Viking 2
Mars and the Asteroid Belt
Mars
Mars is the forth closest planet to the Sun and takes almost seven hundred Earth days to orbit. A day on Mars is less than an hour longer than a day on Earth. Mars is the next brightest object in the sky after Venus. Like Mercury and Venus, Mars is named after a Roman God, the god of war.
The Star Garden
HTML Comment Box is loading comments...
Mercury Venus Earth Mars (to scale)
Mars is red for the same reason that rust is, because the iron on its surface is oxidised. Mars has a thin atmosphere mostly composed of carbon dioxide and its surface is covered in craters, inactive volcanoes, valleys, deserts and ice caps. Mars hosts the largest known mountain in the Solar System, Mount Olympus, and the largest canyon, Valles Marineris.
Viking 1 Launch
In 1971, NASA's Mariner 9 probe found water on Mars and showed that it had once contained rivers which had led to the formation of large and complex canyons. It must also have contained a weather system as there is evidence of rain or snow. In 1976, NASA's Viking 1 and 2 spacecrafts reached Mars, confirming that it had once contained both rain and oceans. In 2008, NASA's Phoenix Mars Lander directly sampled frozen water found in shallow Martian soil.
Mars has two moons, Phobos and Deimos, which were discovered in 1877, these are thought to be asteroids that were captured by Mars' gravitational pull.
Phobos Deimos
The Asteroid Belt
The asteroid belt is composed of boulders made of carbon, silicon, iron and semi-precious stones, which orbit in the space between Mars and Jupiter. Asteroids are not massive enough to become spherical and are prevented from becoming gravitationally bound, and forming a planet, because of the strong gravitational pull of Jupiter.
Over half of the mass of the asteroid belt is contained within four objects known as, Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. These are all over four hundred kilometres in diameter. The largest asteroid, Ceres, was discovered by Italian astronomer Giuseppe Piazzi in 1801. It is almost a thousand kilometres in diameter and was accepted as a planet for almost fifty years. NASA's Pioneer 10 probe was the first spacecraft to travel through the asteroid belt in 1972.