Great post, Outpost4! A very nice and concise summary of the many reasons that strongly support the Big Bang theory! I wish I had the time and the will to make such a comprehensive description! :thumbsup:
Why does the Steady State Theory not work?
- Thread starter Luckyflux
- Start date
Then I understand that the Sun should rise tomorrow, but I refuse to believe that it will.
That makes me look stupid too.
I was expecting to accompany his (interesting) comment some relevant real life examples (rather than the contrived example you list) - QM interpretations, say?
True..
But only one of them is correct...
Steady-state may be "diametrically opposite", but it's also wrong.
I have some minor quibbles on some of the more esoteric stuff in cosmology, BB being one of them.
It seems that so much of this stuff is simply untestable (although I think technology might help in the future).
We simply can't test the big bang. We have no idea what a BB-free universe would look like. We can't make superdense matter. We know the universe is expanding, but we can't get back to *what* the original seed was. We can't do it.
It gets worse with Dark Energy. We have no idea what it is. It seems to move objects, but we can't detect it, we can't test for it. The universe is expanding quicker than it should, and it seems to be speeding up. How do we know it's dark energy and not some misunderstanding of the natural forces? Maybe its a constant we don't understand, or something we mismeasured. It could be that something that we think is constant. We have no idea. DE is a postulate, but I'm not sure how much different "Dark Energy causes expansion" would differ from "Zeus causes expansion" -- either way, we're potulating somthing we have no evidence for.
I know such things are probably hard to do tests on, but I wish it was a bit more honest. Scientists have evidence that they think points to an infinate density singularity, that doesn't mean that that's the only possible explanation.
I think it was probably the big bang, but I don't think cosmology is nearly as hard a science as they make it out to be.
It seems that so much of this stuff is simply untestable (although I think technology might help in the future).
We simply can't test the big bang. We have no idea what a BB-free universe would look like. We can't make superdense matter. We know the universe is expanding, but we can't get back to *what* the original seed was. We can't do it.
It gets worse with Dark Energy. We have no idea what it is. It seems to move objects, but we can't detect it, we can't test for it. The universe is expanding quicker than it should, and it seems to be speeding up. How do we know it's dark energy and not some misunderstanding of the natural forces? Maybe its a constant we don't understand, or something we mismeasured. It could be that something that we think is constant. We have no idea. DE is a postulate, but I'm not sure how much different "Dark Energy causes expansion" would differ from "Zeus causes expansion" -- either way, we're potulating somthing we have no evidence for.
I know such things are probably hard to do tests on, but I wish it was a bit more honest. Scientists have evidence that they think points to an infinate density singularity, that doesn't mean that that's the only possible explanation.
I think it was probably the big bang, but I don't think cosmology is nearly as hard a science as they make it out to be.
Balthier, both Luckyflux and you have a point. Our knowledge is nothing. Hell, the term "dark energy" is less than ten years old. And regarding String Theory or M Theory or whatever you want to call it? I think the argument that it's a mathematical model in search of a universe is very valid. There isn't a shred of evidence that String Theory is correct. My bet is we'll all laugh and shake our heads about String Theory in thirty years if not sooner.
I have some trouble with your implication there is an intellectual dishonesty in the way the universe is described in the Standard Model. These are people. They work for years on a theory or an experiment. It is natural for them to want to support and defend it. But these are also scientists. Eventually they come around. Even Einstein had to admit he was wrong to reject quantum theory.
Cosmologists are by their nature skeptics. They know we don't know. I'm old enough to remember reading kid's books saying that the Moon was created from the hole that is the Pacific Ocean...maybe. We really didn't know in the 1960s. It's only since the Apollo missions that we think we've figured out the origin of the Moon. We are in a golden age of astrophysics right now and new theories will come along fast, take hold and then die in favor of the next best new theory.
Cosmology is the psychology of the hard sciences.
I have some trouble with your implication there is an intellectual dishonesty in the way the universe is described in the Standard Model. These are people. They work for years on a theory or an experiment. It is natural for them to want to support and defend it. But these are also scientists. Eventually they come around. Even Einstein had to admit he was wrong to reject quantum theory.
Cosmologists are by their nature skeptics. They know we don't know. I'm old enough to remember reading kid's books saying that the Moon was created from the hole that is the Pacific Ocean...maybe. We really didn't know in the 1960s. It's only since the Apollo missions that we think we've figured out the origin of the Moon. We are in a golden age of astrophysics right now and new theories will come along fast, take hold and then die in favor of the next best new theory.
I took a lot of psych courses in college. I was amazed they get away with calling that a science.scotthm said:
So it's kind of like predicting the weather?
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Cosmology is the psychology of the hard sciences.
It seems to me that it is a lot of confusion of what is "unreproducible" and what is "untestable". The Big Bang is unreproducible, sure, but it's hardly untestable. The observations we make today put strong limits on the possible cosmological hypothesis, because the consequences of the Big Bang (or any particular cosmological theory) are still felt today. Observations points to the Big Bang model being correct. Are they definitive? Not yet. But are they strong, robust and coherent? Yes, they are. Usually, it's enough for them to be accepted as the current paradigm. Following observations could change that, granted, but I do not expect that: the Standard Cosmological Model is perfectible, but I think it is more-or-less correct.
Also, mathematical n-body simulations also give a (admittedly rough) way to reproduce the early status of the universe and describe the evolution of the universe (for example the Garching's Millennium Run I'm working on just now). With the (accelerating!
) increase in computational power, we expect simulations to become better and better in describe earlier epoch of the universe, and thus giving stronger constraints on the correct cosmological model.I have some major quibbles on some of the more esoteric stuff in cosmology, but we are working on that! :thumbsup:
Again, Dark Energy a just catching name for a series of really complex mathematical hypothesis. I can really just begin to understand them, and I've studied them for a few years. For now they are just tentative hypothesis (you can judge that by the sheer number of different explanations!), but with time (and funds!
) we will be able to make observation to distinguish between them and choose the best one.Well, I think that we can't be any more honest than that. We know that many of our hypothesis are just that: working hypothesis, but we try to make the best of what we have got.
Unfortunately, on the way between scientific papers and the lay people, a lot of the subtleties are lost, giving the impression that scientist claim to know it all. But that's the fault of "scientific" journalism, not of scientists themselves. Well, I can testify there are some scientists that are pompous, know-it-all assholes, but that's hardly the point!
Those are fighting words!Outpost4 said:
Cosmology is the psychology of the hard sciences.
Nah, not really. I like you.
Maybe I stretched the truth going for the joke.iguana_tonante said:
Those are fighting words!Outpost4 said:
Cosmology is the psychology of the hard sciences.
For example, cosmologists like you don't believe the problems of the universe stem from my relationship with my mother, although if you'd bothered to ask me... Thanks. I like you, too, Iggy.Nah, not really. I like you.
I'm not suggesting that anyone is being dishonest in cosmology, but it's probably more theoretical than most sciences. In hard physics, you'd perform some maeasurments and try to make the maths fit the masurement. Einstein showed by experiment that the presence of the sun bent light before coming up with the theory.
Cosmology in a lot of cases seems to spin maths that describe the universe. In some cases it seems like they aren't really testable yet. String Theory isn't testable, Dark Matter and Dark Energy are strange physics.
It's an infant science. I'm not sure if its the journalists or the scientists that try to make it sound like we're almost certain what happend.
And hopefully you'll get all the funding you need. I think Cosmology will become more important to people living and working in space.
Cosmology in a lot of cases seems to spin maths that describe the universe. In some cases it seems like they aren't really testable yet. String Theory isn't testable, Dark Matter and Dark Energy are strange physics.
It's an infant science. I'm not sure if its the journalists or the scientists that try to make it sound like we're almost certain what happend.
And hopefully you'll get all the funding you need. I think Cosmology will become more important to people living and working in space.
I am perhaps the farthest thing from an expert on physics as you're likely to find. However, I have some logical issues with conventional big-bang wisdom:
But even that takes the redshift observation at face value. To me, the fact that it's perfectly uniform in all directions casts doubts on this being the result of movement, else the Milky Way would hovering exactly where the Big Bang occured thirteen billion years ago. It doesn't seem to me that it WOULD be uniform in that case; you should be able to turn your telescope in one direction and fnid an absence of Cosmic Background Radiation, and an abundance in another, back towards the source.
This is usually explained by saying that SPACE ITSELF is expanding, but that's little better than positing the existence an unknown repulsive force that does not have to be accounted for.
Which is my other pet complaint. Together with Dark Matter, seems like the scientific version of "a wizard did it."
Not quite correct. For one thing, our distant observations are billions of years old, to the point that we know distant galaxies WERE moving away from us. We can accurately say, based on observations, that the univese WAS expanding at the times in which we observe these objects. In the time it took for the light from a galaxy six billion light years away, its velocity could easily have changed, and the unvierse could no longer be expanding.
But even that takes the redshift observation at face value. To me, the fact that it's perfectly uniform in all directions casts doubts on this being the result of movement, else the Milky Way would hovering exactly where the Big Bang occured thirteen billion years ago. It doesn't seem to me that it WOULD be uniform in that case; you should be able to turn your telescope in one direction and fnid an absence of Cosmic Background Radiation, and an abundance in another, back towards the source.
This is usually explained by saying that SPACE ITSELF is expanding, but that's little better than positing the existence an unknown repulsive force that does not have to be accounted for.
Unless you believe, like I do, that the redshift is inherent in intergalactic distances and not a result of movement.
If I'm not mistaken, there are a number of variable stars that seem to do exactly that. Something to do with energy states moving in and out of equilibrium, I'm not quite sure. I don't suppose enough is known about the interactions of different galaxies to know whether or not they affect each other AT ALL except by gravity; we just haven't been watching long enough to know that, IMO.
Which is my other pet complaint. Together with Dark Matter, seems like the scientific version of "a wizard did it."
there's a big difference between "your beliefs are wrong, and here's why" and "you're NOT ALLOWED TO BELIEVE THAT, because it's wrong." look, i'm a big fan of debating with people and trying to get them to agree with me; but even if someone told me that the sky was green, i'd probably think they were crazy or stupid or had defective vision or were just being willfully difficult, but i wouldn't tell them that they're not free to believe it just because it's obviously false. that's a very important distinction.
Actually we are.
Because the big bang happened _everywhere_. Remember the big bang didn't just create the matter in the universe, it created the universe itself.
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And this is based on what? We haven't observed an expansion of "the unvierse itself," we've observed what appears to be the expansion of objects IN the universe.
The logic behind this doesn't work anyway. For "the universe itself" to have expanded in such a way, then the bounds of "space" would have to be finite. Any object thirteen billion light years away from us would be at the "edge" and would observe a greater abundance of objects in one direction as in the other, and a greater density of background radiation in one direction as another. And even the expansion of "the unvierse itself" would not account for the uniformity of cosmic background radiation unless the universe spent billions of years expanding faster than the speed of light, and the light from the Big Bang is just now reachnig us.
i'm trying to say that science SHOULDN'T be treated like a kind of religion, where the current beliefs are considered as unassailable. i mean, i don't think that religious beliefs should be free from scrutiny either, because while most of them can't be tested they at least have to hold up against the law of non-contradiction. but that doesn't mean that people aren't *allowed* to believe stupid things, from a religious or scientific or political or any other sort of perspective.
I agree that for the time being cosmology is more theoretical than some other science (but not all: think of quantum mechanics!
).That's also why it's so exciting: we are on the final frontier!
No, that's the other way around: the measurements of gravitation lensing near the sun made by Eddington were made after Einstein published the General Relativity, and were considered a confirmation of his theory.
Test of general relativity - grav lensing
Word, my friend. Word.
But that's exactly the point! Measurements that refer to the distant past show that back there the universe was expanding slower than now, while measures made on nearer objects (and thus more referring to the recent past), shows a gradient in acceleration.
Far objects - Near objects - Here
Distant past - Recent Past - Now
Slow - Fast - Faster!
Actually, that's exactly why we think it's an expansion. It's the only solution to an uniform motion observed from every point in the universe (since we can't believe that the Earth is at the centre of the universe!).
(edit: another solution is reddening by interposing medium, see later on that.)
In that case, that's the same as the Dark Energy that raises so much doubt.
That's certainly a fair rebuttal, and it was considered a viable explanation for a long time. However, measurements made some years ago (Srianand 2000) pointed out that the CMB radiation was warmer in the past, and that seems to rule out reddening by an unknown interposing medium.
But we know no force other than gravity that could effect at intergalactic distance: strong and weak nuclear force are range-limited, and electromagnetism is nullified by opposed charges on scale larger than those of molecules. You have to develop a NEW physics to explain that (just like they are doing with Brane Theory and String Theory).
Difference is, we are actually studying the magic!
I'm not sure how that makes sense at all. The way I understand redshift, it works something like the Doppler Effect -- the sound gets lower as the object gets farther away. So if the effect is caused by an object moving away from the viewer (like a car passing on the highway), then the entire doppler effect would have to be wrong.
But another problem is that I can't invision a substance that would allow a redshift or doppler effect occur in some situations but not in others (i.e, Andromeda is supposedly getting closer. If the redshift is the result of a substance, then so is the andromeda's blueshift. But why would an unintelligent natural force make one galaxy shift blue, while others shift red? I don't think that works. A natural force can only act by natural laws -- it can't randomly decide that *this* object will behave different from thousands of others.
Then gravity would be much the same -- positing an attractive force to explain why the planets orbit the sun and objects fall to earth.
I don't think this is anti-scientific, provided that we can come up with a reasonable test to explain it. If redshifting isn't acceptable to you, what would be?
But if redshift can be shown to work like the doppler effect, it is the result of movement. And since we've found the doppler effect to work on all other waves, it seems odd that the visible light spectrum would be the one and only exception to the pattern.
If I'm not mistaken, there are a number of variable stars that seem to do exactly that. Something to do with energy states moving in and out of equilibrium, I'm not quite sure. I don't suppose enough is known about the interactions of different galaxies to know whether or not they affect each other AT ALL except by gravity; we just haven't been watching long enough to know that, IMO.
[quote
Which is my other pet complaint. Together with Dark Matter, seems like the scientific version of "a wizard did it."
[/QUOTE]
I'd have to agree on Dark Matter and Dark Energy. Until we know with precision what the effects are, we can't really tell what we're looking at. I think we're probably misunterstanding the fundemental forces and laws of nature.
I personally find it hard to believe that the universe is made out of mostly undectectable energy and matter. Maybe once we can divert the defense budget to the cosmologists, we'll find an answer.
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