"The universe is simmering down, like a giant stew left to cook for four billion years. Sooner or later we won't be able to tell the carrots from the onions." -- Arthur Bloch
History: The possibility of ET's has been discussed for a long time. The physicist Frank Tipler published a "A Brief History of the Extraterrestrial Intelligence Concept" as an appendix to the Dover republication (1985) of his "Extraterrestrial Intelligent Beings Do Not Exist" (Tony Rothman et. al., Frontiers of Modern Physics). Tipler cites ancient and medieval speculation on the subject, but says that scientific discussion began in the mid to late 19th century. Tipler's paper originally appeared in the Quarterly Journal of the Royal Astronomical Society. A summary of his argument is on this site.
Observational evidence seems to indicate that the universe will expand forever. See
Astronomers have been looking for the "missing mass" of the universe, and have found a lot. However, the recent observations imply that there simply is not enough of it to stop the Hubble expansion. I expect there will be a lot of work soon on attempts to confirm or refute this conclusion, so the search for missing mass is not over.
Consistent with this, and reinforcing the conclusion, are observations indicating that Einstein's Cosmological Constant is positive. See The Case for a Positive Cosmological Lambda-term. Until very recently it was believed to be close to or equal to zero.
These discoveries have implications for some recent speculation about the place of intelligent life in the far future of the universe.
Quasars: Quasars are much smaller than galaxies, on the order of light-days. Some quasars have been observed to fluctuate in brightness, with a period of days. In order to preserve some causal connection the diameter therefore cannot be more than a few light-days. Hence they must have an incredibly powerful energy source in that small space, and the only possibility known to current physics is a black hole.
The universe is not a black hole.
The book is based on a course at the US Air Force Academy, so it does seem sort of appropriate for science fiction fans, particularly those who enjoyed Robert Heinlein's Space Cadet (One of my favorites).
Also, it is a Dover paperback, which means, that as technical books go, it is cheap!
Planet X: Is there an undiscovered planet in
our solar system?
It would have to be in quite a distant orbit--well beyond Neptune and
Pluto. Otherwise it would make itself noticed by perturbing the orbits
of the known planets, and of the Pioneer and Voyager spacecraft. It
would also have had to avoid detection in the various sky surveys that
have been conducted since the discovery of Pluto.
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©1996, 2002 by Glenn T. McDavid
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