Tuesday, September 30, 2003
Farewell, Galileo
Since I touched upon Galileo briefly in my previous post, I might as well make a post on his namesake -- the satellite -- which crashed into Jupiter last week. Having watched a lot of Galileo images and news over the past 10 years, including the collision of Shoemaker-Levy into Jupiter, I thought Galileo was at least as successful at unlocking space-secrets as the Hubble telescope. Among the spacecraft's observations, the key ones were its findings about the Galilean satellites, especially Europa and Callisto.
Researchers had long suspected that Europa might have an ocean. Galileo confirmed that it does, though the liquid water is located beneath an icy crust. Indeed, Europa's ocean could be as much as 100km deep, which would mean that Europa has more water on it than Earth. Callisto, too, may have an ocean beneath its icy surface, though this is less certain. The ocean on Earth is thought to have been where life started, so these discoveries have led optimists to wonder whether the moons of Jupiter, rather than the deserts of Mars, may yield the first signs of extraterrestrial life.
Interestingly, it was the discovery of Europa's oceans that prompted scientists to crash Galileo into Jupiter, to avoid an accidental collision with Europa. There is a minor possibility that Galileo might have carried a microbe from Earth into orbit and if so, a collision with Europa would contaminate the satellite. It would be truly unfortunate if someday we do manage to launch a probe to study Europa's oceans for life and found instead a microbe from earth. Arthur C. Clarke wrote in 2010, "All these worlds are yours, except Europa. Attempt no landings there." Make that "no crash landings"!
Researchers had long suspected that Europa might have an ocean. Galileo confirmed that it does, though the liquid water is located beneath an icy crust. Indeed, Europa's ocean could be as much as 100km deep, which would mean that Europa has more water on it than Earth. Callisto, too, may have an ocean beneath its icy surface, though this is less certain. The ocean on Earth is thought to have been where life started, so these discoveries have led optimists to wonder whether the moons of Jupiter, rather than the deserts of Mars, may yield the first signs of extraterrestrial life.
Interestingly, it was the discovery of Europa's oceans that prompted scientists to crash Galileo into Jupiter, to avoid an accidental collision with Europa. There is a minor possibility that Galileo might have carried a microbe from Earth into orbit and if so, a collision with Europa would contaminate the satellite. It would be truly unfortunate if someday we do manage to launch a probe to study Europa's oceans for life and found instead a microbe from earth. Arthur C. Clarke wrote in 2010, "All these worlds are yours, except Europa. Attempt no landings there." Make that "no crash landings"!
