Expert: Tom Whiting - 1/16/2011

Question
I am only an armchair amateur physicist, but I have a nagging question that may have been answered early on in the Dark Matter debate.

That is: Couldn't the perception of universal expansion between galaxies be a function of the distance from the earth and be relative to our perception of bodies and their movement, and not an event in real time? That is, similar to how we see the light from ancient primitive galaxies billions of years in the past, and similar to how we see the light from the galaxy in Andromeda 1 million years in the past couldn't we be perceiving MOVEMENT of these bodies relative to their positions in the past and not how they are moving in current real time?

Ancient galaxies are flying further apart, and the galaxy in Andromeda is coming closer to the Milky Way. So the closer we get to earth and the closer the further we move forward in time, the more we would perceive bodies moving closer to us and not away from us. We would therefore see universal EXPANSION of the space between bodies closer to the origins of the big bang and SHRINKAGE of space between bodies closer to us in time and space consistent with the effects of gravity reversing the force of the big bang. We are misinterpreting redshift and blueshift as evidence of movement of galaxies in space in real time and not as artifacts of our observations of these phenomena.

Answer
Hi Scott,
Of course we're seeing the light of the past; that's all we can do. (Nature allows us no choice).
If I'm standing 5 feet from you, you aren't seeing me now... you're seeing me a nanosecond later.
No one can see the present or the future, but assuming the physical and chemical laws hold throughout the Universe, an atom of hydrogen here on Earth is the same as an atom of hydrogen 10 billion light years distant. We already have demonstrated that (by spectral analysis)... and gravity is the same in the solar system as gravity out in the very distant galaxies, that has been demonstrated too. The laws of chemistry and physics are the same throughout the entire Universe. (Otherwise, one could make no accurate predictions about... Anything). But when was the last time your cup of coffee instantly converted to sulfuric acid while you were drinking it? When is the last time you were magically transported from your living room couch to a beach in Miami?  That's what would be happening all the time IF the laws of chemistry and physics were not the same, and Universal throughout the Universe. Strange, unexplained phenomena like that would be occurring all over the place under those circumstances... but we normal people don't see that happening, except for the metaphysics nutsy's out there.

There is absolutely no mis-interpretation of red shift... it is primarily based on the Doppler Effect of change in wavelength (of both sound and light) which has been demonstrated as accurate
ever since it was discovered. You can hear it everyday if you listen for it in traffic, train stations, and racetracks. We even use Doppler Radar in weather stations now).  It has been a standard candle in astronomy and cosmology for over 50 years now. It survived the "tired light" theory and it survived astronomer Fred Hoyle (of the defunct Steady State theory)... and easily survives the Christian Fundamentalist attacks too, as does radioactive decay.
Professional astronomer Fred Hoyle was the toughest attack, more so than the religious zealots, because he knew what he was talking about... but COBE and WMAP proved his theory, the Steady State Universe, was not the correct one.)  Cosmologists answered all his attacks of "Where is your residual radiation from the so-called Big Bang, and where's your minor temperature differences down at the 0.0001 temperature degree level in the background radiation?  As demonstrated by those aforementioned satellites; that's why it took so long from 1965 until the 1990's to develop sensitive enough equipment to measure a one tenth-thousandth of one degree of temperature difference in the 2.73 degree Kelvin background radiation temperature! COBE and more sensitive WMAP demonstrated those small temperature differences to a very high degree of accuracy.   (Any new theory you want to establish, has to be able to account for all that data now, because it's real and it exists, along with the known Universal expansion of space.  If it doesn't, then your rejection of the Big Bang and expansion of the Universe, is meaningless and... without merit, and can be totally dismissed out of hand from a science standpoint.)
(Sorry but the monkey is on YOUR back (pardon the pun) to not only suggest an alternative theory that meets ALL the observed data, but to offer a PROOF that yours is the correct one... that's the way science works now.)

The Andromeda galaxy, us, and about 30 other galaxies, all part of the Local Group (which is a member of the Virgo Supercluster) volume tied together gravitationally, being very nearby, relatively speaking.  So M-31 is close enough that the gravitational force can easily over-ride the Universal Expansion of 71 Km/Second per megaparsec, thus the 2 galaxies are closing and on a near-collision course. For example, the Hubble constant is valued around 71 Km/Second per megaparsec... (a megaparsec is 32.6 million light years), but Andromeda is only some 3 million light years distant, about 1/10th the Hubble constant distance, so the Local Galaxies' gravity can easily override the 1/10th value of the Hubble constant at that very 'short' distance. Thus M-31 is one of the few nearby galaxies blue shifted, and is approaching.
(That's why we see lots of other galaxies in collision throughout the Universe... some are very close to each other to begin with, relative to their size and diameter, and can easily over-ride the Universal expansion value.)
All the other more distant galaxies from us are receding (Edwin Hubble, 1924) and the much more distant ones are receding proportionally to their distance (Edwin Hubble circa 1929).  This information is nearly a century old, and has been checked, and double checked thousands of times. There is no mis-interpretation of Red Shift, just like there is no misinterpretation of T-Rex existing in the Cretaceous period, but not in the following Tertiary period at about 65 million years ago. Spontaneous radioactive decay is just as accurate as red shift.
Recent (1998 I believe) studies of distant Type Ia supernovae have inferred that space is actually accelerating it's expansion. Thus it's now thought that the Universal expansion was slowing by gravity during the first 6 or 7 billion years ABB, but as the effects of gravity grew weaker with increasing distance (See the inverse square law), then a previously unknown factor called dark energy took over and started to accelerate the expansion. And there is no known force to stop the accelerating expansion. (Question today is... is the acceleration, accelerating? If so, then the total lifespan of the Universe will be reduced from trillions of years to perhaps 'only' to 10's of billions of years... still a long time by human standards. And our final demise would almost certainly end with a "Big Rip" as opposed to a heat death. (Because the common little red dwarf stars have estimated lifespans in the several trillion year range).  We have yet to see or find a little red dwarf star move to it's next step in stellar evolution, because not enough time has passed as yet... 14 billion years is just too short of time for a Main Sequence Red Dwarf star to evolve to the next step. (Proxima Centauri, Barnard's Star, Wolf 359, etc)

So, bottom line is... gravity has already HAD it's "shot" of stopping the expansion, but it failed, and was over-ridden some 6 or 7 billion years ago. Dark Energy (whatever that is) is now,
in charge of the accelerating expansion factor.
Another interesting theory, recently developed, involves multi-universes, based on string theory,
but this is currently all highly speculative and theoretical. I have yet to see a "string".
Plus, I'm more into Loop Quantum Gravity as opposed to strings at the quantum level, but honestly I have yet to see a loop of gravity too. This is probably all 22nd century science... but as we explore the smaller and smaller, I personally don't think it will cause any changes to the basic Big Bang and subsequent expansion of space.  And remember, it's not the matter (galaxies) expanding, it's the space they are in, expanding. (There aren't little 'rockets' attached to all the galaxies)! It's the space they exist in, that's expanding.  That's one reason that the sky is dark at night.  (Olber's paradox). That, and red shift, shifting visible starlight down into the infrared and radio portion of the spectrum. So we see a dark, black sky, at night.
Of course, you're free to think whatever you want to think... but I try to keep it as factual and up-to-date as possible.
Hope this helps,
Clear Skies,
tom