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starship-design: Fermi's Paradox - Drake's Equation will have to be rewritten

This was published last week and presents an interesting solution to the
discussion we once had regarding drake's Equation....

Gamma-Ray Bursts May Explain SETI Silence
Published: 1999 January 21
11:31 pm ET (0431 UT)

Powerful blasts of radiation from an enigmatic astronomical phenomenon may
explain why we have not yet seen evidence of extraterrestrial intelligence,
one scientist has concluded.

In an article to be published in the January 23 issue of the magazine New
Scientist, Fermilab astrophysicist James Annis explains that gamma-ray
bursts (GRBs) may have inhibited the development of intelligent life in the
early universe.

"If one [GRB] went off in the Galactic center," Annis said, "we here
two-thirds of the way out on the Galactic disk would be exposed over a few
seconds to a wave of powerful gamma rays." Such radiation would be lethal to
life on land, he believes.

GRBs occur in galaxies only once every few hundred million years today, but
some theories suggest GRBs were more common in the early universe. Since a
single GRB is powerful enough to sterilize nearly an entire galaxy, it may
be only now that conditions have permitted the development of intelligent
life here and elsewhere in the universe.

"The GRB model essentially resets the available time for the rise of
intelligent life to zero each time a burst occurs," Annis said.

Such an explanation may be a solution to a half-century-old question on why
we have not seen evidence of extraterrestrial life. The problem, proposed by
Nobel laureate physicist Enrico Fermi and dubbed the "Fermi Paradox", notes
that a civilization traveling at only one-thousandth the speed of light
could traverse the galaxy in 100 million years, far less than the age of the
galaxy or the universe. "Where are they?" Fermi was said to have asked

GRBs, which may be caused by the collision of neutron stars or black holes,
can release as much energy in a few seconds as a supernova. That short
timescale could work against the theory, British physicist Paul Davies
points out. "If the drama is all over in a few seconds, you only zap half
the planet," he said. "The planet's mass shields the other side."

Secondary effects from the blast, such as the destruction of the ozone
layer, may be enough to wipe out life on the rest of the planet, Annis


Lee Parker