Bombing the Moon: LCROSS impact
Out of acceptable land-based targets, the United States this week went boldly where no man has bombed before: the Moon.
The Moon is, of course, the Earth's oldest enemy. Constantly messing up our oceans with its gravity... making our days longer... and who can forget when, following an attack reminiscent of 9/11, it splintered off to form its own society in the bloody revolution of 4 527 000 006 B.C.? So it's about time we got revenge.
On October 9, at 4:30 a.m. PDT, the Lunar Crater Observation and Sensing Satellite (LCROSS for short) performed one of the best experiments ever conceived. The idea is that we want to know if there is water on the Moon. More specifically, we want to know what chemicals make up the dirt under the surface, and the most important of these is water. Adding to the excitement, recent observations from a few orbiting space craft found chemical signatures that hinted there might be water in some of the craters on the Moon's poles.
The bottoms of these craters are permanently dark, and since the Moon has no atmosphere, there's no way for air to carry heat to them. That makes them very cold, which in turn means that water can get trapped under the surface and not escape to space. (Water deposited right on the surface will long since have turned into a gas and escaped into space, but a small layer of dust can lock it in.)
My (admittedly limited) education makes me think that the obervations are mostly of mineral hydroxides, and not water, but since water is everywhere in space, I wouldn't bet against it. I'm not sure if they compared the dark craters with lit craters, but that would probably help. But that's way less fun than what they did.
How do you look under the surface of a rock that is 370 000 km away? Easy... you send up a space revolver with a 2 tonne bullet and shoot it. Then you watch what comes out in the expected big cloud of debris, both with visual observations, and with a variety of more sciency things. Many of us dragged ourselves out into the cold morning air to try to watch this, but sadly, not much happened. They picked a crater that looked promising (changing the target just a couple of days before impact), but the expected dust plume didn't show up. Maybe the Moon is stickier than we thought. Cheese, anyone?
Apparently some of the good telescopes out there can see a bright patch where the bullet hit. The craft itself also crashed (intentionally), which I guess makes this more of a suicide bombing than the overthrow of a Lunarian dictatorship, but I don't know if they're spotted that site yet. There was a tiny blip on the spectrometer which suggests that there might have been water, but more will become known in the next few months.
(I heard so many good jokes about this experiment that I can not include them all here. I just have to say that my friends are awesome, and that I'm glad WTC jokes are finally acceptable to make.)
MESSENGER
In other space news, the MESSENGER craft is currently flying by Mercury for the third time, and it's sending back some nice pictures. One of the really exciting things is the discovery of volcanoes. Go to that site and browse the gallery. Seriously.
What's next for MESSENGER? Well, it's got to slingshot away for a while to lose some more speed, and they they're going to bring it back in and put it into orbit. That will happen in 2011. The path it has taken to get there is pretty complicated--again, check out their web site to see pictures of its travels and a description of what they had to do to get them. It is like the craft finished college and went on a backpacking tour of the inner Solar System.
A New Disease
Well, sort of. There's this thing called Chronic Fatigue Syndrome. It basically means that you're tired all the time. The thing is, no one is really sure that it really exists. Certainly, lots of people are tired. But is it a disease?
New research suggests that for many people, it might be. They took 101 people diagnosed with CFS, and 218 people without, and looked at the differences. What they found was that 67% of the people with CFS had a virus called XMRV (I guess that's 67 people). Only 4% of the healthy people had it (call it 8 people).
That's a striking result! There's definitely a link, and a strong one at that. The question now is: is it the right way? That is, do people get CFS because they have the virus, or are they more likely to get the virus because they have CFS? There's reason to think that the virus is causing the disease: it infects immune cells, which would cause inflammation, a common thing seen in CFS patients. Related viruses in mice lower red cell counts, which would make you tired.
It's going to be cool to see where this goes. There are also cancer research implications here, because the XMRV virus and related viruses are commonly found in prostate cancer patients. (I remember learning about cancer in an organic chem class many years ago, and I asked the professor that since RNA transcription was involved in cancer spreads, if perhaps retroviruses were responsible for some metastic cancers. He said no one knew, but that it was a good idea. Recent studies seem to be supporting this, but nothing is concrete. It looks so obvious to me, so of course it's obvious to biologists, but they still haven't shown it. The point of this story is that it goes to show how difficult this kind of research is.)
The Large Hadron Collider
I was looking this week for some more information about the LHC. For those who don't know, the LHC is the biggest science experiment ever. There's an enormous tunnel in Switzerland, and they're going to fire some protons through it at ludicrous speed, crash them together (insert Princess Diana joke), and watch what comes out (another Diana joke).
It takes enough energy to do this that they've had to reconfigure the European power grid, and they have to run at times when people aren't using a lot of electricity.
It first started up about a year ago. And ended a year ago. A short circuit blew out a big chunk of it, and it's taken a long time to repair everything and make sure it doesn't happen again. It looks like a mid-November restart is in the works, though.
The way I found out about the restart date is through an article that said someone working on it possibly had terrorist ties. Why do we even care about that? There is incredible science about to happen, and we're worried that one worker among thousands might be linked to a terrorist (or linked to a guy who is linked to a terrorist)? That drives me nuts.
Evolution of the ear
In the early Cretaceous (say, 120 million years ago), mammals were just getting a foothold in the world. The first marsupials were evolving, and Tyrannosaurs did not yet roam the Earth. Birds were starting to split off from dinosaurs. We're talking a mere 20 million years after Archaeopteryx. Flowering plants were just coming into being. In general, life was exciting.
With dinosaurs eating everything in sight, how did mammals make it through the next 55 million years to the Cretaceous-Tertiary extinction, where the dinosaurs died? By being good at hearing! The mammalian ear is pretty amazing. You have these tiny little bones, all set up to amplify sound in a big way. Sometimes, creationists will point to the ear because they have a crayon jammed in there. Other times, they will point to it as evidence for their cause, saying it is too complicated to have evolved (and therefore a god or gods--but not a spaghetti monster--created us).
Well, now we know just how it evolved! We had a good idea already, but now there is concrete evidence. (That is a fossil pun, by the way.) Maotherium was discovered in China, with fossils so good that they found fur imprints. Awesome!
What does it tell us about hearing? The word we are looking for here is heterochrony. It means "different timing," and is used in biology to say that the time in your life at which you developed some organ (or whatever developmental thing you want to talk about) is different from that of someone else, typically an ancestor. The best example is the axolotl, which additionally exhibits something called neoteny, meaning that it never grows up. The ancestors of axolotl did grow up, which makes it ever more interesting. It's like evolution is going backwards! The best part of axolotl is that you can stress it out and make it grow up. It's seriously the best animal ever, you guys.
Okay, enough axolotl loving. Ears. Ears.
Ears. Modern mammals have this bit of cartilage called Meckel’s cartilage, which holds the ear bones to the jaw as they develop. Soon before or after birth, this cartilage dissolves, leaving a functional (and sensitive) ear. Maotherium had Meckel's cartilage, but it didn't disappear! It instead turned into bone, fusing the jaw to the ear. This is heterochrony: the structure was always there, but it develops in a different way now.
So Maotherium probably wasn't great at hearing by modern standards, except that it could put its chin on the ground and hear very well. Snakes hear like this, and our common ancestor likely had a rudimentary form of it. Snakes evolved to specialize in hearing those ground vibrations, while mammals who could hear with their heads in a compromising position (in the air, while eating leaves or whatever) had an evolutionary advantage. Maotherium heard things better than the animals around it. And then there was an animals whose Meckel's cartilage didn't harden into bone. It had an advantage. And then one came along with a modern ear. And eventually, here we are! (I'm not sure if we're directly descended, but it's close enough.)
The original paper is here if you can get access. It's pretty neat.
That's it for this week. I'm off to look at pictures of axolotls! Tune in next week: same science time, same science channel.
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