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NASA at the Nobels
Hi, this is Ed Goldstein with NASA Public Affairs. This week, the entire NASA family shared a special pride in the award to John C. Mather of the 2006 Nobel Prize in Physics.
Mather, a senior project scientist at NASA's Goddard Space Flight Center, was honored for his work on the Cosmic Background Explorer Satellite, or COBE. This satellite, launched in 1989, helped to validate the Big Bang Theory. Professor George Smoot of the University of California at Berkeley, who also worked on the COBE project, was co-recipient of the Nobel Award.
I was among a number of folks who shared in the excitement of Nobel Week in Stockholm, including Mather's science lecture in the Aula Magna at Stockholm University.
Dr. Mather began his remarks by musing on the special nature of astronomy.
I am delighted to be here of course to tell you the story of the universe, the story of how we found out about it…First I wanted to explain about how it is astronomers know about the universe. You will say, "How can you know about the early universe when you’re not there?" The answer is you can look back in time by looking at things that are very far away. Light travels very rapidly, but the speed is not infinity. So when you look at your hand you see it as it was three nano-seconds ago. When you look at the sun you see it as it was 500 seconds ago. If you look at the middle of our galaxy it's as it was 25,000 years ago. And if you look to the most distant things we can see ….we know how they were about 15 billion years ago. Our current number is 13.7 billion (years). So far away you can look back in time. It's a little bit like geologists looking at old rocks. So ours is done with a different thinking.
He then spoke about the revolution in our understanding of the universe prompted by 20th century ground-based observations.
Back in 1929 when the worldwide economy collapsed, we also discovered that the universe is expanding. This is Edwin Hubble's plot from 1929 and if you divide the distance that he estimated by the velocity you can determine the apparent age of the universe. And the remarkable thing about his plot is that all of the objects that he measured seem to be consistent with a single age for the universe…. The velocity is proportional to the distance. A very astonishing conclusion that can be drawn from this is that there’s no apparent center or edge of the universe. No direction is preferred over any other direction. And we calculate that no particular observer is privileged either. So even though it looks like the entire universe is receding from us we calculate that an astronomer on another planet around another star far from here us would calculate that he or she were at the center of the universe. The conclusion is none of us are at the center of the universe. So maybe the universe is even infinite in size.
Mather, who was present at the creation of the COBE project, discussed how the satellite operated and its science aims.
This bird (COBE) was 900 kilometers above the Earth, orbiting above the Earth from what is called a polar orbit, so it was orbiting over the sun day-time, night-time boundary over the Earth and that’s a place where we were able to keep the sun out of the apparatus at the top and shining on the solar panels from the side all the time. So it was a lovely orbit, and we were fortunate nature gave us this possibility.
Now I'll show you the apparatus that we used to measure the far infrared spectrum of the Big Bang radiation … The prediction of the Big Bang radiation was that it basically was an equilibrium form of radiation which leads to a very unique spectrum prediction, which there’s only one number that’s is adjustable, that is the temperature. So our idea here is we will make a perfect simulator of the Big Bang. Have it adjustable in temperature, so that when you put this device into the antenna and replace the sky, if you get the same answer then the sky has the same spectrum as the calibrator. So that was our strategy and we were able to do it extremely well. That's how it was that even only a few weeks after the launch we were able to immediately draw the chart that people were so proud of.
In summarizing COBE's science findings, Mather focused on its role in validating the Big Bang Theory.
The other thing that people cared a tremendous amount about was how the Big Bang story seems be the right story. Had this not been true people would have been extremely worried. There were other theories people had in mind. There was something called the Steady State theory which was popular until the discovery of the background radiation itself. When the big background radiation was discovered people still felt well maybe there’s a way that a steady state universe which is continually being replenished with the creation of new matter might have still been able to generate the cosmic microwave background radiation. But what it couldn’t do easily was explain why that radiation would have such a perfect spectrum of the Big Bang that we have. Because complicated astronomy hardly ever produces simple results.
Turning to the future, Mather now the Senior Project Scientist for the James Webb Space Telescope, set to launch in 2013, spoke about the bold goals of this successor to the Hubble Space Telescope.
There are four main things we think scientists will use this observatory for. One is to pursue discoveries of the distant universe. We now have what we believe is an accurate picture of the content of the early universe. We have dark matter, dark energy which causes the universe to accelerate the expansion, and ordinary matter…. We now claim that we should be able to calculate how everything turned into stars and galaxies. So we want to go see if any of that is true. So we will take pictures of the early universe, identify the little fuzzy specs that seem to be from those most distant parts and analyze the heck out of them. We'd like to see how galaxies like our own were formed, because we have the opinion that galaxies were formed from small parts that have joined together to make big parts. If this is true we should be able to see that the early galaxies are quite different from modern galaxies. We would like to be able to see stars being born … There are a few nearby stars where we have already observed that there are dust clouds orbiting around them and we calculate that there could be planets there. This particular cloud, for instance, has a ring shape that you can quite clearly see in the picture. That ring shape probably occurs because there’s a planet organizing the gravitational forces here to make a ring. So if this is true we should even know roughly where to find such a planet in this picture. So large planets like Jupiter sized could be detected directly by this new observatory. So there’s a tremendous amount that’s in our future for observation of the early universe and for checking out our entire history of how we got here.
Following Mather’s talk, I asked Professor Per Carlson, Chairman of the Nobel Committee for Physics, to explain the importance of the 2006 prize.
This year's Nobel Prize changed the direction of cosmology. Earlier cosmology was something more like speculations; some people say it was theology. But with the COBE satellite a new ground was broken, a new way was found for cosmology that become a precision science, that is a science where you really measure things and give accurate numbers. And the FIRAS instrument that John Mather was a principal investigator on they measured the temperature of the microwave background radiation with a precision that was never done before. And also they showed this microwave background radiation had a black body form which implies that it came from a state of equilibrium which is a characteristic of the early universe. So it really is a strong support for the Big Bang scenario. So that’s why it is so important. So it somehow changed our view of the universe.
During Nobel Week there was also great excitement among the Swedish people about the mission of the Space Shuttle Discovery, whose crew includes Sweden’s first astronaut, Christer Fugelsang. Prior to Discovery’s lift-off, I spoke with a lady named Angela about the anticipation building for the Shuttle mission.
I think it's very exciting for the Swedish people, because we are a very small country. It's nine million people. It's not that often one person makes a difference international-wise. That’s why it’s so exciting … There’s been a big media information about him. A countdown on the television every morning as to the possibility of (the launch) at three o’clock at the morning and also they had a service to wake you up. If you set SMS to the SVT they make a phone call and wake you up in the morning so you can actually watch the take off. So that’s pretty big.
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