December 31, 1997
With its troubled past long behind it, the Hubble Telescope produces dazzling images.
ELIZABETH FARNSWORTH: The Hubble Telescope, which went into space in 1990, produced its most detailed images ever this year, and they came from the ends of the universe. To tell us about them we turn to Anne Kinney, an astronomer with the Hubble program. She's also a visiting professor at Johns Hopkins University in Baltimore. Thanks for being with us. Where is the Hubble now and who decides what it looks at?
ANNE KINNEY, Space Telescope Science Institute: Well, the Hubble's in orbit. It's about 350 miles up and at the beginning of the year, when we did a refurbishment mission, it got a little boost because the orbit degrades. So where it ends right this moment would be hard to tell you because it rotates around the Earth every 90 minutes.
ELIZABETH FARNSWORTH: And the refurbishment mission was when you fixed some things on the lenses, right?
ANNE KINNEY: No. In this case we weren't fixing; we were replacing with newer instruments that had more capabilities and new wave bands.
ELIZABETH FARNSWORTH: Amazing pictures came out this year. What did you learn from those pictures that you didn't know before?
ANNE KINNEY: Well, we learned some things about the galaxies when they collide, which is very important to us because in the early universe we think it was a very common incident for galaxies to collide. Now that the universe has expanded galaxies are farther apart.
ELIZABETH FARNSWORTH: Okay. Let's put up the first colliding galaxy picture. What are we seeing in this picture?
ANNE KINNEY: This is the antenna galaxy, and the blue blotches that you see are actually star-forming regions that are very massive. In this galaxy we detected about a thousand galaxies. This was done by Brad Whitmore and Francoise Schweitzer.
ELIZABETH FARNSWORTH: Okay. Wait. Let's back up a minute while we're looking at this picture. Tell us what a galaxy is and tell us where this is, how far out it is.
ANNE KINNEY: This is about 63 million light years away. So in terms of the entire universe, you'd call it fairly local.
ELIZABETH FARNSWORTH: Because the universe is that huge.
ANNE KINNEY: Yes. The whole universe would go back about 14 billion light years. And so this object gives us an opportunity to see a galaxy colliding nearby us, so we can really see the mechanisms at work as something collides.
ELIZABETH FARNSWORTH: And what is a galaxy?
ANNE KINNEY: A galaxy is a conglomerate of about 100 billion stars.
ELIZABETH FARNSWORTH: Like our own Milky Way.
ANNE KINNEY: Like our own Milky Way. And these two that were colliding were spiral galaxies like our Milky Way, which--
ELIZABETH FARNSWORTH: We have another picture. Let's look at the second colliding galaxy picture.
ANNE KINNEY: That will give you the real picture of what's going on. There you can still see the two bodies that formed together to make sort of a heart shape, and you can see the tails as they went together. They're probably on their first path right now.
ELIZABETH FARNSWORTH: When you say collide, do you mean literally collide, these are galaxies that are running into each other in space?
ANNE KINNEY: I mean literally collide, and they not only run into each other, in a case like this they are probably what you're going to end up, which is one galaxy, not two.
ELIZABETH FARNSWORTH: When did this happen? If these are so many million light years away, this happened that many million years ago, right?
ANNE KINNEY: Sixty-three million years ago, yes. That's how long it took the light to get to us. And so 63 million years ago they were in that first path in their collision. Now they're probably already emerged into an elliptical galaxy, a fairly homogenous, settled galaxy.
ELIZABETH FARNSWORTH: Now, we have an artist's concept of what it would be like if our own galaxy collided. Let's look at that. Tell us what we're seeing here.
ANNE KINNEY: Well, if Andromeda, which is our sister galaxy, collided with our own galaxy, this is what it would look like. It would contort as it approached us. There would be a lot of star formations. It would go through a period where it settles, and then in the end, you'd end up with an elliptical galaxy, fairly homogeneous galaxy that would look something like this.
ELIZABETH FARNSWORTH: And is this important because this is the way galaxies form, this is--you're seeing what happened that made the universe?
ANNE KINNEY: We're trying to understand the way galaxies form, and mergers are very important in that process.
ELIZABETH FARNSWORTH: Okay. We have another picture called planetary nebula. Let's look at that. And tell us what we're seeing here.
ANNE KINNEY: Now, we're looking at something truly local. This is within our Milky Way. This would be about 2,000 light years away. So it's really close by. This is the very late stages of a star's life, and--
ELIZABETH FARNSWORTH: Let me interrupt you. So it's not really a planetary nebula. That's some kind of misnomer?
ANNE KINNEY: Yes. They were named planetaries because the first ones to be seen were spherical, and they looked like planets, even though astronomers knew they weren't. What Hubble has started to see is that the planetaries have an enormous range of behavior and look very different from one to the other. This one probably got its pinch in the center because of a close companion that forces the thing to not be able to expand around the center so that all the gas that gets expelled is expelled along those two axis.
ELIZABETH FARNSWORTH: So this is the Hubble seeing--is it a star expanding--the gases expanding against some sort of another object?
ANNE KINNEY: In the late stages of a star what happens is that the star does expand for 1/2 billion years. It gets very large, and then eventually the surface of the star gets exposed, and it expands very rapidly. And when the surface is exposed, it also gets very hot, very bright, and it lights up, so you get to see the gases that have been expelled over the years.
ELIZABETH FARNSWORTH: And those beautiful colors are the way it looks?
ANNE KINNEY: They're very close to the way it looks. These were taken in narrow band images and put together, so they are not exactly the way our eye would see them. The colliding galaxies were almost exactly--they were natural color. They were very, very close to the way we would see them.
ELIZABETH FARNSWORTH: Now, we have detail from the planetary nebula. Let's look at that.
ANNE KINNEY: So this is another planetary that is thought to have a very close companion, Hubble 5. It's called--again, the companion was probably pinching the thing in the center so that when the gases expand, they expand in a double bubble type formation. That's why you see it as a butterfly type formation.
ELIZABETH FARNSWORTH: And what does it mean, what we're seeing here, for the way that our own planet was formed, or that we're formed?
ANNE KINNEY: Well, we have another planetary image that we can look at--the lemon slice--that is our best guess for how our planet will look 6 billion years from now when it becomes a planetary nebula. We think that our planet will be a spherical planetary nebula because we don't have anything like a massive companion that would limit the expansion in one direction.
ELIZABETH FARNSWORTH: What we're seeing now is--
ANNE KINNEY: What we're seeing here is a double--you see, there's sort of a double shell. The outer shell is the slow wind; the inner shell is the very fast wind, as the star exposes its inner layers to become bright and then illuminate the gases that it's been expelling.
ELIZABETH FARNSWORTH: When these things happen to the stars, they throw carbon and all sorts of materials into space, right? Is that the carbon that helps make us up?
ANNE KINNEY: Yes, absolutely. And, in fact, it is stars of our mass, mass like our sun, that put carbon back into the galaxy. That does not happen with the more massive stars. They put in--the really massive stars put in iron, which is in our blood, and oxygen, which we also need. But for carbon it's the lower mass stars like our sun that expel into the local medium and then collapse into the next phase of star formation.
ELIZABETH FARNSWORTH: So the Hubble is looking at something so far away that it's what we're made up of too.
ANNE KINNEY: Yes.
ELIZABETH FARNSWORTH: Interesting. Thank you very much.