MICHELE NORRIS, host:
A visitor from the outer edge of the solar system should be visible in the night sky this week. It is Comet Lulin, discovered less than two years ago. And tonight the comet will be at its closet point to Earth, about 38 million miles away. Kelly Beatty had been watching Comet Lulin approach. He's senior contributing editor of Sky and Telescope magazine. Kelly, is it putting on a good show?
Mr. KELLY BEATTY (Senior Contributing Editor, Sky and Telescope Magazine): It's all in your perspective. For astronomers it's a great show because we don't get these comets very often. For someone going outside and expecting to be bowled over it, they're going to have a hard time finding it. You'll need to know where and when to look.
NORRIS: Okay, well, where and when should we look?
Mr. BEATTY: It's going to be in the eastern sky. After it gets dark, look for two bright stars near the horizon - one is the planet Saturn, the other is Regulus, the star. And for the next few nights, Lulin will be somewhere between them. So, if you've a pair of binoculars, look in that general area, and you have a good chance of spotting it.
NORRIS: And it's said to have a tail and an anti-tail. What's that?
Mr. BEATTY: Well, yeah. An anti - it's a perspective thing. It looks like a sword in the sky in some of the photographs with one tail kind of sticking out in front and the other behind. We happen to be going by the comet in just such a way that we see the tail sticking out on both sides at the same time.
NORRIS: Now, this is a newly discovered comet - a pretty great story about how it was discovered in the first place.
Mr. BEATTY: Oh yeah, it is. The comet was discovered based on photographs taken at an observatory on the island of Taiwan. But the person who first spotted was a 19-year-old student at an university on mainland China.
NORRIS: It's a pretty great discovery if you're 19.
Mr. BEATTY: It certainly is. Usually a comet is named after the discoverer, but in this particular case, it's named after the observatory - the Lulin Observatory in Taiwan where the pictures were taken.
NORRIS: Kelly, explain this for me. I've read that this comet is going backwards around the sun.
Mr. BEATTY: Yeah, it's kind of on the wrong way in the interplanetary expressway. It's traveling almost exactly opposite in the direction that the earth and the other planets go around the Sun. This means that it must be coming from hundreds of thousands of times farther away from the sun than the earth is, in a great pool of comets known the Oort cloud. And it's its first time coming by the sun, and it's really putting on a pretty good show.
NORRIS: The first time coming by?
Mr. BEATTY: Right. These comets were formed when the solar system was four-and-a-half billions years ago, and they've been in a deep freeze all this time -way, way out there. When they get nudged in, so that they kind of fall toward the sun, they experience warmth of sunlight for the very first time and that's what causes gas and dust to escape from them and create a cloud around them, which gives the comet its characteristic tails.
NORRIS: And Kelly, if we want to get out there and try to find Comet Lulin, how much more time do we have?
Mr. BEATTY: Well, the comet will continue to get fainter and fainter in the months ahead. Right now you can see it with a pair of binoculars. In another couple of weeks, you'll need a small telescope and in another couple of months, you're going to need to go to a mountaintop observatory.
NORRIS: But binoculars right now.
Mr. BEATTY: Absolutely.
NORRIS: Kelly Beatty, thanks so much.
Mr. BEATTY: Anytime, Melissa, thanks very much.
NORRIS: Kelly Beatty is senior contributing editor of Sky and Telescope magazine.