December 21, 2009

What YOU Need To Know About Space Combat

Cool post by an aerospace engineer about the kind of stuff we all know we spend more time contemplating than we ought to, Gizmodo considers The Physics of Space Battles:

First, let me point out something that Ender's Game got right and something it got wrong. What it got right is the essentially three-dimensional nature of space combat, and how that would be fundamentally different from land, sea, and air combat. In principle, yes, your enemy could come at you from any direction at all. In practice, though, the Buggers are going to do no such thing. At least, not until someone invents an FTL drive, and we can actually pop our battle fleets into existence anywhere near our enemies. The marauding space fleets are going to be governed by orbit dynamics – not just of their own ships in orbit around planets and suns, but those planets' orbits. For the same reason that we have Space Shuttle launch delays, we'll be able to tell exactly what trajectories our enemies could take between planets: the launch window. At any given point in time, there are only so many routes from here to Mars that will leave our imperialist forces enough fuel and energy to put down the colonists' revolt. So, it would actually make sense to build space defense platforms in certain orbits, to point high-power radar-reflection surveillance satellites at certain empty reaches of space, or even to mine parts of the void. It also means that strategy is not as hopeless when we finally get to the Bugger homeworld: the enemy ships will be concentrated into certain orbits, leaving some avenues of attack guarded and some open. (Of course, once our ships maneuver towards those unguarded orbits, they will be easily observed – and potentially countered.)

December 18, 2009

Dark Matter Matters

As a card carrying astro-related blog owner I am contractually obligated to comment on yesterday's kinda-sorta-it-might-be-dark-matter-semi-quasi-announcement by the CDMS II group.

There had been rumors about this thing for over a week that CDMS had some kind of watershed announcement. That they had discovered dark matter (what other important announcements can DM detection projects make?), that they were publishing in Nature today, that a torrent of papers was about to hit the arxiv with analysis of this last night, that they had all learned the true meaning of Christmas and were going to be nothing but kind and generous from now on.

Yesterday, with the hype reaching a fever pitch, they held a seminar on their findings, broadcast online. Unified in the concerted effort to drive everyone crazy in anticipation they began the lecture with about 10 minutes of freshman-astronomy-level rationales for the existence of cold dark matter, before moving on to another 10 minutes of descriptions of things that were important to them but not to us, like the arrangement of the detectors and the way the data was collected. Then she threw in a joke about a spherical cow, and stalled for another 5 minutes. Finally, she got to a slide that said "Results" or something at the top, and the video completely froze. Of all the panicked, oh-my-god-just-tell-us-already, freakouts I can imagine something causing, this was way up there. When I regained consciousness and the video started working again she was on a slide that said "Conclusions," and before I could make out any of the bullet points, the camera quickly panned away and she started taking questions. It was awesome.

Anyhow, in the aftermath of that humbling experience, what actually transpired during those missing minutes has come to light. CDMS detected TWO events. But because of the way they pull events out the noise of other stuff hitting the detector that could appear as a false signal, they'd expect to find about 0.8 events in the time the experiment ran. There is a 23% chance that what they saw was just random noise. I read someone describe this as the least helpful possible result and I have to agree. It isn't enough to be a conclusive discovery, and it isn't enough to say that dark matter definitely ISN'T being seen in this kind of detector either. So unfortunately, not enough for solid results, and not much to come up with a decent parameter space constraint either. It could certainly turn out they did find it, but that will have to wait for later confirmation. Just a lot of build up, a suggestion that we might be on the verge of learning something really interesting, a clue, and then the realization that nothing has been settled and you'll have to keep waiting for answers. Kind of like an episode of Lost.

Best popular article about this I've seen: Scientific American
Cosmic Variance Liveblog of Yesterday's SLAC seminar.
Basically alright article with a non-sequitur about supersymmetry: NYTimes

Actual CDMS Paper


Why does it feel as though stuff like this actually happens? Oh yeah, because it does. Better these guys than James Inhofe at least.

December 15, 2009

Season's Greetings from a Telescope!

Merry Christmas, from Hubble:

This year, say it in stars! Send your friends and relatives best wishes for the season with our printable holiday cards. Messages of joy and peace are illuminated by the natural splendor of the universe.

December 13, 2009

Worst Article Ever

I like Slate, but this lady seriously has nothing to offer. Unless you count her frequent attempts to be the worst parent ever. Without ever really meaning to, I've stumbled across her various articles about freaking out because her sons wanted to see Star Wars (she was afraid they might like it), freaking out when her son went unsupervised in the woods of suburban Connecticut for 45 min, and discouraging her son from being curious about how magic tricks work.

Still this is a new low: "My boys love astronomy. I couldn't care less." And that's just the title.

Basically she spends the whole article complaining about how boring space is to her and bemoaning the fact that her boys are always all interested in science, instead of..well, she never really says what. Except maybe some ponderous New York Times article about the 10th year of some couple's marriage -- everyone knows how normal kids really eat that stuff up.

I have never willingly studied a single page of astronomy. My knowledge of the planets begins and ends with My Very Elderly Mother Just Sat Upon Nine Pillows. [...] And yet my boys are in love. They ask for library books about outer space. They had a DVD of the moon landing. They go to the local planetarium. They recite facts about planetary gasses and burned-up stars and black holes and something else called a white hole. "Mom, did you know?" they ask before launching into a minilecture. I never do. Nor, if I'm honest, do I care to find out. The other day, Eli interrupted himself in the middle of a shooting star explanation and said, sagely, "Mom, sometimes you don't really listen to me."

This leaves me with a guilty question: What do you do when your children's interests don't match your own? Do you do your utmost to cultivate genuine enthusiasm and expertise? Do you fake it? Or do you keep the faith with your own passions, figuring you're teaching a lesson about assertion of selfhood and independence?

I am tempted to stray down the last path—is that the one for the lazy, self-involved parent, or is it the proudly resolute one?
Um, lazy and self-involved. Next question?

What kind of quandary is this? These are elementary schoolers. Is she aware of the range of stupid crap they could be into? And she's second-guessing the one that's actually educational? Sure, they're just kids and no one is saying that they're going to do whatever they're interested in now, but having your mother casually dismiss your nascent curiosity in the natural world is not helpful.

And then there's this garbage:
Maybe he'll be a rebel astronomer, and someday reform NASA, or call for an end to manned space missions so that the money can be used to fix Social Security? A mother can dream.

There are so many things wrong with that statement that I don't even know where to begin. First of all, NASA's budget is insignificant compared to Social Security (or practically anything else the government spends money on). It was $18.7 Billion in 2008, while SS was $696 Billion*. Studies show that Americans overestimate NASA to be one of the largest federal agencies, believing that it receives a quarter of the budget, when in reality it gets less than 1%. Plus a large fraction of astronomers do not favor manned space exploration, other than the role it plays in maintaining space-based telescopes, which are tremendously important.

Eliminating NASA, and all other publicly-funded science for that matter, and spending that money on other stuff would increase funding for social programs by ~2%, does anyone think this would make a huge a difference? This is one of those non sequitur "let's solve our problems on Earth first" (before ever doing science, apparently) statements that stupid people make without considering where their iPods and laptops come from.

Oh, and she cites Gregg Easterbrook. So all in all, not good.

*This chart is pretty good for showing federal expenditures visually.