Expert: James Gort - 2/27/2007

Question
I read today that the Hubble constant is supposed to give us the speed that galaxies recede from each other.  Supposedly the Hubble Telescope found that the constant is 72 km/s/Mpc.  However when I calculated the speed that the furthest galaxies are receding from us I got the impossible answer of approximately three times the speed of light!  Maybe the Big Bang Theory has to be reformulated as you implied.  Am I still thinking in everyday familiar terms?
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
If the Universe is fifteen billion years old and the furthest stars are fifteen billion light years away then how did the stars get there that fast?  Did the universe really expand at one half the speed of light?  How fast is it expanding today?
-----Answer-----
Hi Brian,

I think the confusion stems from the familiar terms of "age" and "expanding".  With the universe, you have to think about those terms differently.

People often speak of a "Big Bang" that occurred sometime in the past.  "The past" implies that we can actually measure time all the way to the event.  And a "bang" implies an explosion of something into something.  Like a stick of dynamite exploding into the air around it.  In that case, the explosion is "somewhere" and we can point and look at it.  Even after it occurs, there's smoke in the direction of the explosion.

Well, the Big Bang (if it actually occurred - there is NOT consensus that it did!) was NOT an explosion or even an "event in time".  It was, in fact, the CREATION of all space and time, expanding "out" into nothingness.  NOT just a vacuum, but NOTHING - no space or time.

So we can't point to a "place" and say that's where it occurred, because there was no space defined.  In fact, it didn't occur "somewhere", it occurred "everywhere" - because all energy which eventually became the matter of our universe was confined within the "bang" itself.  This is a very difficult concept to understand, because it violates our everyday experience.  But there's no such thing as pointing our telescopes in the "direction" of the Big Bang because it was everywhere in the universe.  

If it didn't occur "somewhere", did the Big Bang occur "sometime"?  After all, there was no time defined until the Big Bang.  If we believe the speed of light is a constant since the Big Bang (as Einstein predicts), then energy (light) takes a finite time to reach our telescopes.  The energy has been spreading out into nothing (as space-time itself expands) since the Bang.  So we can look at any direction and see "old energy" or "old light".  If we look at a nearby Galaxy, that "old light" is only two million years old.  But if we look to the furthest places we can, that "old light" is more than ten billion years old.  Theory predicts that the Big Bang (if it occurred) happened between 13 and 15 billion years ago (but we'll never "see" that long ago, because there was no "space" defined yet!). In fact, as we try to see "the beginning" - at 15 billion light years - the galaxies are "receding" at the speed of light.  But that doesn't mean they're actually "speeding away" - in spite of what the popular press would have you believe.  As we look "back in time", space-time itself was extremely curved (warped in four or more dimensions).  This is similar to space-time around a black hole.  One way it manifests itself is a huge gravitational field, which also produces a red-shift.  So galaxies are apparently receding, but only because space-time is warped!  This is a direct consequence of relativity.  If our universe could somehow be viewed from a distant universe (not affected by our warped space-time), the galaxies may not be receding at all - they might just appear to the "bobbing" in a rippled space-time sea.         

I know this is all very confusing (it's perplexed the best minds in history!).  But I hope now you can understand why I can't talk about "how fast" we got here from the beginning.  Speed implies movement in space and time, and there wasn't any such thing to measure speed against.  The only thing we can say with some certainty is that space-time itself probably propagated out from the initial "disturbance" at the speed of light (since we now think gravity propagates at that speed).

Since you're so interested and you ask a very profound question, I'm going to recommend a book to you.  There are many books on the popular market, but this one was written by three of the most respected astronomers/cosmologists in the world.  And they have major problems in accepting the Big Bang.  According to these authors, the background microwave radiation at about 2.7 degrees Kelvin (which some people say is evidence of the Big Bang radiation) could easily be accounted for as the remnants of energy created in stellar nuclear fusion.  They argue very convincingly for "continuous creation", whereby matter is being continually created from the universe's energy (and some of that matter decays back to energy).  And the redshift of galaxies (which seems to indicate galaxies are receding from the Big Bang) could have other explanations.  In fact, there are too many problems with the Hubble Redshift that there MUST be other explanations.  That book is "A Different Approach to Cosmology: From a Static Universe towards reality
http://www.amazon.com/Different-Approach-Cosmology-Universe-towards/dp/052101926

That book gives the entire history of cosmology from 1914 to the present, and they insist that today, many former physicists became cosmologists for the funding, and behave like sheep, blindly following the Big Bang theory.  It requires only first year calculus (in some chapters only).


If you're still interested, I recommend "Seeing Red" by Halton Arp, another very respected astronomer, who insists that galaxies' red shifts do have other explanations - and he describes them in detail.  In particular, he describes how the "accepted" velocity-distance relationship can't be correct.

I hope I've given you some food for thought.  It's a difficult subject to understand, and many scientists do not agree on an answer.  But always keep an open mind on the subject.


Prof. James Gort

Answer
Hi Brian,

Yes, the Hubble constant seems to work for "nearby" galaxies, but once you start getting speeds which are an appreciable fraction of the speed of light (greater than 10%), the linear relation breaks down.  The speeds of recession seem to approach c as the distance approaches about 15 billion light years. This is again a consequence of relativity.  But I urge you to keep an open mind, and don't believe everything you read about Hubble's constant.  As shown in the references I pointed out to you, there may be some major inconsistencies with Hubble's "Law".  Good luck in your further reading!

Prof. James Gort