Space Physics

"We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special."
- Stephen Hawking

Space Physics

Space physics is the study of the space environment and its interaction with the Earth. The gases that we know in our everyday lives consist of neutral atoms. The gases in space exist in a hot, fully ionised state called plasma in which the constituent particles are charged electrons and ions. Because of this, plasma interacts with electric and magnetic fields very differently than gas made of neutral atoms or molecules. Plasma physics has long been studied in laboratories. However, space provides a natural and large scale laboratory for the study of plasma processes. Space physicists seek to understand the complex plasma environment of the Earth, shaped by the interaction of the solar wind with the atmosphere and magnetic field of the Earth. They do this by studying aurorae, geomagnetic storms, cosmic ray acceleration and propagation, solar flares, etc. These phenomena are studied through in situ measurements by satellites, rockets and measurements done from the ground using radars and photometers. South African space scientists work at the Hermanus Magnetic Observatory, the South African base in Antarctica and at various universities.

"Space weather" is the term applied when the phenomena of space physics assume practical or economic significance. From a space physics perspective it could be said that the Earth is inside the extended atmosphere of the Sun. Therefore, the effects of storms on the sun are felt on the Earth. Particularly severe storms interfere with the operation of, or cause serious damage to, spacecraft systems, radio signals, aircraft navigation, oil pipelines, etc. The same satellites that observe the sun and study space physics can be used to provide early warning of the onset of severe space weather events, allowing operators of sensitive systems to take evasive action.