidence suggests that the expansion of the universe is accelerating.
It is a mistake to state that an eternal expansion, or an accelerating expansion, is an "open" universe.
-Rob
Re:As always... (Score:2)
While I find current cosmological theories extremely fascinating, I think making sweeping generalizations at this juncture is really premature. We can only observe a tiny corner of the Universe, and we have only observed a tiny slice of time, though that slice does expand backwards into time through distance. I am of the opinion that our current theories on how the universe works, as brilliant and revealing as they are, will only be the cornerstone for a further generation of theories which we cannot even imagine at this point. What we define as the observable universe may change in one hundred years, in ways that we cannot imagine at this point. That by itself would void almost all current cosmology.
Origins (Score:2)
also 20 new planets discovered (Score:3)
Two British astronomers have counted up to 20 "free floating" planets, drifting in the constellation of Orion. They told the National Astronomy Meeting in Cambridge yesterday that they had identified the "signature" of water vapour in the infrared spectrum of faint points of light in the Orion nebula. This is a vast cloud of gas and dust 1,300 light years from Earth, but visible as the middle "star" in the sword of the constellation of Orion.
Read on [guardianunlimited.co.uk]
How depressing. (Score:4)
In fact, this really means that I doubt what the scientists say on this matter very much. Everything else in nature has a greater purpose and direction, a manifest destiny if you will, whether it be evolution or consciousness or even life itself. Scientists have always prided them on showing the point of life since the days of Euclid, through Newton (who was a very spiritual man) and onwards.
The entire body of science points towards there being a directional purpose to life. This discovery flies in the face of everything we have learned, and I for one am sceptical. Not until they show the higher purpose (multiuniverses?) will I be convinced of this.
You know exactly what to do-
Your kiss, your fingers on my thigh-
Re:NOT OPEN!! (Score:2)
Yes, the term "open" is overloaded... I think the consensus is that the Universe is "geometrically closed" -- that is, it is like the surface of a 4-sphere: a straight line extended in any one direction will return to its starting point.
This would seem to jibe especially well with string theory, where the compact dimensions are "circular" in the same fashion. I would be very surprised if the extended dimensions were not also circular.
The argument seems to be whether the Universe is "open" from a temporal perspective: that is, a 4-sphere can continue expanding forever ("open"), or can collapse on itself ("closed").
Personally, I'm rooting for "closed", for two main reasons:
However, there's a theory that in regions of very empty space, new Universes could "bud" off of our own, so maybe heat death isn't death after all...
Re:As always... (Score:2)
Headlines: Open Universe (Score:2)
Thier copyright must be protected.
The One,
The Only,
--The Kid
Re:unknown factor solutions (Score:2)