Phaeton (hypothetical planet) Only in 1949 did the well-known Soviet astronomer Sergej Vladirimovich Orlov give it the name Phaeton... This name has become established." Theories regarding the formation of the asteroid belt from the destruction of a hypothetical fifth planet are today collectively referred to as the "disruption theory". This theory states that there was once a major planetary member of our solar system circulating in the present gap between Mars and Jupiter, which was variously destroyed when: Today, the Phaeton hypothesis has been superseded by the accretion model. Most astronomers today believe that the asteroids in the main belt are remnants of
Mars Radiation Environment Experiment be experienced by future astronauts and it helped determine possible effects of Martian radiation on human beings. Space radiation comes from cosmic rays emitted by our local star, the Sun, and from stars beyond the Solar System as well. Space radiation can trigger cancer and cause damage to the central nervous system. Similar instruments are flown on the Space Shuttles and on the International Space Station (ISS), but none have ever flown outside Earth's protective magnetosphere, which blocks much of this radiation from reaching the surface of our planet. In the autumn of 2003 after a series of particularly strong