Saturn Gallery

James Clerk Maxwell, caricature

James Clerk Maxwell (1831-1879). Caricature of the Scottish physicist James Clerk Maxwell. Maxwell's works cover a wide area of science, and he is regarded as one of the finest minds of the 19th century. His major work was on light and electromagnetic waves. He showed that oscillating charges produced waves in an electromagnetic field, and that these waves had the same velocity as light. This led him to predict other forms of electromagnetic radiation, such as radio waves. His equations introduced the value c for the speed of light. He also worked on the motions of molecules in a gas, and showed that Saturn's rings must be composed of numerous particles

© GARY BROWN/SCIENCE PHOTO LIBRARY

Quantised orbits of the planets

Quantum orbits of the planets. Conceptual computer artwork showing the planets of the solar system on a model of atomic orbitals. This represents the theory that the orbits of the planets were determined by similar physical principles to those governing the orbits of electrons. Electrons can only occupy distinct energy levels around an atom, rather than having the capability to be anywhere. These quantum levels are determined by the electron's energy. The theory that similar effects occur at the solar system scale is controversial and not widely accepted, as the orbits can be explained by well-understood gravitational theory

© MEHAU KULYK/SCIENCE PHOTO LIBRARY

Planets internal structures

Planets internal structures, and Pluto, computer artwork. Mercury, Mars and Venus consist of a large iron core (spherical), surrounded by a thick silicate mantle (yellow) covered in a surface crust. Earth consists of an inner core of solid iron and nickel (yellow) and a molten outer core (orange), surrounded by a mantle of highly viscous liquid (brown) covered by a surface crust. Jupiter and Saturn consist of a core of rock (spherical) surrounded by ice (mat grey). This is surrounded by a layer of liquid metallic hydrogen (grey) and liquid normal hydrogen (blue). Uranus and Neptune have a core of rock (spherical) surrounded by ice and liquid hydrogen (blue). Pluto has a dense rocky core (grey) surrounded by ice (black)

© CHRISTIAN DARKIN/SCIENCE PHOTO LIBRARY