Two days after his triumphant announcement of the Explorer satellite’s dramatic findings, astrophysicist George Smoot talked for several hours with Maclean’s Washington Correspondent Hilary Mackenzie. During the conversation in Smoot’s house near Greenbelt, Md., Smoot discussed the significance of his team ’s discovery and how it was achieved. Excerpts:
On why the findings are important to nonscientists: Everyone feels the need to know where they came from and who they are. Every culture has had myths about how the world began. In modern times, we are very technological and we have our scientific version. And it turns out that science’s version is more incredible than any myth anyone ever made.
On the Big Bang theory: Twenty-eight years ago, with the discovery of the relic radiation from the Big Bang, the theory suddenly vaulted into the forefront of science’s explanation of the origin of the universe. The theory says that the universe started from conditions that were extremely hot and extremely dense. The big mystery was that when we observe the universe, we see all these [stars and galaxies] that are clumps of matter with empty regions between them. Up until now, when we looked at the relic radiation from the Big Bang, which gives us a picture of what the universe looked like 300,000 years after the Big Bang, or 15 billion years ago, when the universe was very new, it was uniform. So there was this paradox: you can say that you have a very smooth beginning and you have a highly un-smooth present, and how did the universe make that transition?
On the searching for the origins of the universe: We measured the background radiation with radio receivers and we measured the amount of power coming in from all parts of the sky. That radiation has been travelling to us for 15 billion years. We know that after the Big Bang, there was a transition of matter. Instead of being gas or liquid, it turned into plasma, and suddenly it becomes opaque like a fog. The universe was like being in a morning fog as it expanded. Then it cooled down and became transparent. Light has been travelling to us from the edge of the fogbank for 15 billion years, and we are looking back 15 billion years—almost to zero. That’s how we know that we are measuring what things looked like at that time.
On what the satellite finding showed: We
thought there had to be ripples. That is what I have been working to try to find for 15 years— to find those ripples. The ripples become changed variations in matter, and those are the seeds that were going to clump the matter together and make it cooler so stars and galaxies formed, and the primordial material condensed into planets. We expected to find the ripples on a much bigger level, and that is why there is one more missing piece. If they are as small [as the satellite data indicated], there must be this invisible matter in the universe,
not like the material you and I are made out of, but matter that doesn’t interact with light. It is invisible and the only way that you can see it is by its footprint, like an invisible man that walks across a carpet. You can see a footprint and how much he sinks in, and you can tell how heavy he is. And that’s what we are seeing. We are seeing the footprints of the invisible matter of the universe.
On what caused the ripples: Whatever caused the rapid expansion of the universe following the Big Bang—the same forces
caused the tiny ripples. Because if you try to do something too fast, you shake a little. God might be the designer.
On his team’s work: For 15 years, we thought about how to do the experiments. We had to worry about the moon, the galaxies— anything that could produce a signal. When you are looking back in history, you have to look past everything that ever happened. Then we had to make receivers. We spent three or four years putting them together, testing them. Then we had to take data for over a year, until we finally had enough data points. Then we had 360 million data points and we had to process it very carefully. If only a tiny fraction of the data was wrong, there would be a mistake. So most of the past year we spent checking that we had done everything right, trying to account for everything and putting everything together in this giant jigsaw puzzle.
On how the findings could be used: People speculate that if we can understand how the universe began, we might be able to make our own universe. It’s scary. You just have to get a tiny part of space into the same conditions as our original universe and then it happens automatically. That is what is so wonderful about this theory. Whoosh, and you have the whole universe.
On himself: I have a strong personality. I don’t personally think of myself as having a giant ego. I am intense and adventurous. I always want projects to do. I don’t mind if I have to struggle. When I got to Lawrence Berkeley Laboratory, there were six Nobel Prize winners, and some of them had fire in their bellies. I never felt that I had quite that same fire, but maybe I do. What drove me for the last three months was that I wanted to know the answer. I know the secret of the universe. I have the key. □
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