Cosmic microwave background
Cosmic microwave background. Spherical projection of the cosmic microwave background, using all-sky data from the WMAP (Wilkinson Microwave Anisotropy Probe). Since it is a spherical projection, it only shows half the sky. The microwave background is radiation from the beginning of the universe (actually 380, 000 years after its creation) that has been stretched (cooled to around 3 Kelvin) by the expansion of the universe. The colours show the variation in the temperature (then equivalent to density) of the early universe. Denser regions (red, yellow) formed the seeds of galaxies and other structures. Data obtained in 2003.
© NASA/WMAP SCIENCE TEAM/SCIENCE PHOTO LIBRARY
Green and red seeds of nutmeg and mace, Myristica
Green and red seeds of nutmeg and mace, Myristica fragrans Houtt. . Color-printed woodblock engraving by Kan'en Iwasaki from Honzo Zufu, an Illustrated Guide to Medicinal Plants, 1884. Iwasaki (1786-1842) was a Japanese botanist, entomologist and zoologist. He was one of the first Japanese botanists to incorporate western knowledge into his studies.
© Florilegius / Mary Evans
Panspermia theory of life
Panspermia, conceptual image. Panspermia is the theory that the seeds of life on Earth, such as water and organic matter, arrived from outer space. Here, eggs impact water and crack open, releasing seeds into the water. In the theory of panspermia, impacts from comets and other bodies would do the same, kickstarting the evolution of life on Earth. Recent research, from probes such as Deep Impact in July 2005, have revealed that comets do contain water and organic materials, which lends weight to the theory. Panspermia is an ancient notion, but its leading modern proponent was the cosmologist Sir Fred Hoyle (1915-2001).
© DR.JOHN BRACKENBURY/SCIENCE PHOTO LIBRARY