Images Dated 25th January 2005

Light micrograph of a rat testis

Light micrograph of a transverse section through a mammalian testis showing the seminiferous tubules, highly convoluted tubes lined with a stratified epithelium. The production of male gametes (spermatogenesis) and the subsequent development of these gametes into motile spermatozoa (spermiogenesis) both take place within this epithelium. Sertoli cells, which provide support and nourishment for the developing spermatozoa, are also found within the epithelium. Leydig cells, which have an endocrine function, are found either singly or in clumps in the interstitial spaces between the tubules. Magnification: x200 at 35mm size. RAT TESTIS

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Moon base

Moon base. Computer artwork of an astronaut at a base on the Moon. Humans will require protective suits and sealed buildings when on the Moon. This is because the Moon has no atmosphere and a wide range of surface temperatures from -170 (night) to 127 (day) degrees Celsius. The lunar day-and-night cycle is nearly 30 Earth-days long. The Moon has a gravity that is about a sixth of that of the Earth. Storage tanks (upper left) will include the water, oxygen and fuel needed by the astronauts. A wheel of a moon rover is seen at right. On the ground are solar panels to provide energy. The Moon is about 384, 000 kilometres from the Earth (seen in background)

© CHRISTIAN DARKIN/SCIENCE PHOTO LIBRARY

Mars colony

Mars colony, computer artwork. The first bases on Mars are likely to resemble chemical plants. They will have sealed buildings to protect colonists from the thin atmosphere that is nearly all carbon dioxide, and the freezing surface temperature that ranges from -89 to -31 degrees Celsius. Inside the large domes, there are plants that will help recycle the carbon dioxide into oxygen, and also provide food. The tanks around the base will store oxygen, water, fuel and other chemicals. These may be manufactured from raw materials on Mars. Mars is a rocky, desert world, and has a gravity around a third of that of Earth

© CHRISTIAN DARKIN/SCIENCE PHOTO LIBRARY