136
PHYSICS OF THE IMPOSSIBLE
other side would be freezing cold for long periods of time; if the
Earth rotated too quickly, there would be extremely violent weather
conditions, such as monster winds and storms.
• A location that is the right distance from the center of the galaxy. If
the Earth were too close to the center of the Milky Way galaxy, it
would be hit with dangerous radiation; if it were too far from the
center, our planet would not have enough higher elements to create
DNA molecules and proteins.
For all these reasons astronomers now believe that life might exist
outside the Goldilocks zone on moons or wandering planets, but that
the chances of the existence of a planet like Earth capable of supporting life within the Goldilocks zone are much lower than previously believed. Overall most estimates of Drake's equations show that the
chances of finding civilization in the galaxy are probably smaller than
he originally estimated.
As Professors Peter Ward and Donald Brownlee have written, "We
believe that life in the form of microbes and their equivalents is very
common in the universe, perhaps more common than even Drake and
[Carl] Sagan envisioned. However, complex life-animals and higher
plants-is likely to be far more rare than is commonly assumed." In
fact, Ward and Brownlee leave open the possibility that the Earth may
be unique in the galaxy for harboring animal life. (Although this theory may dampen the search for intelligent life in our galaxy, it still
leaves open the possibility of life existing in other distant galaxies.)
THE SEARCH FOR EARTH-LIKE
PLANETS
Drake's equation, of course, is purely hypothetical. That is why the
search for life in outer space has gotten a boost from the discovery of
extrasolar planets. What has hindered research into extrasolar planets
is that they are invisible to any telescope since they give off no light of
their own. They are in general a million to a billion times dimmer than
the mother star.
PHYSICS OF THE IMPOSSIBLE
other side would be freezing cold for long periods of time; if the
Earth rotated too quickly, there would be extremely violent weather
conditions, such as monster winds and storms.
• A location that is the right distance from the center of the galaxy. If
the Earth were too close to the center of the Milky Way galaxy, it
would be hit with dangerous radiation; if it were too far from the
center, our planet would not have enough higher elements to create
DNA molecules and proteins.
For all these reasons astronomers now believe that life might exist
outside the Goldilocks zone on moons or wandering planets, but that
the chances of the existence of a planet like Earth capable of supporting life within the Goldilocks zone are much lower than previously believed. Overall most estimates of Drake's equations show that the
chances of finding civilization in the galaxy are probably smaller than
he originally estimated.
As Professors Peter Ward and Donald Brownlee have written, "We
believe that life in the form of microbes and their equivalents is very
common in the universe, perhaps more common than even Drake and
[Carl] Sagan envisioned. However, complex life-animals and higher
plants-is likely to be far more rare than is commonly assumed." In
fact, Ward and Brownlee leave open the possibility that the Earth may
be unique in the galaxy for harboring animal life. (Although this theory may dampen the search for intelligent life in our galaxy, it still
leaves open the possibility of life existing in other distant galaxies.)
THE SEARCH FOR EARTH-LIKE
PLANETS
Drake's equation, of course, is purely hypothetical. That is why the
search for life in outer space has gotten a boost from the discovery of
extrasolar planets. What has hindered research into extrasolar planets
is that they are invisible to any telescope since they give off no light of
their own. They are in general a million to a billion times dimmer than
the mother star.