Host: Scientists and space enthusiasts worldwide were wowed by the deepest pictures of our universe captured by Hubble. The first Hubble deep field was taken in 1995 and opened a whole new field of research. Hubble has since repeated the success, and the latest Hubble ultra-deep field image lets us see back in time 13 billion years, just 600 million to 800 million years after 7)The Big Bang. This was one of the first and most spectacular data sets taken with Hubble's brand new wide-field Camera Three. By studying galaxies at different epochs, astronomers can see how galaxies change over time.
Dr. J.: In November 2001, Hubble made the first direct detection of the atmosphere of a planet orbiting another star. In this case it was the sun-like star HD-209458, located about 150 light years away in the constellation of 8)Pegasus. Knowing the make-up of a planet's atmosphere allows scientists to determine whether life as we know it could conceivably exist on the alien world.
Host: By measuring bright stars that vary predictably, known as 9)cepheids, Hubble has been able to use these stars as distance markers laying a firm foundation for subsequent measurements that led to the discovery of the accelerating universe and a more precise determination of its age.
Dr. J.: Astronomers have used Hubble to observe cepheids and to pin down their distances much more accurately. These results were used as a stepping-stone to measure the distances to 10)supernovae, which in turn told us about the scale of the universe. As a result, today we know the age of the universe with much more precision than before Hubble. It is about 13.7 billion years.
Host: When we look up at the night sky it is easy to believe that space is just a giant void with some twinkling stars and a few recognizable planets. However, we must remember that there are structures and matter that we cannot see. Hubble is helping to define, in three dimensions, the distribution of ghostly and invisible dark matter in the universe.
Dr. J.: Thanks for the past twenty years, Hubble, and here's to many more.
This is Dr. J. signing off for the Hubble-cast, and wishing Hubble and all those who admire it a happy 20th anniversary.