Light travels fast, but it doesn't reach you instantly. So when you look up at the stars at night, you're not seeing them as they are at this instant, but how they were when the light first left. We'll talk with Dr. Robert Osserman about peering back in time - after this on Earth and Sky.
DB: This is Earth and Sky, on the limits of looking out in space - and back in time. We spoke with Dr. Robert Osserman of Berkeley's Mathematical Sciences Research Institute:
(Tape 0:08:24-0:08:34) If we go out at night and just look out in space in all directions, and we -- ever since Galileo we not only look with our eyes, we look with telescopes -- (Tape 0:08:48-0:09:44) and bearing in my mind that it is always the radiation we are getting, the light and radio waves and infrared waves that we're getting, and they travel at the speed of light -- everything we see, the further away it is, the further back in time we're seeing it. So what we are really seeing when we look out is something I like to call the "retroverse," which is everything that's out there, looking back in time and out in space, which are equivalent things. And we discover you can only look back so far, you come to a certain point which we call the "cosmic microwave background radiation" beyond which, that is to say, further away or further back in time, the universe was such that no radiation escaped. And we will never get to see that.
DB: Thanks to Dr. Robert Osserman of the Mathematical Sciences Research Institute for speaking with us. And with thanks to the National Science Foundation, I'm Deborah Byrd, for Joel Block, for Earth and Sky.
Author: Beverly Wachtel
Thanks to the following individual for aiding in the preparation of this script:
Dr. Robert Osserman
Mathematical Sciences Research Institute
If you enjoyed this program, you may be interested in the following:
Poetry of the Universe, by Robert Osserman. NY: Anchor/Doubleday, 1996.
Mathematical Sciences Research Institute website: