Of course Galileo made great use of the telescope, and his discoveries--that Jupiter has its own moons, that the Milky Way is made of stars, that Venus has phases just like the moon--were turning points.

FORBES: The Universe and Mrs. Ferguson

But the best reason that we have to believe in the moons of Jupiter is that no one has to be prepared to die for them in order for them to be real.

NEWYORKER: Moon Man

Galileo, which has spent the past two years studying Jupiter and its four largest moons, will now concentrate on Europa's icy crust.

CNN: Galileo moves on to Europa

It is running out of fuel for its thrusters, and once that has gone its path will be at the whim of the gravitational fields of Jupiter and its moons.

ECONOMIST: Galileo and Jupiter