Saturns Mysterious Moons Cosmic Journeys - Saturns Mysterious Moons

Saturns Mysterious Moons Launched three years before the new century... a spacecraft wound its way through the empty reaches of the solar system. On Earth, its progress was little noted, as it swung twice by the planet Ven...

Saturns Mysterious Moons Launched three years before the new
century... a spacecraft wound its way through the empty reaches of
the solar system. On Earth, its progress was little noted, as it
swung twice by the planet Venus, then our moon. And Earth. The
asteroid belt. And Jupiter.Almost seven years later, on the first of
July 2004, the Cassini probe entered the orbit of Saturn. It then
began to compile what has become one of the greatest photographic
collections of all time, of a giant gas planet, surrounded by
colorful rings, guarded by a diverse collection of moons, and
millions of tiny moonlets. Within this record, is a trail of
clues... pointing to the energy sources and complex chemistry needed
to spawn life. What are these mysterious worlds telling us about the
universe, and Earth? In the outer reaches of the solar system, a
billion and a half kilometers from the Sun... there is a little
world known as Enceladus. Nearly all of the sunlight that strikes
its icy surface is reflected back into space, making it one of the
brightest objects in the solar system.At its equator, the average
temperature is minus 198 degrees Celsius. It can rise about 70
degrees higher in grooves that stretch across the south pole like
tiger stripes. Looming over it is the giant planet Saturn.In myth,
Saturn - the Roman name for the primal Greek God Chronos - was the
youngest son of Gaia, or Earth, and Uranus, sky. Wielding a scythe
provided by his mother, the story goes, Saturn confronted his
abusive father, castrating him. The blood of Uranus flowed into the
seas, fertilizing the Earth and giving rise to Enceladus and other
giant offspring. Saturns moon Enceladus has its own tangled story.
In 2005, the Cassini spacecraft spotted plumes of water vapor
shooting out into space from its south pole. More recent close
encounters have revealed jets of water, flavored by slightly salty
chemical compounds, spewing out from vents in the rough, cracked
polar terrain. That may mean that Enceladus harbors a remarkable
secret below its frigid surface A liquid ocean, and perhaps, a
chemical environment that could spawn simple life forms. Its not the
only promising stop in the realm of Saturn. The moon Titan is often
said to resemble Earth in its early days. It is lined with volcanoes
and a hazy atmosphere rich in organic compounds. While Enceladus is
the size of Great Britain, Titan is ten times larger, 50% larger
than our moon, and the second largest moon in our solar system.Weve
known about Titan since the astronomer Christian Huygens discovered
it in 1655, and Enceladus since William Herschel spotted it in
August 1789, just after the start of the French Revolution.
Scientists began to investigate these moons in earnest with the
launch of the two Voyager spacecraft in 1977. The lineup of outer
planets in the solar system allowed the spacecraft to fly past each
of them.They disclosed new details about their magnetic fields,
atmospheres, ring systems, and inner cores. But what really turned
heads were the varied shapes and surfaces of their moons. Theyve all
been pummeled over the millennia by wayward asteroids and comets. A
few appear to be sculpted by forces below their surfaces. Neptunes
largest moon Triton has few craters. Its marked with circular
depressions bounded by rugged ridges. There are also grooves and
folds that stretch for dozens of miles, a sign of fracturing and
deforming. Triton has geysers too, shooting some five miles above
the surface. But on this frigid moon -- so far from the Sun -- the
liquid that spouts is not water but nitrogen. Tiny Miranda, one of
27 known moons that orbit Uranus, wears a jumbled skin thats been
shaped and reshaped by forces within. Jupiters moon Io -- orbiting
perilously close to the giant planet is literally turning itself
inside out. Rivers of lava roll down from open craters that erupt
like fountains. Flying by Europa, Voyager documented a complex
network of criss-crossing grooves and ridges. In the 1990s, the
Galileo spacecraft went back to get a closer look. It found that
Europas surface is a crazy quilt of fractured plates, cliff faces
and gullies... amid long grooves like a network of superhighways.
How did it get like this? Then, heat rising up through a subsurface
ocean of liquid water cracks, and shifts, and spreads the icy
surface in a thousand different ways. Europas neighbors, Callisto
and Ganymede, show similar features, suggesting they too may have
liquid oceans below their surfaces. Crossing outward to Saturn,
Voyager found a similar surface on the moon Enceladus. So when the
Cassini spacecraft arrived in 2004, it came looking for answers to a
range of burning questions if this moon and others have subsurface
oceans? Do they also have the ability to cook up and support life?
And what could they tell us about the origin of life throughout the
galaxy?