I agree this makes little sense.

But I'm saying that this makes much less.

Can you meaningfully compare those two small numbers? Let's see your back-of-the-envelope calculations.

Dark matter's not that hard to explain. It's basically just the idea that when an object becomes super massive, it collapses on itself and the gravity becomes so powerful that light cannot escape from it. What's mysterious or hard to believe about that?

Also, this idea's based on actual evidence (due to galaxies orbiting invisible objects or disappearing behind dark areas occasionally, as well as more complicated reasoning that can't be explained in a short paragraph. Unlike the idea of a God which was brain-washed into people over generations despite no corroborating evidence whatsoever.

documented eye-witness testimonies of miracles performed by jesus isnt evidence? it may not be the evidence you want but its evidence

Black holes have nothing to do with dark matter or dark energy.

Most PhDs already don't get Nobel prizes.

Sam Harris reviews Francis Collins' book here: link.

and his last, unfortunately?
that was one of the most intelligent and enlightening things i've ever read

hey youngdro, how young are you? do you mind telling the forum a little bit about yourself - like your age, sex, race, religion, etc.?

"Black holes have nothing to do with dark matter or dark energy."

Has this been established? I'd like to see the argument.

Well obviously they have something to do with dark matter, but not so you can confuse one with the other.

http://www.tektonics.org/scim/sciencemony.htm

There's a link naming hundreds of Christian scientists...there's an alphabetical index, along with tons of other resource links.

Project Steve (List)

First heard that from Bill Hicks.

Acid really is great.

I am not going to explain all of GR and then derive everything for you here in the forum. Any decent text on Cosmology and most Astrophysics texts will describe that the so called "Dark Matter" has nothing to do with black holes. I will provide a rough explanation.

Basically, we observe things from emitted radiation. We are averaging over all absorbed radiation. Typical matter emits radiation as it is going into a black hole and we understand and are accounting for this. Therefore, the radiation we receive includes all information about the amount of normal matter in a region whether or not it is in a black hole.

The dark matter is basically the fact that the amount of matter seen through radiation does not jive with the observed orbits of objects. Now the radiaiton tells us pretty accurately how much normal stuff is there (normal stuff being baryons, leptons, neutrinos, and virtually any particle ever observed experimentally). This missing matter cannot be accounted for by black holes because the radiation takes into account the normal matter that falls into black holes (as previously mentioned). The dark matter would have to be of a type never observed experimentally on Earth.

"Typical matter emits radiation as it is going into a black hole and we understand and are accounting for this. Therefore, the radiation we receive includes all information about the amount of normal matter in a region whether or not it is in a black hole."

What you are saying is that we are reading the radiation that is going into a black hole along with the radiation that is not going into any black holes. But what about the matter that is already in the black hole? We are not reading any radiation from that matter. We can only be aware of that matter through its gravitational effects.

The problem, as I understand it is, that there seems to be more matter as measured by its gravitational effects than is accounted for by radiation. Since a black hole is exactly the sort of phenomenon that affects its surroundings through gravity but not through radiation, why is it not possible that black holes account for the missing matter?

I didn't see David's post but if he made that challenge, and he probably did, it just shows how narrow his knowledge of the world is.

Don't get me wrong, I am an atheist and I think religion is more or less stupid.

But I know enough about the world to know that their are plenty of brilliant people who believe in God, and things even more dubious than that.

Just off the top of my head that Aum Shindiko (sp?) cult in Japan had lots of biochemists and engineers as members.

Between the force of tradition, deep psychological needs, and the general human tendency to irrationality, you can find brilliant people who believe in almost anything.

So very true and so very well expressed.

I am telling you things every decent physicist knows. It is in any decent book on Cosmology or Astrophysics. The affect of the matter in black holes is completely included in our mass estimates given the radiation we observe from regions of space. The normal matter in black holes is fully accounted for and it is understood theoretically why the matter in black holes affects the radiation spectrum. If you don't believe me, read a book.

Dark matter has nothing to do with black holes. It is basically what you describe, the difference in mass obtained by radiation observation and by observing orbits, however, the mass in black holes is accounted for in the radiation measurements so dark matter is something totally different. If we thought it might be black holes then nobody would care about it. Black holes are understood and have been pretty conclusively observed (google hawking thorne Cygnus to see that they believe that there is conclusive evidence that Cygnus X-1 is a black hole).

My girlfriend has a degree in cosmology and she said that dark matter is that grimey stuff that accumulates in your pores. A little ProActiv should clear it up.

One PhD scientist believes in god. The other 1200000 don't.
End of story

Thanks, Cooker. Presumably you mean that we can tell the mass of a black hole by reading the radiation spectrum at the accretion disk. Presumably this would look different based on the mass of the black hole...

But what about black holes that are not gobbling up anything? The only way we can measure their mass is by the gravitational effect they have on other objects. Consequently they could be part of the missing mass.

You assert that "Dark matter has nothing to do with black holes" and you suggest I read some books on cosmology. I have and I cannot explain why black holes are eliminated any better than you have done so far.

It should also be noted that some physicists believe it is possible that there is no missing dark matter, that the problem is that our model of gravity is at fault. Gravity may behave differently at the extremes misleading us into thinking there must be more mass than we can see.

Oh wait no its cosmetology. sorry

(hopefully some of you got that the first time - when you dont reply, it worries me that you didnt think it was funny - even when we can all agree it was f-in hilarious)

No. Black holes containing normal matter are fully accounted for. To explain this would require you to know General Relativity. If you do, then I will point you to the relevant sections of MTW to reread (because if you know GR you have read MTW).

These calculations are all based on GR. There are different models suggested, but as of right now, none are considered very serious contenders. Some do take the dark matter/dark energy problem as a sign that GR is broken.