A new puzzle that Hubble has found....

Check out this interesting find about the origins of our universe;


http://news.bbc.co.uk/1/hi/sci/tech/3680944.stm

 

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I have a question. Supposedly, the big bang happened rougly 15 Billion years ago, and we are seeing light from galaxies that are about that old. But weren't we in the same place as these galaxies at the time of the big bang? For us to see this light, these galaxies would have had to been 15 Billion light years away, 15 Billion years ago, while science tells us that 15 Billion years ago we were in the same place, which means the young light should have shot passed us long ago.. You could say that because of our speed it took light longer to reach us, thus explaining how old these galaxies look, on the other hand the theory of relativity says the speed of light is not relative to anything traveling less than the speed of light and this would not be the case, right? Anyone care to explain where I went wrong in my reasoning? Thanks.

 

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There's a whole lot of things that could be wrapped up in the answer to this question. But they aren't needed to provide a simple answer.

Imagine a very young Universe maybe a billion years after the Big Bang, when galaxies are just beginning to form. Young galaxy A is half a billion light years away from another young galaxy called the Milky Way.

What happens to the light shining from A to the Milky Way? How long does it take to get here?

The answer is that it depends on how fast the Milky Way is moving away from galaxy A, and could be any length of time at all... half a billion years later, when the light gets to where the Milky Way was, the Milky Way has moved on...


There are actually some things wrong with this answer, but it's close enough to give you a conceptual idea of the picture without digging into the depths of General Relativity (which I'm pretty ignorant on anway).

 

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Ok I just thought the theory of relativity said that light would catch up with us just as fast as if we weren't moving, must've misunderstood what I read.

 

You're right. The theory of Special Relativity says that we will see the light exactly half a billion years after it was emitted.
That's one of the things wrong with the explanation.
(Interestingly, from the other galaxy's frame of reference it does take a long time for the light to catch us, but that's a different story)

This is where the theory of General Relativity comes in.
I'm no expert, so be wary of my explanation here - don't trust it for a second!

My understanding is that General Relativity says that in an expanding Universe (like ours appears to be), the space-time of the Universe between distant objects is growing.
This means that although the light from that galaxy is always approaching us at the speed of light in our reference frame (ie independently of our velocity relative to the other galaxy), the space between us and the light is continually being "stretched", so the light has to go further and further to catch up to us.
This would apply even if we were originally stationary relative to the other galaxy... the expanding universe would pull us apart anyway.

I've said as much as I confidently can (more, actually) so I hope this helps.
I suspect, however, that you're left with a decidely unsatisfied feeling. Good! Learning shouldn't just be about finding the answers.

Pete

 

Has this expansion of space that GR talks of been experimentally proven? I mean, things in my apartment seem to be as close to each other as they've always been.

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As they should be, since the're held in place by local gravity - in accordance with GR.

 

Yea, but has expansion of space been experimentally verified, is there any way to verify it?

 

Look into deep space, and check if what you see matches an expanding space model, I guess.
I guess that there might be other models that could match observations as well, but my impression is that they don't mach as well... I think that the CMBR is particularly hard to predict any other may.

 

The question can be resolved, if you will just throw away the misguided myth of the Big Bang, and accept the Steady State theory proposed by many serious scientists ( I know they are in the minority ) but I firmly beleive that by 2012 they will be in the majorety.
Look at the universe as a giant pot of boyling chicken soup, the chicken noodels are the galaxies moving this way and that way randomely. Some are moving towards us, (Andromeda and the virgin cluster, and some are moving away ) but on the whole there is no expansion. It is based on a wrong interpetation of the Hubble Shift.

Regards APOLO ( amateur astronomer )

 

To James R
I respect your opinion on the sciense of astronomy, you are obviosly a learned person, but you are traped in the B.B. theory. If you are to step outside the box, that comprises the current thought on astronomy, and read, f,ex Fred Hoyle's book "A different Aproach to Astronomy" published 6 month before he died in Aug. 2001 you may possibly develope some doubt about the B B theory. At least enough to make you think. Dont forget ( and many people are not awaere of this) , Mr Hubble published many papers and books in his lifetime. And only one paper in 1929 (his first) did he say that the Hubble Shift predicted that it was an indication of distance and speed. In all susequent paper and books did he say, that his initial postulate was wrong, and he beleive that his observations "only" proved that his observation was an indication of distance, not speed. Unfortunately all the subsequently books published grabed on to that 1929 paper and that is what we find in the school books from 1930 to 2004.

Now as I said before, I respect you a lot and your opinions
on most subjects a lot. So I challence you to do a little research (of whitch I'm sure you are capable) to prove that I'm wrong about Hubble
REGARDS APOLO (Retired civil eng. and amateur astronomer)

 

James.

Thanks for your reply. Yes I'aware that most scientists dont think that the modified Steady State theory proposed by Fred Hoyle, Geoffrey Burbidge and Jayant V.Narlikar is a viable alternative to the B B theory. I guess it depends on a person's personal veiwpoint, and way of looking at theories, and one's sense of logic.
At the amateur astronomy club I belong to, the majority of members defenitely beleive that the S.S. theory makes more sense tnan the B.B. theory.The arguments usualy goes like this "how can anyone beleive in a theory that breaks all the known laws of physics including the law of cause and effect".The S.S. theory does not violate any of these laws.
So we will just have to leave it there, and agree to disagree.
Oh, I should mention that a friend of mine- a profesor at the university of Alberta- told me that many of the students going in to the field of astronomy really dont beleive in the B.B. but are afraid to say so, because they would never get a position, and if they did, they would never advance very far.

Regards APOLO

"

 

More importantly it depends on whether the hypothesis is backed by observation. The Big Bang has observational evidence on its side and the steady state does not.

But it does. The steady state relies on there being no point of creation, the Universe always is and always will be. Given that the Universe is, on the whole, a closed system the steady state violates the 2nd law of thermodynamics more so than the Big Bang. Granted that the Big Bang does not address the question of why creation occurs. It is assumed that this will be answered by a more detailed theory.

Further, the Big Bang theory (not hypothesis) was put together using the known laws of physics, it was worked out backwards as new details became available. It can hardly be said to break the laws it uses. The only contention is the first few seconds. That is because we do not understand the physics of those conditions, see previous comment,

Your professor friend is in the minority I feel. The people I studied cosmology with, and many I've met since, accept the Big bang as the better model based on evidence and nothing else.

Maybe your Professor friend can explain why the Big Bang was almost thrown out when evidence was found against it. Maybe he can then explain the new idea that saved the theory and the evidence that supported this very new prediction. One that Steady State can not answer well.

 

Hum,
>>When they measured the rate of star formation in the image's earliest galaxies, they found it was insufficient to create the levels of radiation needed to produce the intergalactic plasma.
"There is not enough activity to explain the re-ionisation of the Universe. Perhaps there was more action in terms of star formation even earlier in the history of the Universe - that's one possibility. Another exciting possibility is that physics was very different in the early Universe; our understanding of the recipe stars obey when they form is flawed."

But....
According to a research team led by the University of Chicago's Jason Tumlinson.
NASA's Wilkinson Microwave Anistropy Probe (WMAP) looked at the oldest light in the universe left over from the big bang, the cosmic microwave background, and found one such clue in the form of ionised (electrically charged) gas floating between the galaxies. WMAP showed that this intergalactic gas was ionised approximately 200 million years after the big bang.
"<i>Very massive stars</i>, with roughly 200 to 500 times the mass of the sun, and more massive than we see anywhere today, are <i>extremely efficient</i> at producing this ionising radiation."
<b>This implies that the earliest stars were massive enough to cause the ionisation ...</b>

 

I read the 2 previous posts with interest
proven by observation ? It seems to me that every time a new observation is made that does'nt fit in to the B B T someone invent a convoluted explanation to make it fit, even if they have to use a crowbar. Inflation is one example of many.
No one has proved that CMR is something left over from th B B, because it cannot be proved. As a matter of fact in the late 1800s 3 astronomers (I dont have their names handy, but I can look them up if anyone is interested)speculated that there should be a certain minimum background temperature in the universe, and they calculated it be about 3. That is prety darned close to the 2.8 it was actualy found to be when the radio telescope was invented in the sixties.
It really comes down to if we beleive Hubble when he kept saying that his original paper in 1929 was a mistake, and the redshift should NOT be interpeted as a measure of speed, but only of distance. And if it does'nt measure speed there is no expansion. Ergo a static universe infinite in time and space.
The 2. law of thermodinamics has not been proven to aply in the cocmoc on a large scale. Even Brian Greene - the famous scientist with the string theory - admits this grugingly in his book "The Elegant Universe".
If some one can explain to me what caused the creation of a universe ex nihilo - out of nothing - and what caused it to inflate all of a sudden, and what caused inflation to slow down at just the right time, I might take a second look at the BBT. Meanwhile I might take a look at the creation story in the bible, it makes eqaualy as much sense. Meaning no sense.

 

This is only an example of science at work. You can not reasonably expect that a fully functional and descriptive explanation of every aspect of creation can be determined in one go. The original Big Bang theory (note it does not tackle why it happens) predicted a small number of observables. These where later observed.

It is woth noting that the Big Bang theory was almost thrown away when the evidence, and two internal inconsistencies, was piled up aginst it. Inflation was a fix for this. Again, if observation did not support inflation then it (and the Big Bang theory) was in dire trouble. The COBE and WMAP data did support the inflationary model to a high degree. An accuracy of 1 part in 10^6 IIRC.

I am aware of this work but it doesn't cut the mustard. IIRC they calculated a background temperature based on ambient radiation from stars. This model would have fluctuations (anisotropies) where the background varies due to higher concentrations of sources (I.E. Stars etc.) and material in the ISM. It would not be highly isotropic in the same way.

The Big Bang models predicted a background radiation due to expansion that was highly isotropic and a perfect black body spectrum. More importantly it made a number of other predictions that where later found to be correct. For example H/Li ratios and baryon/photon ratios. It is worth noting the Big Bang theory also predicts a second CMBR at around 1.2K. If this was found it would be further evidence for the model. No doubt the nay sayers will run around claiming it is shoe horning data to fit a bad model.

Darn close is not good enough. Revised models put the figure around 2.81k which WMAP/COBE found.

Again, it does not come down to this at all. Einstein was very instrumental in providing 'proofs' that Quantum Mechanics was fatally flawed. Those proofs are now upheld as cornerstones of how QM really works. Just because the originator/famous person disagrees with an idea does not invlaidate it. That is a classical logical fallacy many fall into.

Simply put, Hubble disbelieved expansion because the dominant idea was for a static Universe. Again, a mistake Einstein also made with the cosmological constant. Just because Hubble argued against the interpretation does not make him right.

Since Hubbles day there have been countless observations of galaxies. Only a few in the gravitaionally bound local cluster show blue shifts. Nearly 100% plus/minus 10^-12 all galaxies are redshifted with increasing redshift with distance. Unless you can find an explanation for redshift that does not include velocity the current explanation is the only one.

Then you also have to redefine redshift/doppler shift. Which will at least get you a rebate on speeding tickets by redefining fundamental physics.

That is a different story altogether. The feeling is that the 2nd law of thermodynamics is harder to get around than anything else. The problem is constructing a model of the entropy of the entire universe that is accurate. So far this can not be done.

First off, without meaning to sound sarcastic, you may as well believe that the Universe was created by the Great Green ArkleSiezure then.

Secundus, the Big Bang theory never attempted to explain creation ex nihilo. It can't at present though some ideas have been put forward. Such as colliding branes in higher dimensions. That only pushes the question back to, where did the branes come from?

Any such theory will always suffer from the philospical puzzle of 'why did that happen?' It is not that we have a choice between models based on what we feel sits more comfortably with our preconceptions. The best theory is the one that makes predictions which are later supported by evidence. If evidence contradicts the theory then we start again. The best model to date is the Big Bang, bearing in mind it is tested every time some one makes an observation of intergalactic space.

As to what causes inflation look up 'hawking instanton' and 'false vacuum energy'. The next question would be, so where did that come from. I would refer you to a sophist/philosopher and not a scientist for an answer.

In short, a static Universe feels more wrong to many cosmologists than a dynamic one. Once you accept that the Universe is not unchanging, the rest follows.

 

apolo,
The Hot Big Bang theory really isn't about that first instant of creation - it's about the development of the Universe from a very hot, very dense state. This doesn't break down any laws of physics at all.

There are a plethora of models that attempt to address the early times in which GR is too limited and quantum effects dominate - the Big Bang theory just doesn't go there.

 

thed

Thanks for your post from yesterday. It was well written, and well thought out, and I thank you for taking the time.

I'm aware that COBE and WMAP "apears" to support inflation to a high degree. But a high degree is not certainty. It is true that a large majority beleive in the BBT. But of course it is also true that in Galileo's time, most beleived the earth was the center of the solar system (and the world).
I have read at least 18 qualified scientists -beside the 3 I named in aprevious post- who support a version of the modified S S T.

However let me conclude with the following observation. The B B T has become like a religion. If you are a scientist and do not beleive it, you become excomunicated. The christians beleive in one god. The hindues beleive in many gods (128 and counting). The budists beleive in buda (who is not a god). And I beleive in the S S T because it agrees with my understanding of science, my sense of logic and my common sense.

I will now leave the rest of this thread to others who may wish to carry on with this subject.

Regards APOLO.