Nearby Frontrunners for Life apart from Earth
(Top Posts - Science - 031107)

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Certainly, when looking for life apart from
Earth, the primary obstacles are distance,
and will. Do humans possess enough will
to spend the money required to enable
us to find Earthlike planets orbiting distant
stars, and closer to home, do humans have
the will required to visit -and- re-visit, with
manned craft -or- with unmanned probes,
the most likely locations for life in our own
solar system?

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http://images.stltoday.com/stltoday/multimedia/europa2.gif
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o Europa

Pros: Has a large salty ocean, could have
hot seafloor vents, icy crust could be thin,
tides may crack the ice allowing light and
oxygen to reach the ocean

Life on Europa? http://images.stltoday.com/stltoday/multimedia/europa.gif

Cons: Icy crust could be thick (making
detection of ocean life more difficult),
charged particles from Jupiter would
kill all surface life

o Mars

Pros: Has ice caps and may have deep
groundwater, meteorites from Earth
could have fertilized Mars with life, more
easily accessible from Earth

Cons: Ancient seas are now gone, life
is possible only underground

o Enceladus

Pros: A geyser of water was photographed
erupting into space, probes could sample
this water, could be like a mini-Europa

Cons: Geyser source may be only a small
puddle -- not an ocean, might lack an ocean
floor and be only a comet-like mixture of
rock -- ice -- water

o Titan

Pros: Has a thick atmospher of carbon-
based molecules, is a natural lab for con-
ditions before life began on Earth

Cons: An anti-greenhouse effect makes
the surface very cold, water is deep under-
ground and mixed with ammonia, has no
free oxygen

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