Guest: Dr. J. Richard Gott. Topics: Cosmology, Mars colonization & the Copernican Principle, time travel possibilities. Please note that you are invited to comment, ask questions, and rate this program on the new Space Show blog, http://thespaceshow.wordpress.com. We welcomed Dr. J. Richard Gott to this two hour plus program. Dr. Gott's book, "Sizing Up the Universe: The Cosmos in Perspective," is available on the OGLF book page at http://www.amazon.com/dp/1426206518?tag=onegialeafou-20. This book will be make a great holiday gift so do consider it. Remember, if you buy it from the OGLF Amazon link above, Amazon makes a contribution to The Space Show. In addition, you can read an excellent New York Times article about Dr. Gott's Copernican Principle at www.nytimes.com/2007/07/17/science/17tier.html. In our first long segment, Dr. Gott began our discussion by taking us through his new book which has many unique features in it. Its the universe in perspective as he has scaled it starting with lunar footprints. Not only did Dr. Gott take us through the book, the maps, the scaled photographs, the Sloan Great Wall of Galaxies, he talked about the visible universe and this took us into the Theory of Inflation and even a discussion on the possibility of extraterrestrial intelligent life. This then provided us with the introduction to the Copernican Principle and the theory that we on Earth are not special, therefore its likely that other possible intelligent life in the galaxy is not special. Most of the rest of our program was focused on the Copernican Principle, the urgency to commence space colonization on Mars, and the fact that our space program may end up being very short lived. Listeners called in and used email to ask Dr. Gott questions about being special or not and the Copernican Principle, to challenge, try to understand, and to disagree with Dr. Gott. At one point I told Dr. Gott that we have a hard time getting our arms around the possibility that we are not special and that perhaps other intelligent life in the galaxy is stuck on their planet as we seem to be stuck on ours. Several listeners joked about ET having a similar Congress to us, having funding cut, etc. but as you will hear, getting off our planet is hard to do, not just because of the technology, but because of the costs involved, the economics, and the political will which Dr. Gott said was the real barrier. At one point, I transported Dr. Gott to a congressional hearing and told him to state his case of urgency for Mars colonization now. Do you think he convinced Congress to fund our space program with a Mars colonization focus to it? Other topics came up during the first segment including inflation theory, relativity, interstellar travel, the age of our space program and its possible expected remaining life, and the survival of the species theory for space colonization and why humans need to be on two planets. In our second segment, Dr. Gott was challenged by Trent who brought up some of Dr. Gott's critics, including rebuttals by Carlton M. Caves. See what you think of this discussion. Dr. Gott responded to questions about SETI and explained why it was a low cost, worthwhile program with a big expected value potential payoff. In response to John's comment about the life expectancy of a ten year old, Dr. Gott showed us how the Copernican Principle predicted his life to be a minimum of a quarter of a year to a maximum of 390 years. He then applied the Principle to my age and if he is right, The Space Show has a chance of being around a long time. Toward the end of the discussion, Dr. Gott took us into the realm of time travel, both into the future and the past. You might be surprised by this discussion. Don't miss his closing comments and Pearls of Wisdom. For your questions and comments, post them on the blog URL above. You can also email them to Dr. Gott at jrg@astro.princeton.edu.