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Author | Topic: The Big Bang and Absolute Zero | |||||||||||||||||||||||||||
teen4christ Member (Idle past 5827 days) Posts: 238 Joined: |
2 writes
quote:I think it's pretty clear by now that it's space that is expanding. quote:You are mistaking what goes on in space as oppose to what space itself is. quote:Space is space. It's simply silly to try to define it in terms of other things. We often run into the same problem with trying to define scientific terms like entropy and such to the general public. People tend to want to define such things in terms of normal everyday things. We can't do that all the time. Space is space. Gravity is gravity. Energy is energy. Entropy is entropy. If you try to define any of those terms in everyday language, you will inevitably end up losing much of its meaning.
quote:Where on Earth did you hear this from? quote:Space is space. It is expanding. The way we define substance is anything that occupies space. To try to define what space is by using the word substance makes no sense. Try to think of it this way. You have an epidermis (skin) layer covering your body. We define body hair as strands of dead protein cells that grows out of the skin. What is skin? You can define it in a lot of way. But it's simply silly to try to define what the skin is in term of body hair. No amount of body hair will ever make up the skin.
quote:We thought wrong. Again, we didn't discover air by defining it with normal everyday language back then. We had to invent a whole new concept of matter state, mainly gaseous state. What is gas? If you want to define what gas is in term of rock and dirt, no amount of explanation will do it justice. quote:Space is very physical. The fact that it is not composed of "normal matter" like we know it or that it cannot be defined using everyday normal language does not negate this fact. Anyway, the point is you can't try to understand what space is in terms of other things just like you can't understand what the color yellow is in terms of other colors like red and black. Red is red. Yellow is yellow. Space is space. Gravity is gravity. A field is a field. A bird is a bird. A reptile is reptile. You don't try to define what a reptile is with words like "rock" and "metal" do you? Why would you want to define space with substance and energy?
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teen4christ Member (Idle past 5827 days) Posts: 238 Joined: |
Percy writes
quote:Are you always an on-topic nazi like this? Without proper understanding of what space-time is or isn't, there is no hope of understanding what the big bang is or implies.
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Rahvin Member Posts: 4046 Joined: Member Rating: 7.4 |
quote: There currently is no proof that is the case.When we speak of the distance between two objects, the distance is figurative. It is not a thing. Of course distance is not an "object." Space is not an "object" per se, either. The definition of matter is "that which has mass and takes up space." If space were composed of matter, we would be saying "space has mass and takes up space." That doesn't make sense. You are the one insisting that space is composed of neutrinos and photons. You are the one making the outlandish claim, so the burden of proof is on you to profide the evidence for your whackjob model.
The nature of what is expanding is not yet clear. Sure it is. Space is expanding. The amount of distance between two given objects discounting any additional forces such as gravity is currently becomong larger without physical motion. That's pretty clear.
Space has properties of energy. Space has properties of the potential to do work? What properties would those be? Please, enlighten us.
Then it has mass. Mass can be describes as that which warps space (the warping of space being gravity). How can you say, essencially, that "space warps space?" That doesn't make sense.
We simply do not have the ability to detect it yet. Then how can you say that it is so? At best that would be an unsupported hypothesis. At worst (and I think this is the case) it's utter BS.
I hear time and again that nothing is actually composed of energy And that's true. Energy is the potential to do work. You can't have something "made" of the potential to do work. Star Trek is wrong - "balls of pure energy" and other such nonsense is the purview of science fiction.
Son Goku and others chant that mantra. It is as figurative as treating space as an expanding thing with no substance. Space has no substance as you or I would envision it. It's counterintuitive because of the way we experience the spacial dimensions. But Son Goku and cavediver are physicists. I'll take what they say regarding physics over your rubbish any day. Honestly, you sould like tesla right now.
We used to thing air was "empty" For space to exist and have no mass it cannot be physical. That does not follow. Nothing is "not physical" Everything is made of something. You seem to be proposing something along the lines of the "aether" model that was discarded in the middle ages.
If black holes can be infinitely dense then "space" can be infinitely lacking density and still be physical. Now you really sound like tesla. You've compeltely stopped making sense.
There is no reason to believe the space between the nucleus of an atom and it's electrons is any different than that between galaxy clusters. It's not, except that the intervening space between galactic clusters is far more likely to have small amounts of matter in between. And of course the shear amount of intervening space.
Mass retards the speed of time. Mass is then an island of "slowed experience". Because mass warps space/time. That has nothing to do with your ridiculous notion that space is "made of neutrinos and photons." Space can contain those and other particles, but it is not made of them. Space is defined as any measurement of the dimensions length, width and height. What's the mass of a cubic meter? The correct answer is "a cubic meter of what?" Space alone has no mass.
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cavediver Member (Idle past 3671 days) Posts: 4129 From: UK Joined: |
Sorry Rhavin, I've been wondering if I could be bothered wading in, but I can't let this pass -
Mass can be describes as that which warps space (the warping of space being gravity) Yes, this is good.
How can you say, essencially, that "space warps space?" That doesn't make sense. Yes it does! I'm afraid to say, but 2BP is correct in saying that space has mass - though not for reasons that he understands. GR is a non-linear theory, and as such space-time curvature is coupled to (generated by) not only conventional ideas of matter and energy, but to itself: curvature generates curvature. This is how we can have non-trivial vacuum (empty of matter) solutions to GR. At the quantum level, we see this as gravitons interacting with gravitons. Gluons do the same - quantum chromodynamics is a non-linear theory. Electromagnetism is linear so photons do not self-interact, directly - which is fortunate as there would be no such thing as 'sight' if they did! So, a volume of curved space will exhibit a measurable mass.
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Rahvin Member Posts: 4046 Joined: Member Rating: 7.4 |
quote: Yes it does! I'm afraid to say, but 2BP is correct in saying that space has mass - though not for reasons that he understands. GR is a non-linear theory, and as such space-time curvature is coupled to (generated by) not only conventional ideas of matter and energy, but to itself: curvature generates curvature. This is how we can have non-trivial vacuum (empty of matter) solutions to GR. At the quantum level, we see this as gravitons interacting with gravitons. Gluons do the same - quantum chromodynamics is a non-linear theory. Electromagnetism is linear so photons do not self-interact, directly - which is fortunate as there would be no such thing as 'sight' if they did! So, a volume of curved space will exhibit a measurable mass. Well, I stand partially corrected. Thank you. Still no "neutrinos and photons" making up space though, right? Please tell me I've at least got that right so I don't feel like I've made myself a complete ass
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Percy Member Posts: 22502 From: New Hampshire Joined: Member Rating: 4.9 |
teen4christ writes: Are you always an on-topic nazi like this? Uh, yes.
Without proper understanding of what space-time is or isn't, there is no hope of understanding what the big bang is or implies. It does come up a heck of a lot, but I'm not sure it makes sense to have every cosmology-related thread take on the task of explaining the nature of space/time. Perhaps people could take up that topic over at What is "the fabric" of space-time?. --Percy
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Lyston Member (Idle past 5853 days) Posts: 64 From: Anon Joined: |
How's THAT for a long reply?
Quite nice, IMHO.
for any set quantity of mass, as you decrease volume, temperature will increase, not decrease.
Dip a balloon in liquid nitrogen. You will notice it shrinks as it gets colder. Dip a balloon in a pot of water and heat it up. The balloon will expand as it gets hotter. I don't know if any of you caught that show on absolute zero that nova aired a while back, but it talked about the first time people turned hydrogen (and helium) into a liquid. It also talked about how they got their ideas off of how someone (forgot his name) turned other gases into liquids. That person exerted great pressure onto a gas (IE decreased its volume) to the point where it liquefied. Also, by liquefied, it actually was colder. It didn't suddenly spring back into a gas when he released the pressure.
Matter doesn't have to "disappear" or be destroyed to reach absolute zero, as I understand it. Neither does the volume need to approach zero I did an experiment on Charles Law. If you extend the sections of the graph (I did three), they all meet at 0 volume, 0 kelvin. En.wiki sums it up the best with (Charles Law):
Therefore, as temperature increases, the volume of the gas increases.
Notice the gas part. If the fact that it is gas screws up everything, let me know. I don't see how it could, however, as every element has the potential to become a gas at a certain temperature. (Especially since everything used and tested with Charles Law becomes a liquid/solid as it goes down the scale.
Theoretically as a gas reaches absolute zero the volume will also reach a point of zero. If you go way back, the Universe was so hot, small, and dense that normal matter the way we recognize it didn't exist - matter took the form of a quark-gluon plasma, basically an incredibly dense soup of particles so hot that they can't even form into neutrons, protons, or electrons. What about Bose-Einstein condensate? (That word took a very, very long time to find, so appreciate it. I hate knowing what it is but not its name...) Roughly, it is a state of matter "a large fraction of the atoms collapse into the lowest quantum state of the external potential, at which point quantum effects become apparent on a macroscopic scale." It is found at impossibly low temperatures, but it has been achieved. As for your definition of the Big Bang, it makes a lot more sense than a little explosive dot, but at the same time it makes less sense. Maybe my thinking is too narrow, but I can't comprehend how, why, or if space is expanding. My thinking is, if you were to go in some zippy little spaceship that could travel faster than the rate of 'expansion', you would never reach an end of space.
We are just experiencing the shape of the Universe as we move through the dimension of time. Can you elaborate on this please? Thanks for the reply.
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Lyston Member (Idle past 5853 days) Posts: 64 From: Anon Joined: |
By "laws of pressure", if you mean PV = nRT, think about it. Volume would not be zero. P would be zero and would give an undefined answer for V.
I mean Charles Law: V1/T1 = V2/T2, the one used to find absolute value in the first place. At least, I was fully capable of finding absolute value with it.
But more importantly, conditions of the universe at this stage cannot be described by the universal gas law because there was no gas to speak of. So when using Charles law, is it automatically ineffective because a experimental substance becomes a liquid or solid? That wouldn't make sense. If it were so, then absolute zero wouldn't be the number we know it as. At the closest scientists have got to absolute zero, NOTHING is in gas form. At the same time, if you were to heat something up to unimaginable temperatures, it would have to be a gas or above that, like the opposite of a Bose-Einstein condensate. But the Big Bang defies laws of physics, and enters something I can't seem to grasp. Here is how I see it: the Big Bang defies the laws that make up the universe, so obviously there is a point where laws don't count.
If you go back a little farther, our normal laws of physics stop working - the mathematical models stop making any sense. This is the period between T=0 and T=10^-43, a tiny fraction of a second, and we call it a singularity: a point where the normal rules no longer apply, and we really don't know much at all. I've seen history programs where they talk about ancient prophesies covering them selves up with vague or weak points. I wouldn't be surprised if this was considered one of them. Meh, as you all can prolly tell, I don't believe in the BB theory, I was merely offering a bit of information to see what kind of feed-back I could get. (Looking through, I see more feedback on what defines "space" than things on BB.) Edited by Lyston, : Didn't finish.
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Lyston Member (Idle past 5853 days) Posts: 64 From: Anon Joined: |
Are you always an on-topic nazi like this? Without proper understanding of what space-time is or isn't, there is no hope of understanding what the big bang is or implies.
I loled. Learn what defines a Nazi, understand that it not a substitute to 'focused', and that Nazi is merely a follower of Hitler, and that MOST Nazis didn't know about all the corrupt and evil things he did. Every military vet of Nazi Germany I know never knew about the Holocaust until after the war. There, that's your off-topic fix of the day. Learn what a Nazi is, then we can discuss space, then we can return on topic, yes?
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Son Goku Inactive Member |
Lyston writes:
Looking at the Big Bang in reverse, matter is being forced into a smaller volume (because there is less volume to go around), which brings with it a huge increase in pressure. This will cause the temperature to go up. Your example above is a constant pressure example. Dip a balloon in liquid nitrogen. You will notice it shrinks as it gets colder. Dip a balloon in a pot of water and heat it up. The balloon will expand as it gets hotter. The mismatch between what you are saying and what Rahvin is saying is that in any given thermodynamics process, you have two independent thermodynamic quantities and the third is expressed as function of the other two. Rahvin is correct in that increasing volume will decrease temperature. Here volume is the controlled quantity and temperature is the result. In your balloon case, you have control over temperature. Basically one is a PV diagram process and the other a TP diagram process. Plot the dependence using the equation PV = T (nR set to 1, in case anybody is wondering). You'll see that you are both right, but you are talking about two completely different situations. The matter at the Big Bang wouldn't have been in a Bose-Einstein condensate as the temperature wasn't right for one to exist. Also a Bose-Einstein condensate would lead to a very different current universe, which we don't observe.
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Chiroptera Inactive Member |
One thing that I will add is that since we have the law of conservation of energy and temperature is a measure of energy, then there are constraints on the temperature. This means that the pressure and the volume are no longer independent quantities, but one will depend on the other. For a process such as this (called an adiabatic process) we have, for an ideal gas:
TVγ = constant where γ is a constant. Of course, the early universe was not an ideal gas, but the idea is the same. Since temperature will depend on the unchaning amount of energy, this means that we really have one independent quantity, which we can choose to be the volume. Then the temperature will depend only on the volume, since the pressure will also be constrained. There is a tragic flaw in our precious Constitution, and I don't know what can be done to fix it. This is it: Only nut cases want to be president. -- Kurt Vonnegut
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bob-bc Junior Member (Idle past 5877 days) Posts: 1 From: Tucson, AZ Joined: |
Respectfully, space, by definition wouldn't be empty. Something moving thru something would lose energy. Hence the red shift.
Speaking of which, which way is this light moving? Something happening 7.5 billion light years ago would have been 7.5 billion years closer to us, hence the light would have passed us back then. Unless......unless the light we see is the light moving from the other side of the object directly away from us, and curved by the mass of the universe 360 degrees. Impossible you say? What other explanation would there be for a uniform cosmic background radiation coming from all directions at once? IMHO Bob
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Rahvin Member Posts: 4046 Joined: Member Rating: 7.4 |
Dip a balloon in liquid nitrogen. You will notice it shrinks as it gets colder. Dip a balloon in a pot of water and heat it up. The balloon will expand as it gets hotter. Son Goku answered this perfectly. Remember, stars initiate fusion because they are compressed by gravity, and the compression raises the temperature until the reaction begins.
What about Bose-Einstein condensate? (That word took a very, very long time to find, so appreciate it. I hate knowing what it is but not its name...) Roughly, it is a state of matter "a large fraction of the atoms collapse into the lowest quantum state of the external potential, at which point quantum effects become apparent on a macroscopic scale." It is found at impossibly low temperatures, but it has been achieved. The Bose-Einstein condensate is crazy-cool, but it has nothing to do with the Big Bang. Frankly, the conditions were just completely different.
As for your definition of the Big Bang, it makes a lot more sense than a little explosive dot, That's good, becasue that isn't a good representation fo teh model.
but at the same time it makes less sense. Maybe my thinking is too narrow, but I can't comprehend how, why, or if space is expanding. Don't worry too much - it's incredibly counterintuitive, and you can't understand it completely without all of the crazy-hard math you only learn in upper-division physics classes. I certainly don't understand the math behind it. I have a good layman's grasp, but I don't know the why of it, either. I'd suggest you ask Son or cavediver.
My thinking is, if you were to go in some zippy little spaceship that could travel faster than the rate of 'expansion', you would never reach an end of spac And as far as I know, that's accurate. See what I mean about counterintuitive? As I understand the model, space is unbounded, and yet space is expanding. It's like an infinite balloon, but the surface is still stretching. But when we model the Big Bang starting with an incredibly hot, dense, and "small" Universe, we wind up simulating a Universe that looks uncannily similar to our own. We were even able to use such modeling to predict the existence of the Cosmic Microwave Background, and even the structure of the CMB looks like what the model predicts.
quote: Can you elaborate on this please? It's another one of those counter-intuitive things. Our experience is tied to time in a single direction in at a single "rate." But time is just another dimension like the spacial ones. We experience time the way we do because the electrochemical reactions in our bodies, including the ones in our brains, only work in the direction of increasing entropy - in other words, the reactions that constitute our thoughts require a sequence of events moving forward in time. This means we can only ever "experience" time forwards. But to an outside observer, someone outside of the Universe and not dependent on the forward passage of time for thoughts and experiences, time would just be another dimension like depth or height. The Universe looks different at different locations in time, just as it does in different spacial locations, and its state in one coordinate is closely tied to its state in neighboring coordinates. Our experience of time is just an artifact of the way our brains work, nothing more. That help at all?
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Rahvin Member Posts: 4046 Joined: Member Rating: 7.4 |
Respectfully, space, by definition wouldn't be empty. Space is not required to contain anything, though. Space can be empty. Most of space, in fact, is empty. The vast majority of the volume taken up by even an atom is empty space, not particles.
Something moving thru something would lose energy. Moving through interstellar space is not like moving through an atmosphere. This again smacks of the aether model which was proven wrong back in the middle ages.
Speaking of which, which way is this light moving? Something happening 7.5 billion light years ago would have been 7.5 billion years closer to us, hence the light would have passed us back then. ...only if the expansion is happening at the speed of light. We've gone over that in a different thread. It takes 7.5 billion years for the light to reach us, but the intervening space has been expanding as well, causing the redshift. The distant object could be stationary, or moving, it doesn't matter. The key is really that the more distant an object is, the greater the redshift. This means that every cubic centimeter of space is expanding uniformly, and the more intervening space between two objects, the "faster" the rate of expansion will appear. Nearby objects have a far lower redshift than distant objects. The expanding space model is so far the most accurate model we have for duplicating the observed evidence.
Unless......unless the light we see is the light moving from the other side of the object directly away from us, and curved by the mass of the universe 360 degrees. As I understand it, the structure of the Cosmic Microwave Background is such that it appears space is not "curved" in that way. Such models have been proposed in the past, but were discarded. You'd have to ask cavediver or Son Goku for a better answer than that - they're the physicists, and they know and understand the mathematics and evidence involved. I only know what the Big Bang model states in layman's terms.
Impossible you say? What other explanation would there be for a uniform cosmic background radiation coming from all directions at once? ...the Big Bang model, which proposes that the Universe was ever hotter, smaller, and more dense as you approach T=0, and was so hot and so dense that the CMB was left as a cosmic "echo" or sorts as the Universe continues to cool down. It's a really good model, you know. It does account for all of the evidence we have accumulated so far. It's the model that predicted the CMB, so obviously the CMB fits the Big Bang model perfectly well.
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lyx2no Member (Idle past 4744 days) Posts: 1277 From: A vast, undifferentiated plane. Joined: |
Pleased to meet you, bob-bc:
What other explanation would there be for a uniform cosmic background radiation coming from all directions at once? How about a theory called the big bang? It’s very popular among people who know the difference between a light year (distance) and a year (time), and who know that when something is “ . curved by the mass of the universe 360 degrees.” It’s heading in the same direction still. There is nothing in the definition of space about stuff. A photon absorbed by an electron can be shot right back out without energy lost. Your (whosever) absorption/emission theory would have a very different signature than what is actually seen. When we see something happen 7.5 billion light years away that is how far away it was when it happened, not how far away it is when we see it. And it is now 11.6 billion light years away. It’s in the making up of that difference that we get a red shift.
And where I can understand why you would be humble in your opinion it’s not coming off that way. I’m not humble at all, but when cavediver or Son Goku (et al.) say something I shut up and listen. And when I eventually do, at long last, come up with a question it won’t be a rhetorical, smarmy, little trap. And like I said, I ain’t humble. I’m not suggesting you should, but if that was my post I’d feel really, really stupid. IMNHO AbE: Gen 2:10 Edited by lyx2no, : I went a bit to far. Edited by lyx2no, : Clicked the edit button accidentally. Kindly ****** I thought that was a beautifully subtle shot at me. I'm kind of disappointed that it's not.
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