Credit: NASA
(1) Giant asteroids may have wiped out Mars's magnetic field. The energy released by
massive collisions upset the heat flow in the planet's iron core that produced the
magnetism.
一次超級隕擊所產生的巨大能量可能導致火星的磁場瞬間消失． http://sciencenow.sciencemag.org/cgi/content/full/2009/430/2
Credit: NASA/JPL
(2) 2009 HC82 is of a 2- to 3-kilometre-wide asteroid in an orbit that goes backwards. It
comes closer to Earth than any other object in a 'retrograde' orbit.
天文學家發現一顆逆行的近地小行星，這顆小行星會在地球1千5百萬公里之上空掠過． http://www.newscientist.com/arti ... o-liquid-ocean.html
發表於 2009-5-9 11:30:02