I don't see the contradiction between the view below, and the view that Earth
is
a life-experiment planet of inter-stellar society......Alfred
=====
Source: University of Washington
January 18, 2000
Vince Stricherz
206-543-2580
[EMAIL PROTECTED]
We Are Not Alone -- Or Are We?
The annals of science fiction are filled with advanced
extraterrestrial creatures like Klingons and Wookies, Vogons and
Romulans, all carrying on in a human sort of way. And while
screenwriters and novelists weave stories around these characters,
some people scour the heavens for signs that such highly evolved
beings really are out there.
But a new book by two University of Washington scientists contends
that, contrary to popular thought, we just might be alone and Earth
might be unique, if not in the universe at least in this celestial
neighborhood.
In "Rare Earth," published this month by Copernicus Books/Springer,
paleontologist Peter Ward and astronomer Donald Brownlee examine the
remarkable confluence of conditions and events that deposited
life-forming chemicals on Earth, allowed simple life to gain a
foothold and then protected the planet sufficiently and created just
the right environmental factors for advanced life to slowly evolve.
"It seems like something a lot of people don't want to hear, yet
nearly everyone who works in these areas has remarked at one time or
another how unusual the Earth is," said Brownlee, an expert on comets,
the space bodies that might have delivered the first organic chemicals
and life-sustaining water to Earth.
In fact, he and Ward, whose extensive research on the fossil record
has provided key insights into prehistoric mass extinctions,
frequently discuss the Earth's unusual character with students in
their astronomy and geological sciences classes.
The scientists don't argue that life is rare. In fact, recent evidence
showing simple microbial life can survive extreme conditions on Earth
is an indicator that such life also might be widespread in the galaxy
and the universe.
"But you need to have a vast amount of time to let evolution ramp up
to animals, and we think there are only a small number of planets
where that could happen," said Ward.
The key, he said, is having near equilibrium in such things as
temperature and water content over enormous time spans.
Microbes have shown they can live in some of the harshest Earth
environments imaginable, while advanced plant and animal life requires
a delicate balance of conditions.
"For 90 percent of the age of this planet, life was slime at the
bottom of the ocean," Brownlee said. But that life was given a
one-in-a-million opportunity to gradually evolve to the complexity it
enjoys today.
"The underlying theme of the book is that the Earth is a very charmed
planet," he said. "We know of no other body that is even remotely like
Earth."
Factors that made advanced life possible include the Earth's having:
* The proper distance from the sun to allow development of habitat for
complex life and ensure that water remains liquid, not vapor or ice.
* The proper mass to retain atmosphere and ocean.
* Plate tectonics, which act as a sort of atmospheric thermostat,
build land masses and enhance biotic diversity.
* A neighbor the size of Jupiter, not too close and not too far away,
that can use its gravity to protect the planet from too many
life-extinguishing collisions with comets and asteroids.
* A stable orbit unperturbed by giant planets.
* A large moon at the right distance to stabilize tilt, thus ensuring
seasonal climate fluctuations that are not too severe.
* Enough carbon to support development of life but not so much to
allow for runaway greenhouse conditions.
In addition, Brownlee and Ward contend, the solar system's position in
the Milky Way galaxy also is key to life development on Earth. At the
edge of the galaxy, many stars are too metal-poor for planet
formation, while the center of the galaxy has extreme energy processes
that would hinder complex life.
The "charmed" conditions on Earth won't always be present. Someday,
some way, evolution on Earth will end. That could be when the sun gets
so hot that life can no longer survive, when ultimately the ocean
boils and surface rocks melt.
"There will be a time when there will be no record of life ever having
existed on Earth," Brownlee said.
He and Ward acknowledge that their assumptions about how uncommon
advanced life might be in the universe are based on observed
conditions that allowed evolution on Earth. But this is the only place
in which advanced life is known to have occurred, and it is one of
only a handful of places in the solar system where even microbial life
is suspected, making this planet the ultimate laboratory on advanced
life.
A key condition for life on Earth is the presence of carbon, because
of its unique properties.
"Probably all life is based on carbon," Brownlee said. While he
concedes the possibility that life has evolved elsewhere based on an
element such as silicon, he remains skeptical of that theory.
"Many things are possible. You can never imagine everything the
universe can do. But we know it didn't happen here," Brownlee said.
"If things have to obey physical and chemical laws, then there really
aren't a lot of options in nature."
For more information, contact:
Ward at (206) 543-2962
[EMAIL PROTECTED]
Brownlee at (206) 543-8575
[EMAIL PROTECTED]
Note: Don Brownlee is the Principal Investigator of the STARDUST
mission.
Mark
Alien Astronomer - "Exploring Our Universe"
http://www.geocities.com/Area51/Shadowlands/6583
Astronomy - Hi-Tech/Secret Projects - Secret Societies - Ufology
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
=====
UFOTruth - http://UFOTruth.listbot.com
Source: University of Washington
January 18, 2000
Vince Stricherz
206-543-2580
[EMAIL PROTECTED]
We Are Not Alone -- Or Are We?
The annals of science fiction are filled with advanced
extraterrestrial creatures like Klingons and Wookies, Vogons and
Romulans, all carrying on in a human sort of way. And while
screenwriters and novelists weave stories around these characters,
some people scour the heavens for signs that such highly evolved
beings really are out there.
But a new book by two University of Washington scientists contends
that, contrary to popular thought, we just might be alone and Earth
might be unique, if not in the universe at least in this celestial
neighborhood.
In "Rare Earth," published this month by Copernicus Books/Springer,
paleontologist Peter Ward and astronomer Donald Brownlee examine the
remarkable confluence of conditions and events that deposited
life-forming chemicals on Earth, allowed simple life to gain a
foothold and then protected the planet sufficiently and created just
the right environmental factors for advanced life to slowly evolve.
"It seems like something a lot of people don't want to hear, yet
nearly everyone who works in these areas has remarked at one time or
another how unusual the Earth is," said Brownlee, an expert on comets,
the space bodies that might have delivered the first organic chemicals
and life-sustaining water to Earth.
In fact, he and Ward, whose extensive research on the fossil record
has provided key insights into prehistoric mass extinctions,
frequently discuss the Earth's unusual character with students in
their astronomy and geological sciences classes.
The scientists don't argue that life is rare. In fact, recent evidence
showing simple microbial life can survive extreme conditions on Earth
is an indicator that such life also might be widespread in the galaxy
and the universe.
"But you need to have a vast amount of time to let evolution ramp up
to animals, and we think there are only a small number of planets
where that could happen," said Ward.
The key, he said, is having near equilibrium in such things as
temperature and water content over enormous time spans.
Microbes have shown they can live in some of the harshest Earth
environments imaginable, while advanced plant and animal life requires
a delicate balance of conditions.
"For 90 percent of the age of this planet, life was slime at the
bottom of the ocean," Brownlee said. But that life was given a
one-in-a-million opportunity to gradually evolve to the complexity it
enjoys today.
"The underlying theme of the book is that the Earth is a very charmed
planet," he said. "We know of no other body that is even remotely like
Earth."
Factors that made advanced life possible include the Earth's having:
* The proper distance from the sun to allow development of habitat for
complex life and ensure that water remains liquid, not vapor or ice.
* The proper mass to retain atmosphere and ocean.
* Plate tectonics, which act as a sort of atmospheric thermostat,
build land masses and enhance biotic diversity.
* A neighbor the size of Jupiter, not too close and not too far away,
that can use its gravity to protect the planet from too many
life-extinguishing collisions with comets and asteroids.
* A stable orbit unperturbed by giant planets.
* A large moon at the right distance to stabilize tilt, thus ensuring
seasonal climate fluctuations that are not too severe.
* Enough carbon to support development of life but not so much to
allow for runaway greenhouse conditions.
In addition, Brownlee and Ward contend, the solar system's position in
the Milky Way galaxy also is key to life development on Earth. At the
edge of the galaxy, many stars are too metal-poor for planet
formation, while the center of the galaxy has extreme energy processes
that would hinder complex life.
The "charmed" conditions on Earth won't always be present. Someday,
some way, evolution on Earth will end. That could be when the sun gets
so hot that life can no longer survive, when ultimately the ocean
boils and surface rocks melt.
"There will be a time when there will be no record of life ever having
existed on Earth," Brownlee said.
He and Ward acknowledge that their assumptions about how uncommon
advanced life might be in the universe are based on observed
conditions that allowed evolution on Earth. But this is the only place
in which advanced life is known to have occurred, and it is one of
only a handful of places in the solar system where even microbial life
is suspected, making this planet the ultimate laboratory on advanced
life.
A key condition for life on Earth is the presence of carbon, because
of its unique properties.
"Probably all life is based on carbon," Brownlee said. While he
concedes the possibility that life has evolved elsewhere based on an
element such as silicon, he remains skeptical of that theory.
"Many things are possible. You can never imagine everything the
universe can do. But we know it didn't happen here," Brownlee said.
"If things have to obey physical and chemical laws, then there really
aren't a lot of options in nature."
For more information, contact:
Ward at (206) 543-2962
[EMAIL PROTECTED]
Brownlee at (206) 543-8575
[EMAIL PROTECTED]
Note: Don Brownlee is the Principal Investigator of the STARDUST
mission.
Mark
Alien Astronomer - "Exploring Our Universe"
http://www.geocities.com/Area51/Shadowlands/6583
Astronomy - Hi-Tech/Secret Projects - Secret Societies - Ufology
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
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