LanceGary
09-12-2010, 13:43
Evidence for ET is mounting daily, but not proven
December 8th, 2010 in Space & Earth / Space Exploration
(AP) -- Lately, a handful of new discoveries make it seem more likely
that we are not alone - that there is life somewhere else in the
universe.
In the past several days, scientists have reported there are three
times as many stars as they previously thought. Another group of
researchers discovered a microbe can live on arsenic, expanding our
understanding of how life can thrive under the harshest environments.
And earlier this year, astronomers for the first time said they'd
found a potentially habitable planet.
"The evidence is just getting stronger and stronger," said Carl
Pilcher, director of NASA's Astrobiology Institute, which studies the
origins, evolution and possibilities of life in the universe. "I think
anybody looking at this evidence is going to say, 'There's got to be
life out there.'"
A caveat: Since much of this research is new, scientists are still
debating how solid the conclusions are. Some scientists this week have
publicly criticized how NASA's arsenic-using microbe study was
conducted, questioning its validity.
Another reason not to get too excited is that the search for life
starts small - microscopically small - and then looks to evolution for
more. The first signs of life elsewhere are more likely to be closer
to slime mold than to ET. It can evolve from there.
Scientists have an equation that calculates the odds of civilized life
on another planet. But much of it includes factors that are pure
guesswork on less-than-astronomical factors, such as the likelihood of
the evolution of intelligence and how long civilizations last.
Stripped to its simplistic core - with the requirement for
intelligence and civilization removed - the calculations hinge on two
basic factors: How many places out there can support life? And how
hard is it for life to take root?
What last week's findings did was both increase the number of
potential homes for life and broaden the definition of what life is.
That means the probability for alien life is higher than ever before,
agree 10 scientists interviewed by The Associated Press.
Seth Shostak, senior astronomer at the SETI Institute in California,
ticks off the astronomical findings about planet abundance and
Earthbound discoveries about life's hardiness. "All of these have gone
in the direction of encouraging life out there and they didn't have
to."
Two new studies published online Wednesday in the journal Nature add
to the interest in weird planets outside our solar system, though they
don't exactly make a stronger case for life. One study found a super-
hot planet much bigger than Jupiter that seems to be full of carbon in
its atmosphere. In the other study, astronomers found a star with at
least four large young planets, challenging past assumptions that
there's a limit to how many huge planets a star system could have.
Scientists who looked for life were once dismissed as working on the
fringes of science. Now, Shostak said, it's the other way around. He
said that given the mounting evidence, to believe now that Earth is
the only place harboring life is essentially like believing in
miracles. "And astronomers tend not to believe in miracles."
Astronomers, however, do believe in proof. They don't have proof of
life yet. There's no green alien or even a bacterium that scientists
can point to and say it's alive and alien. Even that arsenic-munching
microbe discovered in Mono Lake in California isn't truly alien. It
was manipulated in the lab.
But, says NASA astrobiologist Chris McKay, who has worked on searches
for life on Mars and extreme places on Earth, "There are real things
we can point to and show that being optimistic about life elsewhere is
not silly."
First, there's the basic question of where such life might exist.
Until a few years ago, astronomers thought life was only likely to be
found on or around planets circling stars like our sun. So that's
where the search of life focused - on stars like ours.
That left out the universe's most common stars: red dwarfs, which are
smaller than our sun and dimmer. Up to 90 percent of the stars in the
universe are red dwarf stars. And astronomers assumed planets circling
them would be devoid of life.
But three years ago, NASA got the top experts in the field together.
They crunched numbers and realized that life could exist on planets
orbiting red dwarfs. The planets would have to be closer to their star
and wouldn't rotate as quickly as Earth. The scientists considered
habitability and found conditions near these small stars wouldn't be
similar to Earth but would still be acceptable for life.
That didn't just open up billions of new worlds, but many, many times
that.
Last week, a Yale University astronomer said he estimates there are
300 sextillion stars - triple the previous number. Lisa Kaltenegger of
Harvard University says scientists now believe that as many as half
the stars in our galaxy have planets that are two to 10 times the size
of Earth - "super Earths" which might sustain life.
Then the question is how many of those are in the so-called Goldilocks
zone - not too hot, not too cold. The discovery of such a planet was
announced in April, although some scientists are challenging that.
The other half of the equation is: How likely is life? Over the past
decade and a half, scientists have found Earth life growing in acid,
in Antarctica and other extreme environments. But nothing topped last
week's news of a lake bacterium that scientists could train to thrive
on arsenic instead of phosphorous. Six major elements have long been
considered essential for life - carbon, hydrogen, nitrogen, oxygen,
phosphorus and sulfur. This changed that definition of life.
By making life more likely in extreme places, it increases the number
of planets that are potential homes for life, said Kaltenegger, who
also works at the Max Planck Institute in Germany.
Donald Brownlee, an astronomer at the University of Washington, is
less optimistic because he believes what's likely to be out there is
not going to be easy to find - or that meaningful. If it's out there,
he said, it's likely microbes that can't be seen easily from great
distances. Also, the different geologic and atmospheric forces on
planets may keep life from evolving into something complex or
intelligent, he said.
If life is going to be found, Mars is the most likely candidate. And
any life is probably underground where there is water, astronomers
say. Other possibilities include Jupiter's moon Europa and Saturn's
moons Enceladus and Titan.
There's also a chance that a telescope could spot a planet with an
atmosphere that suggests photosynthesis is occurring, Kaltenegger
said. And then there's the possibility of finding alien life on Earth,
perhaps in a meteorite, or something with an entirely different set of
DNA.
And finally, advanced aliens could find us or we could hear their
radio transmissions, McKay said. That's what the SETI Institute is
about, listening for intelligent life.
That's where Shostak puts his money behind his optimism. At his public
lectures, Shostak bets a cup of coffee for everyone in the audience
that scientists will find proof of alien life by about 2026. The odds,
he figures, have never been more in his favor.
More information:
NASA Astrobiology Institute: http://astrobiology.nasa.gov/ (http://www.google.com/url?sa=D&q=http://astrobiology.nasa.gov/&usg=AFQjCNHM9UV-6kNLFJB_R_nF6rOr5-4fMA)
SETI Institute: http://www.seti.org/ (http://www.google.com/url?sa=D&q=http://www.seti.org/&usg=AFQjCNHwWNy6mm71yfk0cfIKB2bgjF3vMQ)
Nature: http://www.nature.com/nature (http://www.google.com/url?sa=D&q=http://www.nature.com/nature&usg=AFQjCNGSnnJtjJTSxptgJkn-4BM7LJCEZQ)
©2010 The Associated Press. All rights reserved. This material may not
be published, broadcast, rewritten or redistributed.
"Evidence for ET is mounting daily, but not proven." December 8th,
2010. http://www.physorg.com/news/2010-12-evidence-mounting-daily-proven.html (http://www.google.com/url?sa=D&q=http://www.physorg.com/news/2010-12-evidence-mounting-daily-proven.html&usg=AFQjCNFgDtfbMg2yFEBIWkUJU5eoh9-vVQ)
December 8th, 2010 in Space & Earth / Space Exploration
(AP) -- Lately, a handful of new discoveries make it seem more likely
that we are not alone - that there is life somewhere else in the
universe.
In the past several days, scientists have reported there are three
times as many stars as they previously thought. Another group of
researchers discovered a microbe can live on arsenic, expanding our
understanding of how life can thrive under the harshest environments.
And earlier this year, astronomers for the first time said they'd
found a potentially habitable planet.
"The evidence is just getting stronger and stronger," said Carl
Pilcher, director of NASA's Astrobiology Institute, which studies the
origins, evolution and possibilities of life in the universe. "I think
anybody looking at this evidence is going to say, 'There's got to be
life out there.'"
A caveat: Since much of this research is new, scientists are still
debating how solid the conclusions are. Some scientists this week have
publicly criticized how NASA's arsenic-using microbe study was
conducted, questioning its validity.
Another reason not to get too excited is that the search for life
starts small - microscopically small - and then looks to evolution for
more. The first signs of life elsewhere are more likely to be closer
to slime mold than to ET. It can evolve from there.
Scientists have an equation that calculates the odds of civilized life
on another planet. But much of it includes factors that are pure
guesswork on less-than-astronomical factors, such as the likelihood of
the evolution of intelligence and how long civilizations last.
Stripped to its simplistic core - with the requirement for
intelligence and civilization removed - the calculations hinge on two
basic factors: How many places out there can support life? And how
hard is it for life to take root?
What last week's findings did was both increase the number of
potential homes for life and broaden the definition of what life is.
That means the probability for alien life is higher than ever before,
agree 10 scientists interviewed by The Associated Press.
Seth Shostak, senior astronomer at the SETI Institute in California,
ticks off the astronomical findings about planet abundance and
Earthbound discoveries about life's hardiness. "All of these have gone
in the direction of encouraging life out there and they didn't have
to."
Two new studies published online Wednesday in the journal Nature add
to the interest in weird planets outside our solar system, though they
don't exactly make a stronger case for life. One study found a super-
hot planet much bigger than Jupiter that seems to be full of carbon in
its atmosphere. In the other study, astronomers found a star with at
least four large young planets, challenging past assumptions that
there's a limit to how many huge planets a star system could have.
Scientists who looked for life were once dismissed as working on the
fringes of science. Now, Shostak said, it's the other way around. He
said that given the mounting evidence, to believe now that Earth is
the only place harboring life is essentially like believing in
miracles. "And astronomers tend not to believe in miracles."
Astronomers, however, do believe in proof. They don't have proof of
life yet. There's no green alien or even a bacterium that scientists
can point to and say it's alive and alien. Even that arsenic-munching
microbe discovered in Mono Lake in California isn't truly alien. It
was manipulated in the lab.
But, says NASA astrobiologist Chris McKay, who has worked on searches
for life on Mars and extreme places on Earth, "There are real things
we can point to and show that being optimistic about life elsewhere is
not silly."
First, there's the basic question of where such life might exist.
Until a few years ago, astronomers thought life was only likely to be
found on or around planets circling stars like our sun. So that's
where the search of life focused - on stars like ours.
That left out the universe's most common stars: red dwarfs, which are
smaller than our sun and dimmer. Up to 90 percent of the stars in the
universe are red dwarf stars. And astronomers assumed planets circling
them would be devoid of life.
But three years ago, NASA got the top experts in the field together.
They crunched numbers and realized that life could exist on planets
orbiting red dwarfs. The planets would have to be closer to their star
and wouldn't rotate as quickly as Earth. The scientists considered
habitability and found conditions near these small stars wouldn't be
similar to Earth but would still be acceptable for life.
That didn't just open up billions of new worlds, but many, many times
that.
Last week, a Yale University astronomer said he estimates there are
300 sextillion stars - triple the previous number. Lisa Kaltenegger of
Harvard University says scientists now believe that as many as half
the stars in our galaxy have planets that are two to 10 times the size
of Earth - "super Earths" which might sustain life.
Then the question is how many of those are in the so-called Goldilocks
zone - not too hot, not too cold. The discovery of such a planet was
announced in April, although some scientists are challenging that.
The other half of the equation is: How likely is life? Over the past
decade and a half, scientists have found Earth life growing in acid,
in Antarctica and other extreme environments. But nothing topped last
week's news of a lake bacterium that scientists could train to thrive
on arsenic instead of phosphorous. Six major elements have long been
considered essential for life - carbon, hydrogen, nitrogen, oxygen,
phosphorus and sulfur. This changed that definition of life.
By making life more likely in extreme places, it increases the number
of planets that are potential homes for life, said Kaltenegger, who
also works at the Max Planck Institute in Germany.
Donald Brownlee, an astronomer at the University of Washington, is
less optimistic because he believes what's likely to be out there is
not going to be easy to find - or that meaningful. If it's out there,
he said, it's likely microbes that can't be seen easily from great
distances. Also, the different geologic and atmospheric forces on
planets may keep life from evolving into something complex or
intelligent, he said.
If life is going to be found, Mars is the most likely candidate. And
any life is probably underground where there is water, astronomers
say. Other possibilities include Jupiter's moon Europa and Saturn's
moons Enceladus and Titan.
There's also a chance that a telescope could spot a planet with an
atmosphere that suggests photosynthesis is occurring, Kaltenegger
said. And then there's the possibility of finding alien life on Earth,
perhaps in a meteorite, or something with an entirely different set of
DNA.
And finally, advanced aliens could find us or we could hear their
radio transmissions, McKay said. That's what the SETI Institute is
about, listening for intelligent life.
That's where Shostak puts his money behind his optimism. At his public
lectures, Shostak bets a cup of coffee for everyone in the audience
that scientists will find proof of alien life by about 2026. The odds,
he figures, have never been more in his favor.
More information:
NASA Astrobiology Institute: http://astrobiology.nasa.gov/ (http://www.google.com/url?sa=D&q=http://astrobiology.nasa.gov/&usg=AFQjCNHM9UV-6kNLFJB_R_nF6rOr5-4fMA)
SETI Institute: http://www.seti.org/ (http://www.google.com/url?sa=D&q=http://www.seti.org/&usg=AFQjCNHwWNy6mm71yfk0cfIKB2bgjF3vMQ)
Nature: http://www.nature.com/nature (http://www.google.com/url?sa=D&q=http://www.nature.com/nature&usg=AFQjCNGSnnJtjJTSxptgJkn-4BM7LJCEZQ)
©2010 The Associated Press. All rights reserved. This material may not
be published, broadcast, rewritten or redistributed.
"Evidence for ET is mounting daily, but not proven." December 8th,
2010. http://www.physorg.com/news/2010-12-evidence-mounting-daily-proven.html (http://www.google.com/url?sa=D&q=http://www.physorg.com/news/2010-12-evidence-mounting-daily-proven.html&usg=AFQjCNFgDtfbMg2yFEBIWkUJU5eoh9-vVQ)