The Moon and the giant planet Jupiter dominate the sky this evening. Jupiter looks like a brilliant star to the left of the Moon as darkness falls.
Jupiter has lots of moons of its own -- more than 60, and still counting. A few of them are interesting worlds in their own right.
A prime example is Europa. It's about as big as our own moon, but its surface is coated with ice, which appears to float atop an ocean of liquid water.
The ocean is warmed by heat from Europa's interior. Water and energy are two key ingredients for life, so it's possible that living organisms could inhabit Europa.
When the Galileo spacecraft neared the end of its mission almost a decade ago, it was deliberately crashed into Jupiter instead of running the risk that it might someday hit Europa. And the same thing will happen to the next mission to Jupiter, called Juno, which is scheduled for launch later this year.
That's because, despite years of exposure to deadly radiation and the vacuum of space, there's always a remote chance that some Earthly "bug" might remain alive inside a visiting spacecraft. Transplanted microbes from Earth would make it harder to determine if any native microbes live on Europa. It's even possible that terrestrial microbes could flourish there, filling the seas of another world with alien life -- life transplanted from right here on Earth.
We'll have more about Jupiter and the Moon tomorrow.
Script by Damond Benningfield, Copyright 2010
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