The universe is made of matter, because if it were made of the other thing, the other thing would be called matter.

I'd like to see more work on dark matter next. I find it slightly implausible and nowhere close to proven that something like 90% of all matter and energy in the universe is dark.

GAT_00: I'd like to see more work on dark matter next. I find it slightly implausible and nowhere close to proven that something like 90% of all matter and energy in the universe is dark.

All forces in our universe have a negative and a positive, except for gravity. It would not surprise me if the cost of bending spacetime (gravitation) had an equal and opposite reaction (the expansion of the self same spacetime).

This would also address the DISTRIBUTION of "dark matter", which is more prevalent the more massive objects are nearby, i.e. it is concentrated in the middle of galaxies.*

Ergo, empty space must have a massive amount of energy within it's observable four dimensional parameters. The equal and opposite force makes it fly apart. And the more mass you have, the less space expands locally. Which also points toward an explanation for entropy.

/not an astrophysicist

/I also screwed up the apostrophe in "it's", which should be "its". I blame my Methodist upbringing.

Huh huh. Large hardon.

Marcus Aurelius: It would not surprise me if the cost of bending spacetime (gravitation) had an equal and opposite reaction (the expansion of the self same spacetime).

Which is fine, except the opposite of matter is anti-matter. Dark matter gives a second version of anti-our matter. That's not balance. Plus by most calculations, standard matter is a very small percentage of all matter in the universe. That's not balance either.

It's all well and possible, but I'm nowhere near convinced. It seems more likely that gravitation has an unproven component that only is visible for large masses.

GAT_00: Marcus Aurelius: It would not surprise me if the cost of bending spacetime (gravitation) had an equal and opposite reaction (the expansion of the self same spacetime).

Which is fine, except the opposite of matter is anti-matter. Dark matter gives a second version of anti-our matter. That's not balance. Plus by most calculations, standard matter is a very small percentage of all matter in the universe. That's not balance either.

It's all well and possible, but I'm nowhere near convinced. It seems more likely that gravitation has an unproven component that only is visible for large masses.

Thermodynamics righteously demands an equal and opposite.

So you tell me.

What is the opposite of gravity?

Marcus Aurelius: What is the opposite of gravity?

A cat with buttered bread on it's back dropped from a table.

This About That: The universe is made of matter, because if it were made of the other thing, the other thing would be called matter.

Marcus Aurelius: All forces in our universe have a negative and a positive, except for gravity.

wtf are you talking about????
http://en.wikipedia.org/wiki/Nuclear_force

namatad: Marcus Aurelius: All forces in our universe have a negative and a positive, except for gravity.

wtf are you talking about????
http://en.wikipedia.org/wiki/Nuclear_force

So the strong nuclear force doesn't reverse itself?

Marcus Aurelius: namatad: Marcus Aurelius: All forces in our universe have a negative and a positive, except for gravity.

wtf are you talking about????
http://en.wikipedia.org/wiki/Nuclear_force

So the strong nuclear force doesn't reverse itself?

so you are a troll or really stupid? a fusion bomb??? bwahahahahahah fusion would be an example of the strong nuclear force. not the reversal of it.

*slowly backs out of thread*

/make that quickly

At the moment, they are claiming a statistical certainty of "3.5 sigma" - suggesting that there is less than a 0.05% chance that the result they see is down to chance.

The team has nearly double the amount of data that they have analysed so far, so time will tell whether the result reaches the "five-sigma" level that qualifies it for a formal discovery.

AKA standard deviations.

Way to make it sound complicated, author of TFA.

Anyone know whether they use arithmetic or geometric?

What a graduate of Wossamotta U might look like

GAT_00: I'd like to see more work on dark matter next. I find it slightly implausible and nowhere close to proven that something like 90% of all matter and energy in the universe is dark.

Not really. We're a speck of dust in the middle of nowhere.

The universe is the planet earth, we're an electron in the Sahara. Gods only know what the fark we haven't figured out yet.

GAT_00: Marcus Aurelius: It would not surprise me if the cost of bending spacetime (gravitation) had an equal and opposite reaction (the expansion of the self same spacetime).

Which is fine, except the opposite of matter is anti-matter. Dark matter gives a second version of anti-our matter. That's not balance. Plus by most calculations, standard matter is a very small percentage of all matter in the universe. That's not balance either.

It's all well and possible, but I'm nowhere near convinced. It seems more likely that gravitation has an unproven component that only is visible for large masses.

You're mixing two things together here that shouldn't really be combined the way you're thinking.

Matter: stuff w protons, electrons, etc
Antimatter: stuff w antiprotons, antielectrons, etc

I'm sure you knew the above, but then we get to the dark matter part. We know there has to be something because galaxies should fly apart if there was only the visible amount of matter in them that we see, and right now people are assuming it's some sort of particle or particles we don't understand. Various reasons for evidence regarding this, see The Bullet Cluster (new window). I know people like to ask about MOND, but the reason you don't hear much about modified gravity is there is no real theoretical model yet for how it could work that could be tested, whereas we can test theoretical models if dark matter's just a particle. In fact, we should spot it in the next ~10 years as if we don't we'll know it's not a particle, and in the grand scheme of things that's a rather small investment considering how long folks have been testing ideas regarding dark matter.

Anyway, dark matter the particle itself can be split up into two camps-

Baryonic dark matter- stuff made up of the normal matter (could be antimatter too, just seems unlikely) that just doesn't give off light, as in a bunch of brown dwarfs or Jupiter sized planets. There is some of this in the universe, but long story short we just plain don't see enough of it to explain dark matter.
Non-baryonic dark matter- this basically means it's not going to be "normal" matter but somehow stuff that doesn't react electromagnetically. This is what dark matter searches are usually looking for.

So in the above two categories basically the baryonic stuff would have to be normal matter, ie not antimatter, and while the jury's still out it's speculated that non-baryonic dark matter is also not like antimatter related. The reason is while most of it's supposed to float around outside the galactic halo the occasional particles do come through the inner region (and it's these the dark matter detectors are hoping to snag), so they'd annihilate with normal matter if they were made of antimatter.

So the point of my long-winded story is the matter/antimatter problem and the dark matter one are more or less separate problems. Somewhat related because theories about matter in general tend to intertwine, but these guys at the LHC aren't really thinking about dark matter at all when doing their experiment.

/ before you ask, no one knows what dark energy is, it's just a name given to the fact that we can observe the universe accelerating when it shouldn't be
// to be sure, a very unfortunate name as it can lead to confusion

doglover: GAT_00: I'd like to see more work on dark matter next. I find it slightly implausible and nowhere close to proven that something like 90% of all matter and energy in the universe is dark.

Not really. We're a speck of dust in the middle of nowhere.

The universe is the planet earth, we're an electron in the Sahara. Gods only know what the fark we haven't figured out yet.

Don't worry, no one ever said it's proven. It's just if you have a better explanation for why a. galaxies don't fly apart due to not having enough mass to hold themselves together, and b. why the universe is accelerating when there's not enough to hold it together, well there are a lot of very smart people who'd like to hear it.

It's just that is currently the best idea, doesn't mean physicists aren't working on others. And the field is constantly evolving even if you remember what was said 10 or 20 years ago; I'd be astounded if we still had the same models 10 or 20 years from now. It's just part of the scientific process is all, no one ever said our current solution is the final one.

Jake Havechek: I'd rather hear about more work on finding the graviton, if it exists. Gravity is the most prevalent yet least understood force in the universe. Sure we know the how and the what, but not the why.

That's because the current best project in the world for graviton/ gravitational waves (LIGO) is currently offline until 2014 as they update the project for advanced LIGO. When there isn't much going on in a field it doesn't make for interesting science journalism.

Jake Havechek: When there isn't much going on in a field it doesn't make for interesting science journalism.

Unfortunate. It would explain a bunch of things about space/time.

Yeah, to clarify it's not that progress isn't being made in the field or that people don't want to know the answer, it's just a rather expensive and huge collaboration. Sorta like how the LHC turned on a few years ago and we're now just starting to get the first hint of results.

Patience is a definite virtue in this branch of science. :)

THEN I GUESS IT REALLY DOESN'T MATTER.

No, seriously, great stuff. What really blows my mind is that 80% of all matter in the universe is dark matter, a form of matter which physicists don't have any clue about. All we know is that it's heavy and is not baryonic, meaning that it's stable matter that's not formed from protons and neutrons, and probably? not even quarks. And it hasn't been formed in any high-energy physics experiments. And yet, there it is, composing most of the universe.

And then there's Dark Energy, which is more exotic than dark matter and has more than three times the energy of normal and dark matter, and we have even less of a clue about that. The universe is a very, very strange place, and even now, all science has done is show us the true extent of our ignorance. Mindblowing, really.

Virtuoso80: Something had to make it go in one direction over another.

Well, I suppose that is the question. Yet, if "it" has not gone one way or the other, leaving equal parts matter and antimatter, then the matter would be moot, wouldn't it? Perhaps all matter would have recombined and turned back into energy? What would there be then? And, for us, surely it would not matter.