Tuesday, October 25, 2011

Gold Miners on the Moon?

Discovery News recently posted this somewhat irritating article entitled Does China Want to Own the Moon? based heavily on quotes from Robert Bigelow, founder of Bigelow Aerospace, who naturally would have nothing to gain from more U.S. investment in space travel technology, nudge nudge, wink wink. He apparently feels the best way to drum up business is to shout OMG CHINA!!! THEY WANTZ OUR MOON!! Well, race baiting aside, what would China want with the Moon?

Helium-3, Bigelow claims. Oh, lots of people claim it. Every time someone asks, "What's really valuable on the Moon?", the cry goes up for Helium-3. It's actually worth a lot of money because we don't have much of it left on Earth. We obtained it in the past mostly by detonating nuclear bombs, and we don't do that much any more. But what we use it for is mostly experimenting with what we could use it for.

The theory is that we could use it to create cleaner fusion-based nuclear plants. How realistic is this? Scientific opinion varies widely. The University of Wisconsin is ready to start mining now, even though the fusion-based Helium-3 plant hasn't been invented yet. NASA takes a more conservative view, noting that "tens of millions of kilograms of regolith must be mined to obtain one kilogram of He-3" and "Of course, this story depends on the successful demonstration that the He-3 reactor will work." The real cynics are over at the fabulous science literacy blog Depleted Cranium, whose author states baldly "Helium-3 from the Moon is not going to solve our energy problems."

Okay, so Helium-3 is a little premature. What else is up there? Metals, right? Every headline after LCROSS slammed into the Earth announced "Water and Gold found on Moon!" This PBS article is laid back in comparison, holding off on announcing gold until the first sentence. But none of the articles explain anything. How much gold? How did it get there? By the way, if you Google "Gold on the Moon," you'll get a lot of crazy links that will remind Futurama fans of this episode. (You'll also learn about astronomer Thomas Gold, though, who first predicted that the Moon would be covered in dust, which balances out the Nazi Gold Hidden on the Moon insanity.)

The closest I could come to figuring out how gold got on the Moon was this blurb from Astronomy Cafe stating that meterorites containing gold slam into the Moon, but it seems like we might as well just get the gold directly from the meterorites somehow.

So, no gold miners on the Moon. However, I have to say that I started researching this subject with a huge dose of skepticism and ended up revising my opinion on lunar mining. I don't think it will be gold or Helium-3, but we'll be up there and we'll be mining. My bet is that we'll go after titanium, which is plentiful on the Moon, and we'll also mine oxygen and hydrogen to keep lunar colonies supplied with water and air. I really hope I get to find out in my lifetime if my guess is right.

Thursday, October 20, 2011

Getting Sidetracked by Huge Animals

I meant to write about the Global Alliance for Clean Cookstoves, but it is impossible to run out of science ideas to write about, and my daughter was home from school so I got sidetracked showing her one of my favorite books: Our Continent, A Natural History of North America (published by the National Geographic Society in 1976). I used to page through this book for hours when I was young, and I was fascinated by the huge die out of large mammals right after the Ice Age that resulted in the Aztecs eating guinea pigs and human flesh. The book has fantastic pictures of the extinct animals, like elephants with alligator maws and tiny horses and land hippos. But why did they all die out, not during the Ice Age, but after conditions had improved?

The prevailing view in 1976 blamed man. The book quotes Charles Darwin, "What havoc the introduction of any new beast of prey must cause in a country, before the instincts of the indigenous inhabitants have become adapted to the stranger's craft or power." The theory is that man traveled over the Bering Straight and hunted the North American megafauna to death. Like all theories, this is based on observable data, namely the increasing sophistication of the Clovis spearpoints found in archaeological digs. But this brings up so many questions. Why wasn't there a die-out of megafauna in Africa as humans learned to make tools? Does anyone have an example of an animal that did adapt to human hunting techniques? And were there enough Clovis people spread throughout the entire continent to kill off 33 distinct types of large mammals? If so, how did the bison survive?

Today, some scientists believe that the large animal populations were already weakened by the time the Clovis hunters came on the scene. Disease and climate change could be accomplices. A really interesting idea is the second-order predation theory: as humans killed off carnivores, herbivores became overpopulated and overgrazed the land, creating boom-or-bust cycles for the vegetation, prey, hunters, and everyone involved. Unfortunately, this doesn't explain why bears and jaguars didn't regulate herbivore populations.

Finally, some scientists propose a comet theory, because that's what scientists do. A bunch of species die? Let's talk giant explosion! In 2009, evidence was found of large comets falling in North America, but nobody's found the gigantic crater you might expect from such a disaster.

The Illinois State Museum now states on their fun and excellent website "scientists do not know for sure" why these animals went extinct. We thought we knew in 1976, but now we don't. We have better, more sophisticated tools at our disposal to find new observable evidence, like the comet evidence. It's like questioning cold cases with new DNA technology! Which is cool, I think. And I can have my opinion, but in the end, my opinion doesn't matter. Science is fact. Just because we're no longer sure what happened doesn't mean there isn't one answer for us to discover.

Tuesday, October 18, 2011

It's All in Your Point of View

Today Sean Carroll started blogging for Discover Magazine, and he wrote a pleasantly short article about multiverses, namely asking if there are any and if we'll ever know. As I read it, I got a sidebar advertisement for funny Schrodinger's Cat t-shirts. Also, my cat Caesar jumped up on my keyboard, strutted in front of the monitor, and finally settled for raking my back with his claws. And suddenly my point of view had changed about those t-shirts: putting a cat in a box sounded like a genius idea, absolutely funny. I began to formulate a theory that Schrodinger must have been a cat owner, and maybe his cat kept jumping up on the counter when he was trying to think, and thus a metaphor was born. "I'm going to put that cat in a box," I pictured him thinking, "there's no telling what crazy thing it will do next."

But, back to the article. It also starts with point of view:
The extent of what astronomers can see is frustratingly limited by the speed of light: one light-year (about six trillion miles) per year. When we look far away, we are looking into the past, and that past doesn’t stretch forever. Everything we see emerged 13.7 billion years ago from the hot, dense state known as the Big Bang, so we cannot observe anything more than 13.7 billion light-years away. If there is something so far away that its light couldn’t have traveled from there to here in the time since the Big Bang, we cannot observe it. [bolding my own]

Wow, did that sentence blow your mind? I had to read it like six times to understand it, of course, but wow. There's a ton of stuff out there that we're never going to be able to see! Or maybe there's nothing out there past the 13.7 billion light-year limit. But that's it: there's a limit, our telescopes just can't fly off into infinity and beyond.

And if we can't observe it, then we can't make any theories about it. Because listen, anti-evolution theory people, there's no such thing in science as a theory that hasn't been proven by observation. It's like that old cartoon "How a Bill Becomes a Law." Until we really look at something, it's only sitting on the steps moping, wishing it was a theory but it's only a prediction instead. Hey, do you think if I made a cartoon "How a Prediction Becomes a Theory," it would help quiet down the anti-evolutionists?

So, that's it, then. Beyond 13.7 billion light years from here, we have no theories and no way to get them. Could there be other universes out there? Maybe. Sean Carroll puts this better:
Science depends on being able to observe something, but not necessarily everything, predicted by a theory. It’s a mistake to think of the multiverse as a theory, invented by desperate physicists at the end of their imaginative ropes. The multiverse is a prediction of certain theories­—most notably, of inflation plus string theory. The question is not whether we will ever be able to see other universes; it’s whether we will ever be able to test the theories that predict they exist.

So the question of the day is what exists beyond 13.7 billion light years from Earth. Nothing? Other universes? More of the same? "Nothing" just seems so limited, like we're living inside a glass sphere. Really, don't you feel in your heart it has to go on forever? But in fact our point of view always has physical limits, whether you're an astronomer or just someone trying to pry a cat off her back. Sean Carroll ends the article by noting that the fun questions are the ones we can't answer, and I suppose he's right, but really, I find it annoying that we have this limit I didn't know about yesterday. Oh, wait, we can't just keep looking? No. No, we can't.

There's a story in here somewhere about trying to see beyond 13.7 billion light years, I'm thinking something along gothic horror lines. You have peered into the abyss and you must die! Or perhaps it's the magic talisman that introduces us to the Vulcans, but writing that kind of story wouldn't be as much fun.