I wanted to bitch a little bit, to an audience of people who aren't at all colleagues of mine, in the sense that they aren't people in any way involved in my field of study.

So, if you know anything at all about modern astronomy and/or astrophysics (to be clear, the former is the observational and experimental side, the latter theoretical), you've at least heard the terms 'dark matter' and 'dark energy'. They're two of the biggest cornerstones of cosmology right now, and craploads of money are spent annually in an attempt to determine better what they are. They're also often heralded as being two of the greatest discoveries in the field, like, ever.

There's just one problem: they haven't been discovered. Neither of them. And if they haven't been discovered, they can't be two of the greatest discoveries ever.

Let me back up a bit. I'm going to focus on dark matter here, since dark energy is even more of a mystery right now and hence hasn't created that many strong opinions about what it is.

So, 'dark matter', if you're unaware, is the term given to what is apparently missing mass in the universe; matter that doesn't shine and hence is not visible in our telescopes/other photon detectors. The idea came from a variety of different places: spiral galaxies rotate faster than we'd expect under the laws of gravity as they are currently known, galaxies in galaxy clusters move too fast and should be flying out of clusters all the time, and so on and so forth. So when things don't behave like they should under normal gravity, you have two options, really: either there's missing matter that's holding it all together despite the large speeds, or you have gravity wrong. The former is given the name 'dark matter', and the latter is given the name 'Modified Newtonian Dynamics' (MOND; sometimes called Milgromian Dynamics after the Israeli fellow who came up with the idea). Right now, for whatever reason, dark matter is the favored choice.

But here's the thing; it's not a perfect choice. It's actually just a placeholder, an idea injected into the body of knowledge to fix the known problems. Cold Dark Matter, the thing every physicist loves to use in their simulations, is this highly convenient, perfectly non-interacting, heavy kind of matter, so that all it does is have mass and therefore affect things gravitationally (this makes it very easy to simulate; much easier than normal matter--baryons--which constantly is interacting with itself, losing energy, gaining energy, turning into stars and planets and black holes, etc.), and it tends to produce pretty good facsimiles of what we know the distribution of galaxies is in the universe. It also does a good job reproducing things like galaxy clusters, and it fixes some problems, like why stars and galaxies apparently collapse into what they are so quickly after the Big Bang (when everything was just a haze of protons and electrons and photons).

Unfortunately, though, it does a rather crap job at reproducing individual galaxies and their satellite systems. Dark matter simulations right now, for example, WAY overpredict the number of satellites (companions that orbit it) any given galaxy is supposed to have, on every mass scale (too many little ones, too many intermediate ones, too many big ones). It also has a terribly hard time reproducing the motions of known satellites around the Milky Way (dark matter halos like to make things merge into other things super fast via something called dynamical friction; simulations of Milky Way satellites usually just turn off dynamical friction to bypass this issue). It also has nothing to say about one of the most precisely-known empirical relationships in galactic astronomy, the Tully-Fisher relation (which is so universal as to be essentially a physical law; we just don't know the physics underlying it). These are acknowledged problems, and generally the people doing the simulations try to fix them by invoking normal matter physics, things like energy feedback into the system by supernovae going off, active nuclei of galaxies shooting crap off into space, and so on and so forth. And you can certainly fix the problems by messing around with these things, but right now we don't have a solid grasp of the physics involved in such processes, in which case what the simulation folks are really doing is tweaking the nobs and pulling the levers necessary to fine-tune the result they want (which is the observed properties of galaxies; reality). But this process has no predictive power at all, and therefore sucks gleet from a dead hawk's intestines as a scientific theory.

There's also the fact that people have been doing extensive searches for the 'dark matter' particle for decades now, checking every variation of every theory they can possibly branch off of the Standard Model of particle physics to account for it, and every single experiment so far has ended in a null result (except for one, called DAMA/LIBRA, which claims to have found a signal, but it conflicts with another experiment that found no such thing so no one believes them).

To me, these things are problematic, and definitely call for more investigation into alternative theories. You know, because we're scientists, and we should be considering the evidence at hand.

But there's a super strong backlash to anyone who even brings up alternative theories (e.g. MOND). The MOND idea rarely gets funding, and apparently if you bring it up at conferences you get personally attacked, or laughed at, or generally ignored. Refereed journal article editors might ask you to adjust your paper to essentially state that your conclusions are invalid so as to avoid contradicting a more well-respected scientist (this happened to a colleague of mine). 'Dark matter', despite that it is still and has always been a placeholder idea for something nobody on Earth understands right now, has become an article of faith amongst scientists.

I'm pretty new to this whole 'science' thing, myself. I've only been seriously involved for about 4 years now. But I find the treatment of this issue incredibly irritating and incredibly disheartening. Now, I'm generalizing a bit; there are still loads of people who are fighting the good fight (otherwise, I wouldn't even know of these problems with the dark matter theory, as they would have been buried). But here's the thing: astronomy, to me, is not important enough to daily life to be placing powerful personal stakes in any given idea within it. We study astronomy because we're interested in it. That's all. It's not going to cure cancer, it's not going to solve world hunger, it's not going to create world peace. I study galaxies whose light takes 30 million years to reach us; my results are only going to affect the world from a purely philosophical standpoint (it's nice to know our place in the universe, I guess). And because of that, if someone finds out that I came to the wrong conclusion, and they can argue that point to me in a way that I find convincing, I'll change my stupid opinion and move on with my life knowing that I've learned something new. What I won't do is buckle down and start calling that person names.

And yet that's the kind of behavior we're seeing with regard to this whole 'dark matter' thing. If it's dark matter or if it's a modification of gravity at low accelerations due to quantum effects, what's the difference? These are scales that occur literally at the edges of galaxies and in the empty spaces in between them. Humanity won't be getting to either of those places for centuries, millenia, maybe never. So if you're curious about the universe, just try to find out which one it is! There are ways to test both theories, and right now one of them happens to be floundering a bit. That's because we're doing science. Sometimes you're wrong. It happens. Get over it.

So why am I telling this to you fine folks who probably don't care one way or the other? I guess just to let you in on a little secret regarding how science is actually done, and to remind you that it's a human enterprise in the end and is therefore subject to the same kind of bullshit as everything else. But let me end with this: some day, this debate will be resolved, and the best theory will come out on top, because it is science, after all. It's just going to take more time than necessary due to primate chest-puffing and posturing slowing it down, and that's what I find annoying. I wonder if humankind had descended more closely from, say, social dinosaurs, if we would have made much faster progress?