Mars is the fourth planet out from the Sun, orbiting at a mean distance of 228 million km (about 1.5 times that of the Earth). Mars shows some amazing similarities with the Earth: its day is 24 hours and 37 minutes long, a diurnal cycle that inhabitants from Earth could easily get used to, and the inclination of its axis is 24º, which means it has seasons. However, Mars is smaller than Earth (about one tenth of the mass), it has a lower surface gravity, and has a typical surface temperature of -20 to -120ºC. The similarities and differences make Mars a fascinating natural laboratory; its study will ultimately enable us to understand the origin and evolution of the Earth more completely.
Mars is interesting for many reasons: it has an atmosphere with weather systems, the surface is dynamic comprising in part dune fields and polar ice caps, and it clearly had water on its surface at some point in the past. Most recently it has been discovered that liquid water was probably present on Mars within the last million years. In other words, the episodic release of water could have taken place for the entire history of the planet. This opens up the possibility that life could have evolved billions of years ago and still be present today.
PSSRI has been at the forefront of the scientific investigation of Mars for many years through detailed studies of martian meteorites, spaceflight experiments such as Beagle2 and ExoMars and laboratory simulations of martian environments and processes.
Image courtesy of NASA