Dark Matter Haters to the Left

September 5, 2011 2:40 PM

When we talk about dark matter and its alternatives, we are talking about no less a task than explaining the structure of every large object in the Universe. On the largest scales dark matter blows all of its competitors away. In terms of explaining the large-scale structure of the Universe, not a single one of dark matter's alternatives comes close to mirroring its success. But of course, that doesn't stop the sensationalist headlines from rolling in. We are understandably uncomfortable with the notion that we are not the most important thing in the Universe. We've just successfully figured out where the new material to form the Milky Way's young stars is coming from: high-velocity intergalactic gas clouds! About a Sun's worth of gas falls into the Milky Way (on average) every year, and this resupplies the Milky Way's gas reserves, which get eaten up as new stars form over billions of years. But what about the other, larger mystery? What about reproducing the structure of the Milky Way itself?
posted by 2manyusernames (17 comments total)

perhaps virtual antimatter particles in fact do [exist], and behave as though they have negative mass. This could, in fact, explain why individual galaxies look the way they do.

Virtual antimatter particles with negative mass.. that might explain the global sovereign debt crisis.
posted by stbalbach at 3:06 PM on September 5, 2011

I dunno. What about it?
posted by LogicalDash at 4:06 PM on September 5, 2011 [1 favorite]

perhaps virtual antimatter particles in fact do [exist], and behave as though they have negative mass.

Hmm, I'm pretty sure that antimatter has positive mass. The Anti-electron has the same mass as an electron, the anti-proton has the same mass as the proton and so on.

On the other hand Virtual Particles are the ones with negative mass. When virtual particles pop into existence, they do so in pairs with negative and positive mass. That's how you get Hawking radiation

It's not good to just mix things up. Of course the author could have been talking about particles that were both antimatter and virtual. Also, you replaced "do just that" with "exist" when in fact the author meant something like the particles having some sort of gravitational dialectic effect -- not whether or not they exist.
posted by delmoi at 4:54 PM on September 5, 2011 [1 favorite]

Every time there's a post about dark matter, someone comes up and posts about how it seems awfully handwavy.

Except of course it just takes one leap of faith ("What if there was matter that was totally transparent to everything except for gravity?") compared to the God-knows-how-many that alternative theories do.
posted by BungaDunga at 5:25 PM on September 5, 2011

I'm not sure I trust a science article that includes an animated gif of cheerleaders saying "haters to the left", unless that article is about the science of "sick-burn".
posted by runcibleshaw at 5:45 PM on September 5, 2011 [1 favorite]

Dark matter? Let me point to the post where I was totally schooled by physicsmatt. The meat starts here, and there's lots of good stuff further down.
posted by benito.strauss at 5:46 PM on September 5, 2011

I understood this!
posted by Mojojojo at 5:55 PM on September 5, 2011

Every time there's a post about dark matter, someone comes up and posts about how it seems awfully handwavy.

It's not handwavy to point out that there is something wrong with the science. Either our model of gravity is wrong or there is a lot of matter out there that's unaccounted for. Until we get some proof of exotic matter or new physics, any hypothesis is just that, an educated guess.
posted by empath at 6:25 PM on September 5, 2011 [1 favorite]

I have often wondered if dark matter is a kind of 1800s aether, a placeholder until better theories arise, harbingers of the kind of scientific revolution seen in the first two decades of the 1900s.
posted by Blazecock Pileon at 6:30 PM on September 5, 2011 [1 favorite]

In some sense it is like aether, but there is way more evidence for unaccounted mass than there is for any of the other theory. It is also simpler than most of the other theories unlike aether for it's time. Aether had a ton of kludges
Basically the point of the articles in the post. Yes scientist have biases for their pet theories (*cough* string theory), but in the end evidence rules.
posted by roguewraith at 6:49 PM on September 5, 2011 [2 favorites]

Well... dark matter might might be like epicycles, a phenomenon that everyone was sure existed and matched all of our observations until we realized that the planets had elliptical orbits around the sun, rather than circular orbits around the earth.
posted by empath at 7:22 PM on September 5, 2011

5%, dude, 5%.
posted by stavrosthewonderchicken at 1:12 AM on September 6, 2011

We are understandably uncomfortable with the notion that we are not the most important thing in the Universe.

Oh yeah, doubts about dark matter are basically medieval anthropocentrism. But then of course, 'dark matter' with its echoes of ancient beliefs about powerful 'dark' cosmogonic forces is basically a Bronze Age doctrine, isn't it?

I mean, let's not do this.
posted by Segundus at 1:39 AM on September 6, 2011

Let me put it this way. Dark Matter theory is wrong. Why? Because it is a model and every model has it's limits. There are things it can not account for. Right now we are bumping against a lack of evidence in high energy physics and astrophysics. It's been a while since I done anything in the field of physics, but last time I talked to folks about dark matter or string theory it has been that physicist are waiting for more evidence. Unfortunately, experiments that probe the fundamental nature of space and time are not things you can do with a room size particle accelerator or with a few people. Maybe the LHC will reveal more, but that will take a few more years.
posted by roguewraith at 4:02 AM on September 6, 2011

I'm not sure that's a correct thing to say roguewraith. I mean, you don't say that Darwin's theory of natural selection is wrong because it can't explain how transistors work.
posted by edd at 5:13 AM on September 6, 2011

Dark Matter theory is wrong.

There is no Dark Matter theory. It's just an observation.
posted by empath at 5:15 AM on September 6, 2011

empath: I think it's a little more than that now. The modern suggestion of cold dark matter is explicitly suggesting that there is a large quantity of largely collisionless matter which rarely if ever interacts by anything but gravity whose particles have a mass above some limit. It's constrained by observation certainly, but it's saying what explains those observations - some form of matter, rather than substantially different laws of gravity.

I might look out of the window and say that I can see an elephant, but to have a theory that there is an elephant outside my window is different from saying that there is something that looks like an elephant outside my window, or that someone has replaced my window with a remarkably good 3D TV which is showing a picture of an elephant, or merely noting down what I said about what I could see.
posted by edd at 5:21 AM on September 6, 2011