NIGHT OF THE COMET
MARCH 22, 1996
JEFFREY KAYE: The Griffith Observatory in Los Angeles is just one of hundreds around the world carefully tracking the path of comet Hayakutake. The comet will be closest to Earth--nine and a half million miles away--on Monday and Tuesday. Griffith Astronomer Anthony Cook took these time exposure photographs of the comet on March 17th on a mountain outside of LA. I spoke to Cook earlier this week.
JEFFREY KAYE: Thank you very much for joining us.
ANTHONY COOK, Astronomer: You're welcome.
JEFFREY KAYE: Let's start with a basic question. What's a comet?
ANTHONY COOK: A comet is a small object in our solar system; a ball of ice and dust orbiting the sun.
JEFFREY KAYE: And this particular comet has been around this way before?
ANTHONY COOK: Yes. We think something like 18,000 years ago, more or less.
JEFFREY KAYE: And was this just recently discovered?
ANTHONY COOK: Yes, uh, this was discovered on January 30th, this year.
JEFFREY KAYE: Very recently.
ANTHONY COOK: Yes.
JEFFREY KAYE: How could be so big and remain a complete mystery until very recently?
ANTHONY COOK: Well, of course, comets don't become noticeable until they come close enough to the Sun that the ice in their nucleus begins to vaporize and form a glowing, uh, cloud called a coma around the nucleus. And apparently it was just bright enough that when an amateur astronomer named Yuji Hyakutake, uh, happened to be looking with his giant binoculars, he saw this glowing cloud and realized it wasn't, you know, an object that had been known before.
JEFFREY KAYE: Uh-huh. What most people think of when they think of comets is these gigantic tails, right?
ANTHONY COOK: That's right.
JEFFREY KAYE: Describe it. What's the tail made of and what are we're going to see?
ANTHONY COOK: Well, the tail is, uh, made of gas--
JEFFREY KAYE: Uh-huh.
ANTHONY COOK: --largely that comes loose from the nucleus; sunlight, uh, reacts with it and carries it, uh, away, away from the Sun. So the tail is actually streaming out opposite the direction of the Sun. Also dust gets pushed by sunlight, so you get two tails; one made of dust and one of gas. And, uh, recently, in the case of Hayakutake, we see that the tail is about 7 million miles long.
JEFFREY KAYE: That's long?
ANTHONY COOK: Yes.
JEFFREY KAYE: What's that going to appear like when we see that?
ANTHONY COOK: Well, it--assuming you're away from any kind of city lights and you're in a place where you can see the Milky Way plainly at night--in other words, a nice dark, rural sky--the, the tail will appear as a faint searchlight beam, coming out of the much brighter hazy, uh, coma.
JEFFREY KAYE: Uh-hmm. Uh, let's talk about what you have to do to see the comet. So first of all, you've got to get away from the bright lights.
ANTHONY COOK: That's right. The most basic things are to get away from the city lights and let your eyes adapt to the dark. Don't even look at a bright light for 20 minutes before you try to see the comet. Um, and another basic thing is binoculars; just ordinary, uh, binoculars like these really help a great deal in--in seeing the tail of the comet and other details within it.
JEFFREY KAYE: You can use binoculars like these? You don't need a telescope?
ANTHONY COOK: Uh, that's correct. You know, a telescope can show certain details within the comet, that a comet specialist may be interested in, but I think for a general view of the comet you can't beat ordinary binoculars.
JEFFREY KAYE: Where do you see it?
ANTHONY COOK: Well, first of all, uh, this weekend you'll want to face to the Northeast. This is a view that you'd have of the Northern sky, so if you face North, this is the horizon and the stars that you'll see above. Now on Friday night, the, uh, comet will be above the Northeastern sky, not far from the star Arcturus.
JEFFREY KAYE: How do you find the star Arcturus?
ANTHONY COOK: Okay. Now the Big Dipper actually very handy to find it, so if you find the Big Dipper, which will be more than halfway overhead--
JEFFREY KAYE: All right.
ANTHONY COOK: --looking straight North, it consists of a ball and a handle, and if you follow the curve of the handle, it automatically takes you right to Arcturus.
JEFFREY KAYE: And that's--that's the very bright star?
ANTHONY COOK: That's right. That's one of the very brightest stars in the Northern sky, and it has an orange color to it in reality.
JEFFREY KAYE: Okay.
ANTHONY COOK: Below that star, your eye might be attracted to a fuzzy cloud and that will be the coma of the comet. Then if you're in a dark enough sky you should see a faint searchlight beam going up roughly in the direction of Arcturus.
JEFFREY KAYE: Okay. And will that--and which direction will the comet be moving?
ANTHONY COOK: Okay, now the comet from night to night will be moving in the direction of the North Star. And maybe I should point out that the Big Dipper, as we learn in Scouts, uh, points towards the North Star.
JEFFREY KAYE: Right.
ANTHONY COOK: Everything in the sky seems to pivot around this. But the comet will approach the North Star night by night until Tuesday night, the 25th, it will appear only a few degrees from the North Star. And for us it will be up all night long and it will be totally invisible from the Southern Hemisphere. You're going to have to travel here to see this comet.
JEFFREY KAYE: And will the tail be as long or as bright?
ANTHONY COOK: Actually--uh, we expect the tail to be at its longest on, uh, Monday night, the 25th, when, uh, it's nearest to the Earth. And just judging from what the comet has looked like the last few nights, uh, somebody in really excellent conditions might see the tail sweep past the Big Dipper.
JEFFREY KAYE: And then what?
ANTHONY COOK: Then it continues on towards the Northeast--I'm sorry--towards the Northwest horizon.
JEFFREY KAYE: Getting smaller and smaller.
ANTHONY COOK: Getting smaller and smaller, although it's also getting closer to the Sun, so although we expect the comet to shrink and dim a little bit as it moves away from the Earth, it may then become brighter and better defined towards the end of April again.
JEFFREY KAYE: Well, thank you very much. I guess we'll hope for clear skies.
ANTHONY COOK: Yes, well, good luck seeing the comet.