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Mars Phoenix Probe Successfully Launched
necro81 writes "The Mars Phoenix lander, built from the ashes of two earlier Mars missions, successfully launched atop a Delta II rocket from Canaveral this morning. The mission takes the 350-kg lander to northern latitudes (comparable to Greenland or Siberia) to investigate subsurface ice for the chemical precursors of life. The lander should arrive on Mars on May 25, 2008. 'NASA has never attempted to land a spacecraft on Mars at such a high northern latitude. A lander intended for the red planet's South Pole went silent immediately upon arrival in 1999. That failure, combined with the loss of the companion Mars orbiter, prompted NASA to cancel a 2001 lander mission. The parts from that scrapped mission were used for Phoenix, thus its name, which alludes to the mythological bird that rises from its own ashes.'"
The absence of a magnetic field on mars has some interesting consequences. Since Mars and Earth were formed from the same material, it is very surprising that Mars doesn't have oceans. One of the theories is that the solar wind of particles from the sun carried away the atmosphere, and so the oceans just evaporated away until it became so cold the remaining water froze into the polar ice caps. Recent estimates indicate that Mars loses some 100 tons of atmosphere every day. The Earth is protected from the solar wind by its magnetosphere, which results from the magnetic field. Mars's magnetic field, on the other hand, disappeared some 4 Billion years ago when the planet's core cooled off.