Looking for Earths
By Alan Boss
John Wiley, £20.50 and £12.50
Although a little out of date already, this book describes the discovery of planets around other stars, one of the most significant achievements of the 1990s. For the first time, we have evidence that there are numerous solar systems strewn across the universe, so the chances of extraterrestrial life move from the possible to the probable. Alan Boss calls this "as significant as Neil Armstrong's first step onto the Moon".
Looking for Earths is an excellent primer for the discoveries that are sure to come over the next decade. Virtually every major project, including the Very Large Telescope, has planetary searches as part of its mission.
So far, the detection of planets has been largely indirect, because the brightness of the star tends to swamp any light reflected off the planet. An example of indirect observation is searching for a star that wobbles, presumably due to the gravitational pull of an orbiting planet. However, the ambition is to make a direct observation, which might be possible by searching beyond the visible wavelengths. In the visible region, a star is typically a million times brighter than any orbiting planet, whereas it is only a thousand times brighter in terms of infrared.
Hubble Space Telescope - New Views of the Universe
By Mark Voit
Abrams, £12.95
The latest book of glossy Hubble Space Telescope images, 110 in total, each with an explanation. The book accompanies an exhibition of the images, organised by the Smithsonian Institution and the Space Telescope Science Institute.
It includes the classics, such as a psychedelic Saturn viewed at infrared wavelengths, the comet Shoemaker-Levy 9 and its crash with Jupiter, colliding galaxies and black hole candidates. One way to increase political support for astronomy might be to send this book to every MP.