EYE IN THE SKY

August 26, 1999
		The world's most powerful telescope, the Chandra Observatory, has relayed spectacular images of exploding stars to NASA. Terence Smith discusses the images and Chandra's mission with two experts.

Online NewsHour Special Report: One Giant Leap multimedia July 20, 1999: The 30th anniversary of Neil Armstrong's first steps on the moon. Dec. 8, 1998: An Online Q and A: The International Space Station Nov. 20, 1998: Russians send the first component of the International Space Station into orbit. Oct. 29, 1998: Tom Bearden reports on John Glenn's lift-off and the science that will be performed. Oct. 28, 1998: John Glenn, the first American man to orbit the Earth, returns to space aboard the shuttle Discovery. Oct. 28, 1998: Phil Ponce looks at the Glenn flight from an historical perspective. March 6, 1998: NASA scientist Alan Binder discusses the new discovery of water on the moon. Feb. 27, 1998: Is the universe evolving more rapidly now than it has in the past? Jan. 15, 1998: Details of Senator John Glenn's planned trip back into orbit an age 77. Dec. 31, 1997: The Hubble Telescope's clear images reach Earth. Oct. 15, 1997: NASA begins its seven year mission to explore Saturn. Oct. 2, 1997: Forty years after Sputnik first circled the Earth, historians examine its impact. Sept. 30, 1997: An interview with Mir astronauts. Browse the NewsHour's coverage of Science	SPOKESPERSON: We have booster ignition and liftoff of Columbia reaching new heights for women, X ray astronomy. SPENCER MICHELS: When the space shuttle Columbia launched safely into orbit, it was carrying not only NASA's first female shuttle commander but also the world's most powerful X-ray telescope, the Chandra X-Ray Observatory. Seven hours after launch, Air Force Colonel Eileen Collins and her crew accomplished the main objective of their mission, ejecting the Chandra and placing it in orbit eventually one third of the way to the Moon. SPOKESPERSON: Houston we have a good deploy. SPENCER MICHELS: NASA officials say Chandra's X-ray vision is so powerful it would make Superman jealous. With a combination of sensitive instruments and mirrors that reflect X-rays into the instruments that will process them, the observatory will allow scientists to study the origin, structure and evolution of the universe in greater detail than ever before. They say because of its sensitivity it can peer back ten billion years when the universe was very young. Chandra is the third in NASA's family of great observatories. The first and flagship mission of the NASA observatory program, the Hubble Space Telescope, began its orbit in 1990 -- after the space shuttle Discovery carted the $2 billion instrument to outer space. Hubble was created to help scientists see ten times further into the universe than earthbound telescopes. The images it sent back to earth - allowed scientists to see galaxies never before visible and to study black holes. Second into space the Compton Gamma Ray Observatory. The $617 million structure was launched from the space shuttle Atlantis in 1991; weighing more than 17 tons it was then the heaviest civilian spacecraft ever deployed from the shuttle. The Compton is still studying gamma rays emitted by some of the most mysterious objects in the sky. The mission's accomplishments includes the discovery of the most powerful gamma ray burst ever detected. The third and latest observatory mission, the Chandra, uses X-rays because most stars, galaxy and other space objects emit X-rays. The observatory will spend at least five years scanning the universe trying to learn the real nature of mysterious gravitational sinks called black holes and peering at galaxies, exploded stars and other bodies. Astronomers hope, among other things, to better determine the distance to various objects in the universe. At $2.89 billion -- including the shuttle ride and five years in orbital operations-- it is one of NASA's most expensive robotic projects to date. Still to come, as long as Congress funds it, an infrared telescope to be launched in 2001.
	X-ray astronomy
	TERENCE SMITH: With me is NASA's chief scientist for the Chandra X-Ray Observatory Project, Martin Weisskopf. Joining us a member of the astrophysics community, Doctor Robert Kirshner and Professor of Astronomy at Harvard University. Gentlemen, welcome to you both. You've been working on this project - the Chandra project for a long time -- 22 years, and now you have some payoff. Tell us what it is and how you feel about it. DR. MARTIN WEISSKOPF, Chief Scientist, Chandra Project: Well, the payoff which is spectacular is that after all these years of hard work by so many thousands of people, scientists, but also engineers, managers, technicians, we see the fruits of our labors and a few weeks ago the shuttle brought other pay load into orbit as you saw on the lead-in and now after several weeks of operation, we have the first X-ray images from this observatory and believe me, we are so excited about what we're seeing and very glad to share it with you. TERENCE SMITH: Dr. Kirshner, maybe you can put it in perspective -- the whole project and the immediate results. DR. ROBERT KIRSHNER, Harvard University: Well, X-ray Astronomy allows us a new window on the universe. X-rays are emitted by objects that are extremely hot. So places where stars are exploding, places where gas is swirling into a black hole, places where there is gas that is trapped in the gravitational grip of a huge cluster of galaxies, those are the places that we see with X-ray Astronomy, and Chandra is the most powerful X-ray observatory ever. It is made with an exquisite system that images the light. It makes very sharp images, and that has been a tremendous breakthrough in X-ray Astronomy.
	Out of this world images
	TERENCE SMITH: Let me ask to you look at some of the images that have come back from this telescope and tell us what we're seeing. Here is the first. DR. MARTIN WEISSKOPF: Well, that image that we're taking a look at is not a visible lighting that we could normally see with our eyes. This is an image taken with this X-ray telescope of a region of space where 300 years ago a star exploded. That star exploded and spewed forth material that went into the interstellar medium that is the region around the star and heated it up to incredibly high temperatures. In this image what you are seeing is the intensity, the very bright spots are the brightest in the X-rays, and the redder spots are not so bright and the darker spots are not so bright at all. And, as my 91-year-old uncle said, there are incredible things to be seen there. He looked at the dot in the middle and said, "What is that?" And that's a darn good question: What is it? That is one of the questions we're going to study and it may be the remains of the central part of the star that exploded. TERENCE SMITH: Doctor Kirshner, we're looking at a piece of history there? DR. ROBERT KIRSHNER: Yes, that is something that exploded about 380 years ago, and the way we know that is that we can see that this has been expanding. That object has been detected in the radio; it's been detected in the optical, but in those wave bands you don't see most of the star. It's only in the X-rays where you get to see most of the mass of the exploded star -- shreds of it which are moving out at more than ten million miles an hour which get heated to very high temperatures, a thousand times hotter than the Sun by the collisions of this stuff with the surrounding mediums. The interesting thing is those stars are supposed to explode by means of gravitational collapse. That is the center of the star crunches down under the force of gravity, it becomes a very dense thing which has the mass of a star but the size of a city, a neutron star. Well, we have had optical pictures of Cas A and we've had - TERENCE SMITH: Which one of these. DR. ROBERT KIRSHNER: Right. And we have had X-ray images before, but nobody had seen that little dot that is in the middle that probably is the neutron star, the real remnant of the star that collapsed. TERENCE SMITH: The actual star itself. Let's take a look at the next image now and we'll see whether you can see a great deal more here.
	Exploding stars
	DR. MARTIN WEISSKOPF: This an X-ray comparison. In a little while we'll see a opti-visible light but the picture on the right is the previous best X-ray telescope and the picture on the left is the Chandra image; the Chandra image was taken in about an hour and a half of observing and the one on the right was taken in three days. And you can just see the remarkable clarity and advances that are made by this wonderful telescope. For example that point object in the middle you couldn't find in the observatory previous work and the Chandra itself will do much, much more. TERENCE SMITH: All right. And we have yet another one which has come back. Tell us about this. DR. ROBERT KIRSHNER: Well, this is a comparison of optical data shown on the right with the X-ray data on the left. Optical light comes from stars. And you can see the field is studded with stars. The Cas A remnant is in the plain of our Milky Way Galaxy. On the left you see the X-ray image and there aren't all those point sources, because stars - even though you think of them as very hot -- are too cold to emit much X-ray light. But the very hot gas that is in that volume of the remnant is emitting in the X-rays. That's what we see. And you can even tell from the optical data and especially in the near future from the X-ray data what that is made of. It turns out it's made of elements that are heavier than the hydrogen and helium that make up most of the universe. That stuff is made up of oxygen and the products of nuclear fusion of oxygen - silicon, sulfur, calcium, all the way up to iron. And it is literally the case that calcium that is in your bones, the oxygen that's in the air you're breathing, the iron that's in your blood came from exploded stars that went off before the Sun and the Earth formed. So we're really seeing where we came from when we look at a picture like that. TERENCE SMITH: And that is the significance, Doctor Weisskopf, the origins of the universe? DR. MARTIN WEISSKOPF: Well, that is certainly the story begins of planets, of stars, and the spreading of heavier material throughout the universe -- that is one of the significance's. As we start to look at other objects, we will be looking at the hot matter that is every where in the universe. Regions that we haven't shown in this image will start to come out, and we will do searches for dark matter. Studies of some normal stars that do emit X-rays, which are very fascinating, and trying to answer questions as to how do super massive black holes that are supposed to be at the center of galaxies -excuse me - that are at the center of galaxies how they can possibly produce huge jets of emission- - numerous questions that I know will not only interest astronomers but also the young people in the county to start looking at these scientific questions and seeing what implications they have. TERENCE SMITH: What implications could they have? What could they teach us? DR. ROBERT KIRSHNER: Well, I think the big picture is the universe has gotten more complex overtime. We think that the universe began in a hot, dense, Big Bang maybe 15 billion years ago -- then the elements that were present were just hydrogen and helium that cooked in the Big Bang. And everything else that you see around you is the results of something happening -- of stars cooking, the light elements into the heavy ones. So we really are made of stardust. We really came from that whole set of processes. Many things have changed in the universe over the last 15 billion years but one of the threads is that matter has evolved to become more complex, more interesting and to have more possibilities.
	Drawing energy from space
	TERENCE SMITH: Dr. Weisskopf, the possibility I believe exists what we could draw energy from some of this -- from quasars which you also see on -- through this telescope. DR. MARTIN WEISSKOPF: Well, I think perhaps that is speculating a bit but it's certainly true trying to understand the mechanisms that produce these enormous amounts of energy ultimately has of course the end conclusion that we'll understand our physics better and perhaps be able to make use of such knowledge in harnessing energy for ourselves. This may be in ten years, it may be in twenty years, it may be in a thousand years. DR. ROBERT KIRSHNER: I think that is a little far fetched. I think that is a kind of science that you don't have to justify in practical terms or you shouldn't try to justify it in practical terms because it really isn't a practical sort of thing. This is the science of exploration and we're not claiming that we're going to make a better cell phone although making the technology for the satellite is a fantastic push on what is possible. We're not claiming that we're going to make you live forever -- even though, you know, we would all like to live a long time. This is about nourishing another part of your humanity, of your person. It's about satisfying your curiosity. And I think we are incredibly lucky that we get to do this for a living, and that it is also something that ha a very broad resonance with I think lots of people, with kids and with a broad range of people who are interested in the question of how the world got to be the way it is. And by looking at it and developing these techniques we're actually measure it, we're taking that from the realm of legend into a kind of experimental science where we can really take a look and see how things happen. TERENCE SMITH: To a brave new world. A final thought. For you -- after all these years working on it, and your colleagues, tell me it must have been an exciting moment when the first images came back and you knew it was working. DR. MARTIN WEISSKOPF: Yes, we knew it was working immediately from the first few -- we count as single X-rays we call them photons and from the first 20 or 30 that came into the telescope we knew that everything was working as well if not better than we thought. TERENCE SMITH: Did you cheer? DR. MARTIN WEISSKOPF: We cheered and the moment was tremendously exciting and it still is exciting. I find myself grinning all the time. I'm not quite sure I believe it yet having worked on it so long but it's just wonderful. And we hope that things continue to go smoothly as they have thus far. It's not always easy up there as we know. TERENCE SMITH: Dr. Kirshner, thank you very much, Dr. Weisskopf, appreciate both of you coming in.