Comet May Reveal Solar System Secrets
PILGRIM: NASA says that its Deep Impact mission was truly a smashing success, and NASA hopes crashing the Deep Impact probe into a comet will reveal secrets about the beginning of life. Well, the impacter was vaporized when it slammed into the comet. Twenty-three thousand miles an hour it hit early yesterday. That's the speed it would take to fly from New York to Los Angles in six minutes. That's pretty fast. Now, for more on the importance of this historic collision, I'm joined by Charles Liu, who is an astrophysicist at the American Museum of Natural History. And it's always a pleasure to see you, Charles.</s>CHARLES LIU, ASTROPHYSICIST, AMERICAN MUSEUM OF NATURAL HISTORY: Always glad to be here.</s>PILGRIM: And you can sort this stuff out for us. I mean, it does seem like a bunch of scientists got together and said, "Wouldn't it be fun if we just..."</s>LIEU: That's kind of what it is.</s>PILGRIM: Explain what happened here.</s>LIU: Well, comets are really interesting, because they have material locked up from the beginning of the Solar System. This is water, ice, and dirt that's been around for 4 1/2 billion years, almost untouched. And so the idea was to take something about the size of this table, and move it into the path of an oncoming comet that's coming at 23,000 miles an hour and let them hit.</s>PILGRIM: Yes. Is it hard to actually coordinate? I'm sure it's impossibly hard, yes.</s>LIU: It's challenging. The projectile that was sent by the Deep Impact spacecraft is actually a smart projectile, as it was called. It had its own guidance system, and it made three small maneuvers, with small rockets to make sure it was right in the path when it came. And right now, we're seeing as it hit. We're seeing the texture and the surface of the comet, and three seconds before it hit that's what it looked like to that smart projectile as it wound up in the surface. And then it sprayed up a huge amount of the material. It dug a hole. We're not exactly sure yet, but I think it's something around the size of a football feel and maybe six or seven stories deep. The ice sprayed out into space. And the idea is now we're going to see what was inside there, get some insights into the early Solar System.</s>PILGRIM: It's like a core sample, isn't it?</s>LIU: Very much so.</s>PILGRIM: Yes.</s>LIU: Philosophically speaking, here on Earth, when we want to know what's inside a rock, we take a hammer and give it a whack. This, thanks to the Deep Impact team, is humanity's way of giving a comet a whack.</s>PILGRIM: What -- what, besides this exact study, what's the broader perspective on this whole thing?</s>LIU: There are two things involved. One, aside from studying the specifics of a comet, we sometimes are concerned that maybe years from now, a comet will actually come and hit the Earth, causing great damage. It's likely, for example, that the comet killed the dinosaurs 65 million years ago. By creating another impact, this time in a controlled circumstance, millions of miles away, we may be able to learn more about how to protect Earth itself if a comet is to come our way. What should we do to maybe deflect it or to damage it, to move it out of harm's way?</s>PILGRIM: So we know how solid it is and all that sort of stuff?</s>LIU: The structure.</s>PILGRIM: When will we get that data?</s>LIU: It's going to take weeks and months. The first pictures are spectacular. We know that it was a smashing success, and the idea now is over the next days and weeks and months, maybe even years, we'll analyze it very carefully. There are a great number of scientific data and instruments. Well, there are many instruments with a lot of detailed equipment. And hopefully that information will come down and we'll learn something that we've never learned before in the past.</s>PILGRIM: You always make it so fascinating. Thanks very much for being here, Doctor.</s>LIU: Always a pleasure. Thanks so much.</s>PILGRIM: Well, still ahead, NASA says Deep Impact was a success, but one Russian astrologer doesn't agree. Why she's suing NASA, when we return. Plus, the result of tonight's poll and a look at what's ahead tomorrow. Stay with us.