| The End Of The Universe
Posted: 1/3/2008 3:24:47 PM | In the long run, what happens when there is no more reactions producing heat and everything dissipates into space?
Does radioactive decay occur or something else? What is it?
Does dark matter have anything like radioactive decay? | |
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| The End Of The Universe
Posted: 1/3/2008 4:28:58 PM | If something hasn't been radioactive, it doesn't spontaneously become radioactive. A radioactive nucleus is one that has been "excited". If nothing happens to excite a nucleus, there is no way that it will become radioactive on its own.
As far as I know, they (cosmologists, astro-physicists, ...) haven't decided yet whether are universe will fall back on itself, will expand to some maximum size and stay there, or expand forever. ( I think the fall back is more or less ruled out.) But at some point, stars will run out of the easy fuel (hydrogen and helium). So, the things which generate heat won't be generating as much. If things collapse locally due to gravity, nuclear reactions can result if enough mass is present. So, you can make a little more heat locally from that. But "heat death" is that the temperature of everything gets to be about the same, and hence no (net) energy is flowing from one object to another. With no energy flow to exploit, everything more or less grinds to a halt. But that is a LONG way in the future. | |
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| The End Of The Universe
Posted: 1/3/2008 6:06:07 PM |
Are there different elements of dark matter?
Maybe, but probably not in the sense I think you're suggesting. Dark matter isn't a "special" kind of matter. It is unobserved matter. We call it black because their is evidence that it exists, but we can't see it. Much dark matter is suspected to be hydrogen, which contributes much mass to the universe, but can only be observed at a distance when there are stars to show us it's there. Other substances could also be part of this mass. | |
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| The End Of The Universe
Posted: 1/3/2008 10:15:04 PM | | That's all very well except that SOMETHING had to create energy, charge particles, exclude nuclei etc to begin with. Regardless of whether your beliefs on how that happened are rooted in religion, science or Tolkeinism, if it's happened before it stands to reason that whatever it was can happen again. | |
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| The End Of The Universe
Posted: 1/3/2008 11:04:32 PM | > In the long run, what happens when there is no more reactions producing heat and everything dissipates into space?
Assuming the universe expands for an infinite time into the future, the universe 'ends' with a whimper, eventually becoming nothing but a sparse sea of low energy photons (and neutrinos) continually getting lower in energy due to that expansion.
> Does radioactive decay occur or something else? What is it?
Protons and neutrons are thought to eventually decay into other particles: "Protons are observed to be stable and their theoretical minimum half-life is 1×1036 years. Grand unified theories generally predict that proton decay should take place, although experiments so far have only resulted in a lower limit of 1035 years for the proton's lifetime. In other words, proton decay has never been witnessed." (wikipedia)
> Does dark matter have anything like radioactive decay?
Nobody knows anything about dark matter. It's a hypothetical construct and may not actually exist - just like the ether which was once supposed to exist in order to make it possible for EM waves to propagate. | |
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| The End Of The Universe
Posted: 1/4/2008 12:04:26 AM |
That's all very well except that SOMETHING had to create energy, charge particles, exclude nuclei etc to begin with.
Oh really? Says who? You?
And just where does this 'something' come from, hmm?
Regardless of whether your beliefs on how that happened are rooted in religion, science or Tolkeinism, if it's happened before it stands to reason that whatever it was can happen again.
The concept of the universe can be proposed as "Begining/Process/End", like absolutely every other concept we know of. | |
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| The End Of The Universe
Posted: 1/4/2008 8:36:40 PM |
The concept of the universe can be proposed as "Begining/Process/End", like absolutely every other concept we know of.
Oh really? Says who? You?  | |
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| The End Of The Universe
Posted: 1/4/2008 9:39:38 PM | Dark matter isn't a "special" kind of matter. It is unobserved matter. We call it black because their is evidence that it exists, but we can't see it. Much dark matter is suspected to be hydrogen, which contributes much mass to the universe, but can only be observed at a distance when there are stars to show us it's there. Other substances could also be part of this mass.
I know that Dark matter can be said to be unobserved matter. But this is obvious don't you think , since there might be and probably are trillions of other stars and planets and galexies and who knows what else out there. There is an unlimited Universe out there it seems and obviously most of the matter we don't know about and thus we can't see them. I mean there could be trillions of planets out there and same with stars and star remnants which naturally cotain enormous amounts of matter (M.A.C.H.O.S- like White Dwarfs,the elusive Brown Drawfs, Neutron Stars and Black Holes ect), so clearly in that sense, most of the Universe, and the matter in it have not been observed.
But by the way that scientist make such an issue out of Dark Matter, they make it sound like it is really a mystery and exotic, many scientist think that Dark matter is composed of a sea of subatomic particles such as neutrinos.
So I wonder, when scienists mention "dark matter", do they mean just normal matter that we havn't obvserved with our instruments but that is out there and we just havn't seen it...or do they mean something more like it is literally invisable, as in lets say there can be somthing right in front of you that you can't see at all, that to you would appear as empty space and normal air that we breath everyday, but infact there could be something that contains a considerable amount of mass in it (maybe 100 pounds or more), but it just appears invisible to us??
Two different views of "dark matter" , so which one do the scientist lean more towards in their definition and in how they see this as an abstract idea?
This theory of the "end of the universe" comes down to two main theories, the "Big Crunch", and the "Big Expansion".
The "Big Crunch" can only happen if there is more Dark Matter then there is Dark Energy, and in recent years there have been more and more evidence for the expansion of the Universe do to the Redshifts being picked up on distant Galexies as they travel away from us and not only, does it appear that the Universe is not slowing down at all with it's expansion, but it also seems that the Universe is actually accelerating and it is by that process that "Dark Energy" has been brought up as the reason for this rapid expansion.
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| The End Of The Universe
Posted: 1/4/2008 9:50:11 PM | I mean there could be trillions of planets out there and same with stars and star remnants which naturally cotain enormous amounts of matter (M.A.C.H.O.S- like White Dwarfs,the elusive Brown Drawfs, Neutron Stars and Black Holes ect), so clearly in that sense, most of the Universe, and the matter in it have not been observed.
Just for the record...
White dwarfs and neutron stars are NOT "dark matter" because they do emit energy and can be observed directly. White dwarfs still emit residual radiation as it cools off, and neutron stars emit highly-focused beams of radiation at regular intervals due to their spin and magnetic fields (which is why neutron stars are called "pulsars"). Brown dwarves are also sometimes directly observable because many of them have an IR signature, which IR telescopes like Spitzer can pick up. (I think one of the ongoing projects using Spitzer right now is a hunt for brown dwarves).
As far as the common definition of "dark matter" goes, it's the astronomer's term for "missing mass". We can observe gravitational effects exerted by something around distant galaxies, but we can't see what it is. "dark energy" refers to the mysterious force that is accelerating the expansion of the universe, since the universe is not expanding at a constant rate or slowing down due to gravity, but it is actually speeding up.
Unfortunately, we don't know much about those two "dark" things at the moment. I think we might get some more clues when the James Webb Space Telescope finally launches in a few years. | |
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| The End Of The Universe
Posted: 1/4/2008 9:56:37 PM | Just for the record...
White dwarfs and neutron stars are NOT "dark matter" because they do emit energy and can be observed directly.
I know they are not dark matter at their initial an middle stages, but after they loose their energy over billions of years, they eventually loose all their power and light and energy in them, and they go dim and become completely dark/black, so then they become invisable and can be seen as "dark matter".
Brown Drawfs, although by definition radiate right and are v ery much visible, the fact that astronomers and cosmologists can't detect them, suggest that they are a "matter" that is very elusive even though they should be quite easy to find with their size being about the size of Jupiter, and having a mass of atleast 10 times of Juputer, the fact that they can't detect these things, can classify them as "dark" or "Unobserved" matter or just plain "Dark Matter".
Brown dwarves are also sometimes directly observable because many of them have an IR signature, which IR telescopes like Spitzer can pick up. (I think one of the ongoing projects using Spitzer right now is a hunt for brown dwarves).
Actually, my understanding is that Brown Drawfs have yet to be detected without a shred of doubt. Scientist are pretty sure that they exist, because they are what scientist call the "missing link" between large Planets such as Jupiter, and small Red Drawf stars. They fill in the gap (mass wise) between Jupiter-sized planets, and small Red Dwarf Suns.
neutron stars emit highly-focused beams of radiation at regular intervals due to their spin and magnetic fields (which is why neutron stars are called "pulsars").
I understand, but I mean after all that, when the Neutron star comes to the end of it's celestial life, it just goes completely dark, like a white dwarf and any star for that matter eventually does. Black holes obviously naturally are already black. | |
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| The End Of The Universe
Posted: 1/4/2008 10:21:54 PM | Yep, I agree with you that after the white dwarves and neutron stars radiate away all of their residual energy, they do become unobservable by direct means (the only signature left would be their gravitation, plus maybe the planetary nebula around a white dwarf if it hasn't totally dispersed or isn't illuminated by nearby stars). The only thing is, through observations we do know at what rates they radiate their residual energy, and if I remember correctly, the universe isn't old enough (just 15 billion years at the most) for even the oldest white dwarf or neutron star to even come close to exhausting their residual energy at their observed rates of energy radiation. (i.e. it will take a few dozen billion years for a typical neutron star to lose all of its rotational momentum and stop spinning and emitting.)
That's my understanding anyway.. I can be wrong, and I'm always on the lookout for current research data which more often than not turns up unexpected results. :-)
BTW I think the first brown dwarf discovered was confirmed in 1995... Not totally sure though. I think it was confirmed through observations with the Hubble Space Telescope. | |
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| The End Of The Universe
Posted: 1/5/2008 10:37:52 AM | .
I seriously doubt there can be an end to the universe.
If we accept that matter/energy can neither be created nor destroyed then how is the "end" even possible?
The belief that we are in an expanding universe and that is the way the "whole" universe works seems to me sort of strange. (one side of the equation).
If someone approached me with something more reasonable where evolution of the universe took on a look closer to that of the earths carbon cycle, applied that to the universe such that there must be an equal and opposite contraction somewhere else that would certainly be easier for me to accept.
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| The End Of The Universe
Posted: 1/5/2008 10:49:41 AM | The belief that we are in an expanding universe and that is the way the "whole" universe works seems to me sort of strange. (one side of the equation).
Keep in mind that the expanding universe has been confirmed by very simple telescope observations, first noticed by Edwin Hubble back in the 1920s.
When Hubble looked at distant galaxies and looked at the spectra of the light coming from those galaxies, they appeared redder than expected. The redder appearance is due to the doppler effect of the object moving away from you. And this has been true of 99% of all the galaxies observed (the remaining 1% of galaxies that do not have this doppler effect are those in our Local Group such as Andromeda, which our Milky Way is directly interacting with gravitationally and will collide with in about 2 billion years.).
If the vast majority of galaxies we can see in our telescopes have a red shift, that means they are moving away from us. Which means the universe is expanding.
And you can make one more logical deduction from this observation: If the universe is expanding, then at some time in the past everything in the universe must have been a lot smaller, which meant the universe was probably born from a Big Bang explosion. | |
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| The End Of The Universe
Posted: 1/5/2008 10:57:59 AM | .
Right and I understand that. Which is to say that "what we can see" is moving away.
My understanding of nature and t he cosmos however does not allow me to accept that it is a one way street. While it may be expanding on our side of town it is most likely contracting on someone elses side of town simultaneously.
Most everything in nature is "closed" loop.
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| The End Of The Universe
Posted: 1/5/2008 2:52:44 PM | My understanding of nature and t he cosmos however does not allow me to accept that it is a one way street. While it may be expanding on our side of town it is most likely contracting on someone elses side of town simultaneously.
If that's your hypothesis, then you need to design an experiment to test it. Go forth and see if you can find evidence of the existence of "someone else's side of town" and present your observational data.
Speaking on currently available evidence, anything beyond the observable expanding universe is conjecture at this point, of course.
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| The End Of The Universe
Posted: 1/5/2008 3:49:06 PM | | The question I feel is the Universe eternal, when some scientists believe that in the beginning there was nothing | |
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| The End Of The Universe
Posted: 1/5/2008 8:16:49 PM | | I do not believe there is a beginning or an end to the universe. I know the current "Big Bang" theory indicates a beginning and an end. But there are so many holes in the theory it doesn't even seem likely to be true to me anymore. There are other theories that make more sense. In any event, it just doesn't seem logical there is a beginning and or end to the cosmos and over the next couple decades, I think the science community will move towards that thinking. | |
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| The End Of The Universe
Posted: 1/5/2008 8:25:44 PM |
Keep in mind that the expanding universe has been confirmed by very simple telescope observations, first noticed by Edwin Hubble back in the 1920s.
No "center" of the expansion has been observed. And there has been no evidence of an outer "border" to the cosmos either. Sure, we can only observe up to the event horizon (the known universe), but all evidence indicates the cosmos continues on indefinitely over the event horizon.
If the vast majority of galaxies we can see in our telescopes have a red shift, that means they are moving away from us. Which means the universe is expanding.
And you can make one more logical deduction from this observation: If the universe is expanding, then at some time in the past everything in the universe must have been a lot smaller, which meant the universe was probably born from a Big Bang explosion.
The universe "appears" to be expanding. But in order for it to actually be expanding you must ASSUME time is NOT expanding. Where is the evidence that time in linear? Is it logical to assume only 3 dimensions of a 4 dimensional cosmos are expanding? Or is it more logical to assume all 4 dimensions are expanding? Remember, void of any evidence to the contrary it's always more reasonable to assume similicity over complexity. The scientific community has abandoned this "logic" in favor of "faith" when it comes to the Big Bang unfortunately. | |
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| The End Of The Universe
Posted: 1/5/2008 10:06:07 PM | The universe "appears" to be expanding. But in order for it to actually be expanding you must ASSUME time is NOT expanding. Where is the evidence that time in linear? Is it logical to assume only 3 dimensions of a 4 dimensional cosmos are expanding? Or is it more logical to assume all 4 dimensions are expanding? Remember, void of any evidence to the contrary it's always more reasonable to assume similicity over complexity. The scientific community has abandoned this "logic" in favor of "faith" when it comes to the Big Bang unfortunately.
Not sure where you are getting the idea that the scientific community assumes time is "linear". Especially since the further away a galaxy is from the observer here in the Milky Way, the faster it seems to be moving away from us (higher redshift the further the object, appearing to be moving at a significant fraction of c, i.e. relativistic speeds). Relativistic time dilation and compression for the observer and observed is involved here for the very distant objects.
I think a better person to discuss this with would be the folks who ran the HDF and HUDF observations because they can explain the observed relativistic factors better than I can. Contact information here if you wish to follow up with them: http://hubblesite.org/newscenter/archive/releases/2004/07/text/ (scroll to the bottom of the page for the project officers' email and phone numbers.)
Just don't assume that whoever you are talking to are making assumptions you assume they are assuming, LOL. ;-)
No "center" of the expansion has been observed. And there has been no evidence of an outer "border" to the cosmos either. Sure, we can only observe up to the event horizon (the known universe), but all evidence indicates the cosmos continues on indefinitely over the event horizon.
Remember what you said about time not being "linear?" One needs to take into account the relativistic factors of galaxies further away appearing to move faster due to the great distances and speeds involved. If there is an observer in every galaxy, each observer will see the galaxy furthest from him to be moving faster than those galaxies closer to him. In such a situation I'm not sure you can actually observe a "center" of expansion, because the center of expansion will appear to be where the observer is located. Sounds to me like you can observe a center of expansion ONLY if time is "linear" (i.e. non-relativistic).
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| The End Of The Universe
Posted: 1/6/2008 1:38:26 PM | What I meant to say is that the "scale" of time is may not be linear but rather is what is expanding. General relatively assumes a linear scale for time. The Big Bang theory assumes a constant linear scale for space. But what if the scale of all 4 dimensions is what is expanding?? Not the universe itself. It's illogical to assume there is an absolute scale. If there is no absolute scale, how can we assume it remains constant? The evidence around us is enough for us to question this. You can form a theory with far fewer holes than the Big Bang theory if you assume the scale of all dimensions is expanding at an exponential rate.
http://www.estfound.org | |
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| The End Of The Universe
Posted: 1/6/2008 1:56:00 PM | I can't see that expanding time would matter. Expansion is observed in our time frame, whatever time frame that is. No matter how you frame it, expansion in our time frame is expansion. To observe distant galaxies and their red shift, we must receive light from those galaxies. Those photons travel at the speed of light in a vacuum. That speed is constant. If the photons travel in space of varying rates of time, they will still always travel at c for the relevant time frame. The end result is that we won't see a difference. Changing the flow of time won't change the wavelength or speed of light.
Whether or not time is a linear scale shouldn't affect us much. We will perceive it the same because we are immersed in its flow. Double the rate, it will seem the same to us and the rest of the universe. Cut it to 10% and it will seem the same to us and the rest of the universe. | |
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| The End Of The Universe
Posted: 1/7/2008 2:24:39 PM |
If that's your hypothesis, then you need to design an experiment to test it. Go forth and see if you can find evidence of the existence of "someone else's side of town" and present your observational data.
Speaking on currently available evidence, anything beyond the observable expanding universe is conjecture at this point, of course.
Hmm yes that would be about as difficult as those who hold the expanding universe theory to prove they have observed the "whole" universe.
The notion that the extent of the observable universe is known is likewise purely conjecture.
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A thought on time; time is nothing more than a construct that we created to better understand our surroundings.
Nothing more than marks on a ruler at equal intervals.
When mathematicians have to start curving time to make formulas work out, though in the end they may come up with correct numbers, neither have the solved or found the root equations.
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| The End Of The Universe
Posted: 1/7/2008 4:04:08 PM |
Whether or not time is a linear scale shouldn't affect us much. We will perceive it the same because we are immersed in its flow. Double the rate, it will seem the same to us and the rest of the universe. Cut it to 10% and it will seem the same to us and the rest of the universe.
Yes, it will seem the same to us in the moment, but when you start to look back in time, the change of scale is very evident. As you go back in time, the scale appears exponentially smaller from the current scale. This explains why you can only look back 14 billion years or so and it appears there was a Big Bang.
The math works out as well, and it starts to bridge the gap between quantum theory and general relativity. Lots of other questions are answered with this theory too. Just take a look at http://www.estfound.org and see for yourself. Of course there is no solid evidence for this theory yet except for the fact that it fits observation a lot better than the Big Bang. Unfortunately the Big Bang has a lot more history and faith behind it. So it is still the leading theory, leaving these other more realistic non-creationism theories behind... for now. | |
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