Dark matter even darker than once thought

[TexasTowelie]

Dark matter is a giant question mark looming over our knowledge of the Universe. There is more dark matter in the Universe than visible matter, but it is extremely elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible Universe (see e.g. heic1215a).

To learn more about this mysterious substance, researchers can study it in a way similar to experiments on visible matter — by watching what happens when it bumps into things [1]. For this reason, researchers look at vast collections of galaxies, called galaxy clusters, where collisions involving dark matter happen naturally and where it exists in vast enough quantities to see the effects of collisions [2].

Galaxies are made of three main ingredients: stars, clouds of gas and dark matter. During collisions, the clouds of gas spread throughout the galaxies crash into each other and slow down or stop. The stars are much less affected by the drag from the gas [3] and, because of the huge gaps between them, do not have a slowing effect on each other — though if two stars did collide the frictional forces would be huge.

"We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage. Comparing how dark matter behaves can help us to narrow down what it actually is," explains David Harvey of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, lead author of a new study.

Read more: http://www.spacetelescope.org/news/heic1506/

[phantom power]

1. It's the wild color scheme that freaks me out

[Binkie The Clown]

2. "Dark Matter" reminds me of "God"

Something made up to explain something we don't understand.

The ancients saw a volcano and invented a god to control the volcano because all they understood of cause and effect implied to them that some powerful personality must be behind the working of the volcano. What? You can't see or hear or touch or detect that god? No problem. We just take it on faith that it exists. It MUST exist.

The moderns see gravitation effects and invent "dark matter" because all they understand about gravitation implies to them that "matter" must be behind the working of it. There can be no other cause of gravitational effects. What? You can't see or hear or touch or detect that dark matter? No problem. We just take it on faith that it exists. It MUST exist.

The dark matter hypothesis is just that; an hypothesis, and a bad one at that since it is in essence untestable and unfalsifiable.

I can't begin to imagine what might be the cause of the gravitational anomalies. It might be as simple as that our mathematical models of how gravity works are wrong, or as complex as the possibility that gravity propigates across parallel universes, and that "dark matter" is just bright matter in a number of adjacent parallel universes.

What I'm quite sure of is that the observed gravitation anomalies are NOT the result of some made-up invisible fairy matter.

[William Seger]

6. Good response!

> Science, real science, does not fear challenges to established ideas, rather embraces them.

[mopinko]

4. what warren said.

there is evidence.
and we used those laws of motion and gravity to put men on the moon several times. i think we have that pretty well down pat.

[Binkie The Clown]

5. We used Newton's laws until we found out they are not quite right.

Newton thought he had it "pretty well down pat." Who knows what we will learn in the future that we are not quite right about now? Being a scientist means never being able to say "we have it pretty well down pat." (In the 18th century there was a move afoot to close the patent office because "everything useful has already been invented." and at the opening of the 20th century physics was just a matter of "coaxing out a few more decimal points" in the values of the natural constants. Everything important having already been discovered.

In the present case the "evidence" is gravitational anomalies.^note The assumption, completely unwarranted IMHO, is that some kind of invisible matter is the cause. There's a giant leap between observing an effect and hypothesizing a cause for that effect. Especially an invisible, undetectable cause.

I love science. I trust science. I believe in science. My degrees are in Math and engineering, so I used science every day in my work before I retired. But I also think ideas should must be challenged. I enjoy, as a mental exercise, trying to poke holes in things like the big bang, dark matter, string theory, and other highly speculative branches of physics.

[font size=1]Note: Actually, it's not even gravitational anomalies. It's motion anomalies. Those anomalies might not even be caused by gravity. They might even be caused by magnetic or electrostatic forces. We can speculate, and hypothesize, but at the distances involved, we simply cannot know for certain.[/font]

[Binkie The Clown]

8. I pretty much hate woo.

I'm a true believer in pure science. But I also enjoy speculation. Sometimes (not always, and not even often) the craziest far out ideas are what turn out to be true. (e.g. Alfred Wegener)

Yes, we know a bleeping lot. And crackpots like Depak Chopra who throw around words like "quantum" to justify nonsense are ridiculous. But there's also a bleeping lot we don't yet know.

“As our circle of knowledge expands, so does the circumference of darkness surrounding it.”

― Albert Einstein

And don't forget Clarke three laws (quoted from Wikipedia):

Clarke's Three Laws are three "laws" of prediction formulated by the British science fiction writer Arthur C. Clarke. They are:

1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

3. Any sufficiently advanced technology is indistinguishable from magic.

[Binkie The Clown]

10. How about THIS for fringe, yet plausible?

Axiom: consciousness emerges from any sufficiently complex information processing device.
Axiom: A particular set conditions lead to that consciousness which is uniquely "me" (as opposed to someone else's consciousness, or consciousness in general).
Axiom: Either time and/or space are infinite in extent, or there are an infinite number of parallel universes. (Either or both of which result in the same conclusion)

Conclusion: After I die, somewhere, eventually, that particular set of circumstances that resulted in the particular instance of consciousness I call "me" will occur again. I will close my eyes in death, and open them again in birth in what seems to be no time at all, even if it happens 47 billion years from now. Of course memories will not persist, so I will have no way of knowing that it has happened, but in spite of that "reincarnation" is a mathematical certainty. And "I" might recur in some unimaginable biological form, or possibly in some machine of sufficient complexity. In any case, I shall return.

[font size=1 color=grey]fnord[/font]