This week is the 213th meeting of the American Astronomical Society in Long Beach, California. I’m here along with many of my friends and colleagues from across Astronomy Cast, 365 Days of Astronomy, IYA, and Galaxy Zoo. Since we’re all new media, Fraser and I were able to twist arms to get help live casting the conference to the world (which happens to include you). Joining me in person are: Fraser Cain (our second time meeting in person!), Ian O’Niell, Michael Koppelmann, Chris Lintott, Georgia Bracey, Scott Miller, and Jordan Raddick. Nancy Atkinson is also helping us from afar. Together, we’re going to get you as much content as we can. (Want to meet us? Join us at Rock Bottom Brewery 6-9pm on Wednesday Jan 7)

I’m currently in a pre-meeting symposium for recipients of the National Science Foundation’s Astronomy and Astrophysics Postdoctoral Fellows 2009 Symposium. The two-day symposium is a mix of presentations by recipients, panels discussions by folks the NSF thinks have something to share (I’ll be on a panel on non-traditional public outreach), and general resources on how to get their next job, their next grant, and to teach their next class.

(I have to admit I’m learning stuff)

And one of the things that is particularly cool is they are being taught through example that it’s okay that sometimes research that just doesn’t give you the results you want or expect.

Case in point: Rachel de Naray presented her research comparing actual observations of Low Surface Brightness Galaxies to theoretical models of galaxies with a specific type of dark matter halo called a Navarro -Frenk -White (NFW) potential. These models have a specific distribution of dark matter, make a specific set of assumptions, and you can read about it here on wiki. The question is: Does this model mimic reality.

de Naray is working to answer that question. One of the best ways to approach this problem is to find a system where dark matter dominates so that the errors introduced by trying to sort luminous matter (of which you will never be abe to detect all of it) from dark matter is only a minor player. (Think of it as trying to weigh water that has on few leaves swirling in it, versus trying to weigh water that is black from leaves floating in it). Nature offers a convenient solution: Low Surface Brightness galaxies do have some stars and gas an dust, but in general are under dominated by dark matter. The stars /  gas / dust act like leaves swirling in the water, and allow us to measure how things orbit in the systems’ gravitational fields, but they are such a small part of the total mass we know how to deal with them.

One of the nice things about galaxies is stars / gas / dust (the stuff we can see) orbits at velocities that are directly related to the size of the orbit and the amount of stuff (luminous and dark) inside the orbiting object’s orbit. This means that the orbital motions of the stuff we can see tell us about the distribution of the stuff we can’t see.

So… De Naray made observations. She made models using the NFW potetial. She compared them hoping for a match, and… They didn’t match. But she initially made the simulation easy by assuming perfect data acquisition, circular orbits, axial symmetry (the distribution of the dark matter is a sphere), and she ignored the finer details of how dust / gas collisions effect things. The fact that the match wasn’t perfect was sad, but there was lots of room to try and make things better. As a good scientist, she systematically removed each of these simplifications from her simulations, seeking help from a collaborator with great galaxy models, and … Still no match. In fact, she purposely “built” an artificial galaxy with her pre-assumed distributions of luminous stuff and a NFW potential and double checked that she could recover it’s distribution, with the software, and when you artificially created the galaxy her results were dead on – the software works – but it appears simulation just doesn’t match reality.

Now here is where I’m going to through out some editorial comments. First, I loved listening to her systematically go through and say, I made these assumptions and I made these simplifications, and then I removed each of the simplifications to check my assumptions, and well, something is wrong – this model doesn’t match well. She did good work and communicated well. It was a pleasure. That said, NFW models are one of the most commonly used dark matter distributions, and I honestly wonder how long it will be before enough people say, “Hey – doesn’t fit reality so well” before people start chasing new dark matter distributions. It is going to be interesting to watch over the coming years.

At Dragon*Con (which I won’t mention again until next summer) some fascinatingly misguided person suggested that ghosts are made of Dark Matter. Dark matter is the missing 22% of the stuff the universe is made of. This is stuff – it is just stuff that doesn’t interact with the electromagnetic force in a noticeable way. This means it does not obscure light (like dust), it does not give off light (like stars), it does not chemically interact, or in fact it does not do anything other than move stuff with its mass via gravity. This means that if you can see something, it is not Dark Matter. This means that if you can detect something as a cold spot (which implies something happened to the heat energy in that spot), and if you can measure something via some electromagnetic something (changes in inductance, conductance, etc of air), it cannot be dark matter.

I do not believe ghosts have been proven to exist.

That said, the folks trying to prove they exist have “results” based on stuff that requires ghosts interact via the electromagnetic force.

If dark matter was as visible as they claim ghosts are, my job would be a whole lot easier. Dark Matter can only be detected via gravity. Ghosts cannot be made of dark matter based on any of the “Observables” ghost hunters tote out.

One more point: if you try and claim ghosts use gravity to move stuff around, then they couldn’t selectively move things because they’d need HUGE amounts of mass to move a small chair, and in the process they’d probably bend walls and collapse ceilings. They could not simply push or pull on the chair because without the electromagnetic force at play, dark matter pretty much just passes straight through normal matter (like chairs).

In case you missed it, ghosts are not made out of Dark Matter.

Try again, and please stay out of astronomy next time.

This is a place where the big teams present their big results. In fact, the COSMOS team presented dark matter and baryonic matter maps of the large-scale structure of the universe as a function of time. It was a truly tremendous result that Phil Plait wrote an excellent blog entry about at Bad Astronomy. I also caught a short interview with one of the team members, Richard Massey, which I’ll be incorporating into an Astronomy Cast episode in the next week or so. (As new results come out, I’ll be posting about them here.)

And everyone is here. This is the place where everyone presents a poster presentation or a 5-minute oral presentation on their latest results (I’ll have my name on two presentations, one on Dorrit Hoffleit, and one on online education). This is a place every student comes to try to schmooze their way into the next stage in their career, whether it be a summer internship, graduate school, or their very first post doc. In fact, this is the place any one in search of a job comes to try and schmooze their way into the next step of their career (including me!).

With such a large chunk of the astronomical community in one place, it’s possible to inadvertently run into people whose names usually only exist in things you read. Last night I hung out with Carolyn Collins Peterson, Phil, and other science education folks. Carolyn blogged a bit about it over at the Space Writer Blog. Earlier today I saw Alan Boyle of the Cosmic Log and became a momentary fan chick, thanking him for doing so much to promote and help those of us little guys and gals doing independent blogs and podcasts. It seems every time I turn around there is a new neat person to listen to, learn from, and of course foist business cards on to and out of.

And there are moments of weirdness. This Conference is at The Washington State Convention and Trade Center, and side by side with our astronomer conference is the The Seattle Wedding Show. This means that at one point a bunch of us were going up the escalator in search of NASA schwag while a bunch of “bride to be”s were coming down the opposite elevator with wedding schwag. It also means that at one point during a press conference on the Andromeda Galaxy’s extended halo, “Here Comes the Bride” could clearly be heard in the background.

And sometimes people watching (all “brides to be” aside) is just fun. There are at least 4 people (including me) with unnaturally red hair lurking the conference. And there are the normal freaks and geeks of the community, with their crazy hats, or crazy hair, or just crazy craziness. Anyone who thinks we are a straight-laced community doesn’t know the right people. NASA’s Jeffery Hayes was throwing around the world, occasionally hurling the Earth at unsuspecting souls (he claims women catch flying terra firma 80% of the time to men’s 20% of the time). People generally flew around grabbing up satellite paper models, posters, the occasional project emblazoned jump drives, and gobs of pens like kids in a candy shop where everything is free. Sure, to look at us, it’s a group of grey haired old men with a few women and flocks of undergraduates mixed in for flavoring, but all the flavoring is really spicy.

So, it’s a circus, and I am one of the side show freaks, but I’m in good company. Maybe tomorrow I’ll catch a cool release from a data contortionist or have a chance to see the bearded satellite.