Expert: Tom Whiting - 1/21/2010

Question
QUESTION: To keep things as brief as possible, I understand the concept of red shifting.  I also go along with that for "near" objects we can measure their distance fairly accurately by measuring the shift or measuring light bending around known objects.  Probably garbling that up but...  However, the claim that Hubble recently looked back in time nearly 13 billion years has me asking questions:

Rather than looking at a highly red-shifted image, how do we know that we are not looking at something that is actually pretty close but relatively cool?  I.E. the red "color" is due to lower energy output than a blue or white object.  If it is because we assume that objects "way out there" have the same atomic/chemical/physical composition as the things we know quite a lot about it seems that assumption may be a bit of a stretch over such distances/times.

How confident is the astronomy world in the assumptions regarding red shifting, etc.  Seems like things/assumptions/laws might prove to be different at extreme distances/masses/time/(others?).

Also, my crude understanding of the big bang is that we are left with an expanding universe that is essentially on the surface of a sphere with a hollow core.  Is that true?  If so, how "thick" is the surface layer where all of the matter is?  Wouldn't geometry laws imply that we can triangulate back to the exact physical location of the big bang (i.e. the center of the sphere)?  In what direction is hubble looking - is it out from the surface of the sphere, in toward the center of the sphere or laterally out along the surface of the sphere?  If it happens to be looking back toward the center of the hollow sphere, could hubble be looking at matter on the other side of the sphere?

Any help would be appreciated.  This is fascinating stuff but my fascination is tempered by my engineering training where I learned the limits of making necessary "assumptions" in order to move forward with work, etc.  To me, someone could claim those objects are made out of cheese and we really have no way to check it.  Also, I worry that in order to keep "moving forward" there may be a tendency to make assumptions that are quite a stretch but lead to "fascinating discoveries" which can never be proven, anyway.  In my world, if I make bad assumptions, things break so success/accuracy is easy to measure.

Thanks.

ANSWER: Hi Robert,
Lots of questions but I'll try to do my best. There is a very very high confidence in using
Red shift as a large distance indicator. It is the highest rung of the distance ladder. Before
that we use parallax, Cepheid variable stars, the moving cluster method, spectroscopic parallax,
standard candles of Type I supernovae, each being slightly less accurate then the previous
rung.  (There is no other choice as we can't stretch a tape measure out into space)!
But when those other rungs are used, results show that there is a high correlation between using the red shift method to those other methods on very distant objects.
So we know that redshift method is not fooling us... plus it's based on the Doppler laws
of frequency and wavelength change when the source (or receiver) is moving.
And everything in the Universe is moving relative to everything else... there is no absolute
rest in space.
It's the spectrum shift, not the color red.  The various metal spectral lines are shifted to the "red end of the spectrum" (basically a doppler shift just like sound frequency and wavelength changes with a traveling sound source)... and not the color red. It's just a shift of wavelengths... to the red end of the spectrum IF something is
receding, and a blue end shift if it is approaching (or we to it, it's all relative).


ANY direction you look, you're looking back in time. All telescopes are simple time machines.
The farther out you look, the farther back in time you are seeing... standing 5 feet from me,
you 'see' me, or more appropriately my reflected light... one nanosecond, the moon 1.5 seconds, the sun 8.3 minutes, the nearest star 4.3 years, the Andromeda Galaxy about 2.9 million years, and on and on outward.  The most distant thing is the MBR, microwave background radiation of
the Big Bang, about 13.3 billion years ago, redshifted from visible light clear down into
the microwave (radio) portion of the spectrum.  (See, it's not a color red after all.)

Cheese is mainly milk products, mainly lactose and milk by-products. I don't know the chemical
formulae, but the spectrum of cheese would reveal high carbon content, various fats, and the
proper constituents of hydrogen and oxygen. We could easily identify cheese and milk byproducts
from a spectrum of the light being received and analyzed.  We know that the stars are not made
of cheese, nor is the moon.

Ok, here's a better understanding of the Big Bang... A random fluctuation at the quantum level
occurs some 13.7 billion years ago in the Primordial Void. Temperature is trillions of trillions
of degrees hot. (We as yet, don't know how this happened, and may never know, although the new
string theory gives us some new ideas to work with).
In addition to all this energy, we know that space and time are also brought
into existence at that instant. The spacetime expands exponentially (spacetime is not limited to light speed, only energy and matter are). The Universe is opaque for 380,000 years until it cools where protons can capture electrons, forming hydrogen and the Universe becomes transparent.
The Big bang influence over the past 13.7 billion years expands. We (Solar System) form up
some 9 billion years later after some heavy elements form in the cores of supernovae stars.
(We're currently up to 3% heavy elements, from Lithium #3 to Uranium # 92.  97% of the Universe is still hydrogen and helium (we've only just begun!)  WE are IN the Big Bang influence. (We cannot observe our Universe from the outside in, only from inside it outward), so this is why it does not matter which way Hubble, or any other telescope is pointing, there is no point source to find, as WE are all inside the big bang influence, so no matter which way you look, you are always looking backward in time.  We are like a raison bread rising in the oven. The raisons are the galaxy clusters... pick any raison for our galaxy and all the rest of the raisons are moving away, receding, proportionally. (The closest one is receding the slowest, the farthest one the fastest).  It matters not which raison you pick for the Milky Way, all raisons see the same proportional recession velocity.
We originally thought that the oven temperature was stable, and expansion was slowing, but since
1998, we know that 'someone' is turning up the oven heat hotter and hotter... the expansion is
actually accelerating with time, and NOT decelerating as we originally thought.
(See Type Ia supernovae studies). That is our current scenerio as we see it... or as the data shows. (What else can we go by)?  Sure beats sitting around just thinking about it, the way
the Greeks (especially Aristotle) did it.  He was quite wrong most of the time.
So see, we are not on the edge of a sphere with a hollow core after all, the entire Universe
is filled with galaxies, no matter which way you look. But normal matter only constitutes about
4% of the Universe... dark matter and dark energy constitute 96% of our Universe, and as yet,
we have no idea what these are, so we have a long way to go to solve the entire puzzle.
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA USA






---------- FOLLOW-UP ----------

QUESTION: Thanks, Tom.

Red shift vs "red" - that helped and it was something I should have picked up on.  I guess if we assume that what we know about our sun and the relatively near objects carries over to the rest of the universe then we at least have a foundation to go on.  We know how these objects "look" in a spectral analysis and their fingerprints shift with distance/speed.  The raisin bread analogy was very helpful.  

Answer
We have far far more than that...but it would take a physics and astronomy course to explain
it all...as one builds on the findings of the other.  We also have laboratory spectral
signatures of all the elements, their isotopes, and many molecules too...just as a small
example of what we already know.
Thank you,
Clear Skies,
Tom