UniverseOurGoldenAgeOfAstronomyTheCOPYRIGHT

[music] Hallelujah. [music] [music] >> [music] >> The space age has thrust us into the golden age of astronomy. As we walked on the moon, sent probes to other planets, lofted satellites [music] and rockets with radio and X-ray equipment into space, we have begun to see the universe in ways never imagined. We have come away with a [music] stunning new perception of it. Perhaps the most dramatic revolution in our understanding since the time of Galileo. And I think that [music] starting from radio astronomy and then going to X-ray astronomy which has to be done from space and gam astronomy which has to be done from space. We now have a completely different view of the universe. The universe is a place where there are gigantic explosions uh in very short times. We see a star brighten up like a thousand suns and then go away in the time it takes you to draw a breath. uh we look back at the origin of the universe, we see an enormous explosion. We now believe that that was the beginning of the universe. So we find a universe which is very active. Stars are born, star die, star explodes, uh galaxies explodes, the universe is an explosion. As we probe space, a new and violent universe has begun to emerge. A universe of supernova, black holes, quazars, and pulsars. Our instruments attached to rockets have for the first time lifted us beyond Earth's atmosphere to reveal its secrets and to confront us with perhaps even greater mysteries. For centuries, we have searched the skies [music] with every tool available to answer some of the most simple, some of the most profound questions. Were we alone in the universe? How did we [music] come to be? How had the stars been created, the universe, our solar system, the planets? What were they like now? It was not until Galileo invented the telescope in the early 1600s [music] that people could begin to formulate the most basic hypothesis. Using his telescope, Galileo was able to see that the moon had craters, Jupiter, a massive red spot [music] in four planetized moons. The excitement this caused was extraordinary. [music] And during the next 350 years, man built ever larger, more sensitive telescopes in hopes of seeing more. The basic limitations, however, of being Earthbound remained until the advent of the space age. The marriage between space and astronomy was a natural. The problem for earthbound astronomers, even those using the most powerful telescopes, was that the atmosphere distorts our vision. It's as though one were looking up from the bottom of a lake to try and see the stars. In addition, most of the matter in the cosmos is utterly dark. It can't be seen with an optical or light sensitive telescope. It was in this realm, the realm of the invisible universe, that a number of astonishing breakthroughs would be made. Our first attempts to probe into our invisible universe by actually rising above the atmosphere were conducted in 1946 using captured German rockets with pinhole cameras. Astronomers on the ground continued to try by tuning into radio waves that could penetrate the atmosphere, which sounded something like this. To listen to the heavens if they couldn't see it. One day in 1967, two British radio astronomers were startled by a potentially momentous sound that began to come across their receivers. They began to hear a source of radio waves that exhibited extremely regular pulsations. This object beeped on and off with the precision of a clock that loses only 1 second in a million years. They named the source of the radio waves only half jokingly the little green men. The little green men in fact turned out to be a pulsar, a star beeping on and off. But it was here in radio astronomy that we started to hear the very beginning of the universe itself. The universe is filled with a faint whisper of radio waves discovered in 1965. This radiation we think was emitted when the universe was about a million years old. Steven Weineberg is the Nobel Prize winner who wrote the first three minutes. >> These radio waves seem to be coming with the same intensity from all directions. And that indicates to us that at that time when this radioatic was produced. Uh the universe didn't consist of stars and galaxies and clusters of galaxies. It was just a uniform pretty featureless gas of hydrogen and helium without any of the ordinary things we see in the sky, stars or galaxies. Certainly no astronomers. >> But what had happened then? What in fact existed now? It was a beginning. The astronomers tried desperately to search the skies for more relics of this unknown, eerie past. The radio astronomers were picking up the sounds of radiation of objects in the sky. This radiation was also present in the form of light, x-rays, and ultraviolet rays. All were blocked by the atmosphere. Lifted by rockets and balloons, men sent exploratory instruments into space. When space technology finally advanced to the point that we could send satellites equipped with X-ray devices aloft, the revolution began. [music] NASA sent up an orbiting astronomical observatory known as OAO1. They followed it with its successor, OAO2, which orbited the Earth 22,000 times, sending back thousands of astronomical observations. Skyab and other vehicles went aloft for more images. And for the first time ever, man began to receive back from space images of the stars, the galaxies, our own sun. Without question though, the launching of explorer satellite Uhuru was one of the major milestones. Ricardo Gioone was one of the project managers. The Huru was um a dream that um some of us had since uh was 63. We had seen the first indication that there were X-ray stars in the sky in ' 62. And it became immediately obvious that we needed more time to observe what was going on and more precision in finding out where the stars actually were in the skies. By the end of the Uh-huh mission, a new map of the heavens would be drawn. We began to find stars we had never seen, discover stars in disguise, and watch closely for the first time their dance of death and creation that in fact became the seeds of life throughout the universe. We were able to confirm our understanding that the stars shining in the sky in fact only shown for a portion of their life. They then began to deplete the energy burning in their cores. When that happened, they would start to collapse under their own gravitation. As their shell pressed upon the core, it released vast [music] amounts of energy that expanded the star until it became a red giant. The temperature would rise to an extraordinary degree, perhaps a billion degrees or more within a fraction of a second. The heat would instantly convert the simpler, lighter elements which made up the star into the heavier elements needed to form life. Its [music] fate then depended on how massive the star was. If it were greater than our sun, it might [music] end in a spectacular explosion called a supernova, spewing forth the elements of life. The discovery via X-ray astronomy that these elements for life were being formed right now elsewhere in the universe was a profound one. The Einstein X-ray Observatory was about to come back with another profound one. It was the Einstein that returned with the awesome revelation of the phenomena known as black holes. >> Apparently there are galaxies where at their very centers there is a black hole present for some reason we don't understand. And this black hole is in an extremely massive dense body. So dense that the gravitational field will not allow light to escape from the black hole. But that when matter gets in the vicinity of the black hole, it's inexraably put into a very tight orbit around it and heated to a very very high temperature so that uh it gives off X-rays. And we can't see those X-rays from the surface of the ground. We can see them with telescopes in space such as the Einstein X-ray Observatory. The phenomenon of black holes was not only an astounding phenomenon of itself for astronomers to ponder. It led them to the startling possibility that our universe might in fact be one of many universes. The whole question of black holes of course is uh very difficult to understand for u scientists let alone non-scientists because it involves space curling up on itself in a strange way. But there are models of the universe that suggest that there may be other universes that are not directly observable but are connected to us by what are called wormholes. These are regions of space and time that have curled around in such a way that they lead from one universe to the other. Now, how would we see this connection, this wormhole? To us, it might appear as a black hole, a region into which if you drop anything, it disappears from our universe, but in the other universe, it might appear as what is called a white hole. a region out of which mysteriously things emerge almost as if from nowhere. >> There may be many such wormholes connecting a multitude of different universes. As we began to understand supernova, black holes, and to identify mass in the universe, we began to draw a picture of how the very universe itself formed. The astronomers called it the big bang. We can trace the history of the universe back to a time when the temperature was about a million billion degrees when the universe was perhaps a 10 billionth of a second old. Uh at that time the expansion of the universe had barely begun and the whole universe that we can now see with the largest telescopes a sphere of about 10 billion light years across at that time was no more than about a few centimeters in radius. Uh the universe starting at that moment expanded and cooled. Nuclear reactions were going on all the time. For the universe, it was still too hot for ordinary atoms to hold together. I think the universe was just a smooth soup of [music] nuclei and electrons. Eventually, when it got to a few hundred thousand [music] years old, maybe a million years old, the temperature dropped to a few thousand degrees, perhaps half the temperature of the surface of the sun. At that time, for the first moment, [music] it was possible for atoms to hold together. It became possible for gravitation to start clumping the matter into galaxies, [music] clusters of galaxies, eventually into stars. Uh so the all the structure we see in the sky, the clusters of galaxies, the galaxies, [music] the stars could have first began to form when the universe was about a million years old. Our knowledge about the galaxies and the spaces between them has advanced tremendously. But it seems for each new advance a new mystery appears. One of the things that astronomers are at a loss to explain right now is the matter between the galaxies, the quote missing matter. >> We really don't like the name missing matter anymore because the matter isn't missing. It's the light that's missing. So we we've gone to dark matter or non luminous matter. But it really looks like probably 90% of the mass in the universe is not radiating. It's just not the kind of matter that we see in normal stars. And so, in a sense, this is this is a joke. This is a joke for astronomers because we became astronomers thinking we were going to study this this glorious universe and now we find out we're only studying five or 10% of the universe. physicists are now getting into the act and they're trying to study from their um particle physics what these other non- luminous things could be. >> So the question is what is the dark matter? >> That's right. That's right. And at the present time the only answer is we really don't know. It could be any of of a number of things. It could be very faint stars. Uh, in which case our models of stellar evolution would have to be changed because we've made models based on what we could see. We didn't think there were stars that were much fainter than a tenth of the of the mass of the sun. Um, it could be it could be rocks. It could be coal rocks. It could be planets of the size of Jupiter which we just can't detect. But you would need enormous numbers of these things. It could be little black holes. It could be massive black holes. It could be a whole new zoo of particle physics. Nutrinos, axons, the the list is endless. Many of these particles have never been observed. We don't even know that they exist. But we can attribute we can attribute properties to them which would just do what we know this dark matter has to do. I think there's no longer any doubt in most people's minds, most astronomers minds, that this dark matter really exists. Uh the problem is what it is. >> As speculative as these theories are, advanced astronomical instruments may well find the clues to the answers. The great [music] hope is that in some of the things that the theoretical physicist thinks may have happened at the very near the very beginning of the universe could have left some [music] kind of relic that would be present in the universe that we see today. And you can find in the physics [music] literature uh speculations quite intriguing, very mathematically ingenious, may even be true about periods of inflation and when the whole universe that is now visible grew out of a single infinite decimal quantum fluctuation. [music] Or maybe even more strange when there was a phase transition like the melting of ice but in which the number of dimensions of [music] space dropped from some large number. The most popular [music] value is nine down to what we now know as the three dimensions of ordinary space. Um, of course we can't look back at those [music] early times and our best hope is that the processes that were going on then left some sort of relic, some sort of fossil that astronomers might be able [music] to find in the universe today. [music] >> [music] >> What is clear is that space exploration is opening up the universe for us to see, to understand in ways never even dreamed of before. [music] And today, the US, the Soviets, the Japanese, and the Europeans are eagerly exploring it with ever more fascinating questions. There was however another world that space exploration opened up almost by accident. Perhaps TS Elliott guessed it when he wrote, "We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time. [music] >> [music] [music] [music]