Expert: Tom Whiting - 12/27/2009

Question
QUESTION: "Hi wondered about your views on the following idea. We have 'calculated' expansion rates of the universe. We have observed black holes and learn so much. Its been suggested that the universe could be in a black hole. Could black holes be studied closer: their different evolutionary stages,how much matter they pull in when young to old,rates of spin at these stages etc. Maybe this could be correlated to factors in our universe. What if these things could be studied closely and it was found a black hole pulls in matter extremely fast when first formed,correlating to an inflation era in our universe. Then a black hole pulls in matter at a steady rate correlating to steady expansion in our universe and so on. Couldnt observations such as these go some way to proving the universe is in a black hole? This would then allow us to take our timeline back,not up to the big bang,but beyond it. The point im making is possibly correlating any black hole behaviour to our universe behaviour! Thanks Richard"

ANSWER: Hi Richard,
Yes, I've read the theory that the entire Universe may be one giant black hole.  Don't know
if I agree with that, but I guess it's possible. We just don't know.

Black holes do not "pull" or "suck" matter in...they simply highly curve the space-time continuum
completely around themselves.  Gravity doesn't pull or suck, it simply bends space-time.
(See Einstein's General Relativity).
Incoming matter typically goes into orbit around a black hole forming a very hot accretion disk around the black hole, where the matter slowly spirals inward toward the event horizon.
Black holes only have 3 characteristics, mass, spin, and charge.
The mass is fairly easy to determine, and the charge is thought to be at or near zero.
But the spin is difficult or nearly impossible to determine. (A spinning black hole would have two event horizons).
Typically black holes do not have a "steady rate" of incoming matter. Our own black hole at the center of the Milky Way is now thought to be in a quiet phase right now. But was active
earlier in it's life. This may change someday, we just don't know.
Most astronomers think that we cannot see back beyond 13.7 billion years, the Big Bang event, because time (and space) came into existence at that moment, so if time did not exist prior, how does one see back beyond the existence of time?  When only the Primordial Void existed?
Our real limit may be the microwave background radiation at 379,000 years ABB, because prior
to that time, the Universe was opaque, not transparent. Perhaps radio and infrared can pentrate
the opaqueness someday... I think that's one of the goals of the new James Webb Infrared telescope to be launched in 2014.
Clear Skies,
Tom Whiting
Erie, PA USA

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

QUESTION: Hi Tom tyvm for your prompt response but i feel youve entirely missed my point. We study galaxies/suns etc at different stages of their 'life' to put an overall picture of how they evolve. Could this be done for black holes? Could we put an age,for instance, on a black hole in a similar way we do galaxies. I am aware of the 3 characteristics of black holes and of the limits looking back towards the big bang. The actual 'creation event' may be out of limits to us. Now im asking this only in theory/possibility,not 'well it would be hard to do.' eg accretion discs would probably have differing masses 'falling' into different black holes-it might to be hard to measure the mass falling in,but theoretically possible? As we see parts go into a factory and a car come out we assume the car was assembled in the factory. If we could measure accurately the 3 parameters of black holes+matter going into the blacks holes,and this is the crucial point,at their different stages of evolution, and compare to the evolution of our universe. Maybe we could find a pattern in black hole 'behaviour' that would correlate to some 'behaviour' of our universe. Arbitary numbers here, what if we found year 10 of a black holes life it increased its mass 100 fold and year 10 of our universe its size increased 100 fold and/or other parameters showed a relationship. Sorry tried to be bit clearer about what im trying to say! Would any of this be theoretically possible? Thanks very much   Richard

ANSWER: I don't think we can do the same for a black hole, which simply represents the most compact
(or densest) form of matter that we know of.
1. Black holes form nearly instantaneously (and initially) as the core of a massive star goes supernova and compresses the core down beyond the neutron star stage.  
2. From then on, the amount of matter 'ingested' by a new black hole would be determined where
in space it formed and how much available 'food' exists in it's surroundings.  Would it not?
So it's not age or evolution, it's location.

So if a new black hole forms near the center of a galaxy, then there is lots of potential
'food' for the hole to feast on, at least initially. Once the hole ingests the nearby local
stars, then lean times will happen... That's probably our Milky Way black hole status right now.
Being near the center of a galaxy, these can grow to multi-million solar masses real quick,
then level off.

But if it forms out in one of the outer arms of a spiral galaxy, then there is not much matter around from which to 'feast on'. So we observe black holes that are 'only' hundreds or thousands of solar masses in size.  So to me, it sounds like the old real estate mantra of
'location, location, location' is all important relative to black hole mass size... with future in-flow and mass exhibiting zero correlation with age (and evolution), because it all depends on location and it's surrounding environment, and not 'age/evolution'.  Perhaps that's why astronomers use 'other factors' to determine age and evolution of the Universe, instead of your suggestion.  If valid, don't you think we would already be 'using holes' to do that, if it was an accurate process?    Just my logical way of thinking.

PLUS, there is the additional problem that we can't really "see" a black hole; only the light
from it's accretion disk (if any) and it's gravitational influence on nearby objects. Since they
themselves give off no radiation, what is there to work with?  Nothing.  So that's why astronomers use the radiation (light, heat, etc) from objects that do give off, emit...something.  Quite a bit easier to work with something that emits light, as opposed to
a black hole which emits nothing, Eh?
Clear Skies,
Tom

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

QUESTION: Hi tnks again for reply,please tell me to stop corresponding if you wish! I wasnt suggesting dating our universe by dating black holes. I know we currently do that in other ways and have come to some answers. Im suggesting the answers we have,and continue to refine, may be correlated to information we could theoretically get from black holes. This isnt a 'method' of dating our universe. Its to see if all the parameters we have measured about our universe in other ways could correlate to any factors about black holes. So when you say its easier to measure other things,it might be easier but its black holes i wish to get the information about!! It is impossible to accelerate to speed of light-is it impossible to measure the 3 properties of a black hole-theoretically impossible? And would not the light given off from an accretion disc indicate the mass in that disc? I do understand your point about location and that black holes may not have evolution as such. This is something im trying to think around now! I really do appreciate your correspondence Regards Richard

Answer
Well, you are free to do any research you wish. Just remember to maintain the integrity
of the scientific method while doing so. That's all that counts.  Don't fly off on one of those 'metaphysical' tirades, with withering and convoluting paragraph after paragraph after
paragraph of incomprehensible jargon...remember, science simplifies, not complicates the order
of things.  (Otherwise your integrity is compromised if you go the metaphysical route).
Wishing you well,
Clear skies,
Tom Whiting
Erie, PA