EXTRHTERHESTRIRLS HUD UFOS
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Another obvious defect might be SETI researchers' reliance on
certain radio frequency bands. If there is alien life, it may use compression techniques or might disperse messages via smaller packages,
strategies that are used on the modern Internet today. Listening in on
compressed messages that have been spread over many frequencies,
we might hear only random noise.
But given all the formidable problems facing SETI, it is reasonable
to assume that sometime in this century we should be able to detect
some signal from an extraterrestrial civilization, assuming that such
civilizations exist. And should that happen, it would represent a milestone in the history of the human race.
WHERE ARE THEY?
The fact that the SETI project so far has found no indication of signals
from intelligent life in the universe has forced scientists to take a cold,
hard look at the assumptions behind Frank Drake's equations for intelligent life on other planets. Recently astronomical discoveries have led
us to believe that the chance of finding intelligent life are much different than originally computed by Drake in the 1960s. The chance that
intelligent life exists in the universe is both more optimistic and more
pessimistic than originally believed.
First, new discoveries have led us to believe that life can flourish in
ways not considered by Drake's equations. Before, scientists believed
that liquid water can exist only in the "Goldilocks zone" surrounding
the sun. (The distance from Earth to the sun is "just right." Not too close
to the sun, because the oceans would boil, and not too far away, because the oceans would freeze, but "just right" to make life possible.)
So it came as a shock when astronomers found evidence that liquid water may exist beneath the ice cover on Europa, a frozen moon of
Jupiter. Europa is well outside the Goldilocks zone, so it would appear
not to fit the conditions of Drake's equation. Yet tidal forces might be
sufficient to melt the ice cover of Europa and produce a permanent liquid ocean. As Europa spins around Jupiter, the planet's huge gravita-
m
Another obvious defect might be SETI researchers' reliance on
certain radio frequency bands. If there is alien life, it may use compression techniques or might disperse messages via smaller packages,
strategies that are used on the modern Internet today. Listening in on
compressed messages that have been spread over many frequencies,
we might hear only random noise.
But given all the formidable problems facing SETI, it is reasonable
to assume that sometime in this century we should be able to detect
some signal from an extraterrestrial civilization, assuming that such
civilizations exist. And should that happen, it would represent a milestone in the history of the human race.
WHERE ARE THEY?
The fact that the SETI project so far has found no indication of signals
from intelligent life in the universe has forced scientists to take a cold,
hard look at the assumptions behind Frank Drake's equations for intelligent life on other planets. Recently astronomical discoveries have led
us to believe that the chance of finding intelligent life are much different than originally computed by Drake in the 1960s. The chance that
intelligent life exists in the universe is both more optimistic and more
pessimistic than originally believed.
First, new discoveries have led us to believe that life can flourish in
ways not considered by Drake's equations. Before, scientists believed
that liquid water can exist only in the "Goldilocks zone" surrounding
the sun. (The distance from Earth to the sun is "just right." Not too close
to the sun, because the oceans would boil, and not too far away, because the oceans would freeze, but "just right" to make life possible.)
So it came as a shock when astronomers found evidence that liquid water may exist beneath the ice cover on Europa, a frozen moon of
Jupiter. Europa is well outside the Goldilocks zone, so it would appear
not to fit the conditions of Drake's equation. Yet tidal forces might be
sufficient to melt the ice cover of Europa and produce a permanent liquid ocean. As Europa spins around Jupiter, the planet's huge gravita-