Sunday, March 21, 2004
The I Ching (Classic of Changes or Book of Changes), also known as the Yi Jing, Yijing, or I Ging, is one of the Five Classics, the fundamental books of Confucianism. It is over 3000 years old (the symbols used in divination are over 5000 years old), making it both one of the oldest surviving books in the world, and one of the oldest forms of divination. It is by far the most popular spiritual resource and oracle in Asia.
Sunday, March 14, 2004
This has some useful diagnostic flow charts. Informative site referencing DSM-IV.
http://www.psyweb.com/Mdisord/DSM_IV/dsm_iv.html
http://www.psyweb.com/Mdisord/DSM_IV/dsm_iv.html
Friday, March 12, 2004
http://www.washingtonpost.com/ac2/wp-dyn?pagename=article&node=&contentId=A53203-2004Feb18¬Found=true
Ike and the Alien Ambassadors
The Whole Tooth About the President's Extraterrestrial Encounter
By Peter Carlson
Washington Post Staff Writer
Thursday, February 19, 2004; Page C01
Fifty years ago tomorrow -- on Feb. 20, 1954 -- President Dwight Eisenhower interrupted his vacation in Palm Springs, Calif., to make a secret nocturnal trip to a nearby Air Force base to meet two extraterrestrial aliens.
Or maybe not. Maybe Ike just went to the dentist. There's some dispute about this.
The Ike-met-with-ETs theory is advanced by Michael Salla, a former American University professor who now runs the Peace Ambassador Program at AU's Center for Global Peace.
The Ike-went-to-the-dentist theory is advanced by the folks at the Dwight D. Eisenhower Library in Abilene, Kan. And by James M. Mixson, a dentist, professor of dentistry and historian of presidential dental work.
Just to make things more intriguing: On the night in question, the Associated Press reported this: "Pres. Eisenhower died tonight of a heart attack in Palm Springs."
Two minutes later, the AP retracted that bulletin and reported that Ike was still alive.
Indeed, Ike was alive. And he continued living until 1969. But in the decades since his death, his activities on the night of Feb. 20, 1954, have become fodder for strange theories about alien beings.
Some facts are beyond dispute: Eisenhower was on a golf vacation in Palm Springs on Feb. 20, 1954. After dinner that night, he made an unscheduled departure from the Smoking Tree Ranch, where he was staying. The next morning, he attended a church service in Los Angeles. Also that morning, his spokesman announced to the press that Ike had visited a dentist the previous night because he'd chipped a tooth while eating a chicken wing at dinner.
Salla, who has a PhD in government from the University of Queensland in his native Australia, doesn't believe it. He figures the dentist trip is just a cover story. He believes Ike went to Edwards Air Force Base, where he met with two ETs with white hair, pale blue eyes and colorless lips.
These aliens -- nicknamed "Nordics" in UFO circles because they resemble Scandinavian humans -- traveled to Edwards from another solar system in a flying saucer and, Salla says, they spoke to Eisenhower.
"There was telepathic communication," says Salla, 45, as he sits in his suburban Falls Church living room. "It's as though you're hearing a person but they're not speaking."
The "Nordics" offered to share their superior technology and their spiritual wisdom with Ike if he would agree to eliminate America's nuclear weapons.
"They were afraid we might blow up some of our nuclear technology," Salla says, "and apparently that does something to time and space and it impacts on extraterrestrial races on other planets."
Ike declined the ETs' offer, Salla says, because he did not want to give up the nukes.
Sometime later in 1954, Ike reached a deal with another race of extraterrestrials, known as the "Greys" -- allowing them to capture earthling cattle and humans for medical experiments, provided that they returned the humans safely home. Since then, Salla says, the "Greys" have kidnapped "millions" of humans.
Salla, author of "The Hero's Journey Toward a Second American Century," published his ET theories in his new book, "Exopolitics: Political Implications of the Extraterrestrial Presence" and in an article on his "Exopolitics" Web site (www.exopolitics.org).
For much of the '90s, Salla studied conflict resolution and tried unsuccessfully to apply that knowledge to prevent war in East Timor and the Balkans, he says. Frustrated, he began looking for an extraterrestrial connection to human misery and, he says, he found evidence of ET visitations -- including the Ike encounter -- on the Internet.
"There's a lot of stuff on the Internet," he says, "and I just went around and pieced it together."
Meanwhile, he taught at the School of International Service at American University. In 2003 he founded the university's Peace Ambassador Program, described on the AU Web site as a "summer program that combines study, meditative practices, and prayer ceremonies at selected Washington DC sites aimed at promoting individual self-empowerment and Divine Governance in Washington DC."
Salla stresses that his ET research is not connected with his work at AU's Center for Global Peace. The folks at the Center for Global Peace are also quite eager to stress that fact.
"The research that Michael Salla is doing is not research that he is conducting on behalf of the center or in collaboration with the center," says Betty Sitka, associate director of the Center for Global Peace. "This is his own personal research."
Meanwhile, the question remains: Did Ike really meet with ETs 50 years ago?
"Not to our knowledge," says Jim Leyerzapf, an archivist at the Eisenhower Library. "There's nothing in the archives that indicates that."
Then Leyerzapf bursts out laughing.
He has heard this theory before. "We've had so many requests on that subject that we have a person who specializes in this."
That person is archivist Herb Pankratz.
"He specialized in transportation," Leyerzapf says, "and we decided to add UFOs to that. He does trains, planes, automobiles -- and flying saucers."
The library fielded dozens of questions about the alleged Ike-ET meeting in the late '80s and early '90s, when several UFO books advanced the theory, Pankratz says.
"It's interesting how these stories have changed," Pankratz noted in an e-mail. "Initially, the accounts claimed the President made a secret trip to Edwards Air Force Base to view the remains of aliens who had crashed at Roswell, N.M., in 1947. Later stories then claimed he had actually visited with live aliens."
Pankratz doesn't buy either theory. He believes the dentist story, and he cites James Mixson, the dental historian and professor at the University of Missouri-Kansas City School of Dentistry. Mixson's article "A History of Dwight D. Eisenhower's Oral Health" -- published in the November 1995 issue of the Bulletin of the History of Dentistry -- is the definitive work on Ike's teeth.
Citing the U.S. surgeon general's records on Ike's medical and dental history, opened to researchers in 1991, Mixson reported that on the fateful night of Feb. 20, 1954, Ike chipped the porcelain cap of his "upper left central incisor" and it was repaired by Dr. Francis A. Purcell.
Alas, Purcell is unavailable for comment. He died in 1974, according to Pankratz.
"The lack of a dental record from Purcell's office," Mixson wrote, "has helped fuel belief in this UFO encounter."
But, Mixson quickly added, "the President had well-documented difficulties with this crown."
Indeed, the crown, which was installed in July 1952, was chipped and repaired in December 1952, the February in question, and again in July 1954, when the president's dentist, Col. James M. Fairchild, replaced it with a "thin cast gold/platinum thimble crown."
That may be more than you wanted to know about Ike's dental work. If not, Mixson goes on at some length, quoting a long, lyrical passage written by Fairchild on this troublesome presidential incisor.
Meanwhile, there's another perplexing question: Why did the AP report that Ike died that night?
"Somebody was fooling around and it went out," Pankratz says. "It wasn't supposed to go out but it did."
Ike never made any public statement about meeting ETs, Pankratz says. But did he perhaps spill the beans to his family? Ike's son, John S.D. Eisenhower, is a retired Army brigadier general and author of several books on history, including "General Ike: A Personal Reminiscence."
Asked via e-mail if his father had ever mentioned meeting with aliens, Eisenhower responded with a short but emphatic reply: "No." He declined to comment further.
© 2004 The Washington Post Company
Ike and the Alien Ambassadors
The Whole Tooth About the President's Extraterrestrial Encounter
By Peter Carlson
Washington Post Staff Writer
Thursday, February 19, 2004; Page C01
Fifty years ago tomorrow -- on Feb. 20, 1954 -- President Dwight Eisenhower interrupted his vacation in Palm Springs, Calif., to make a secret nocturnal trip to a nearby Air Force base to meet two extraterrestrial aliens.
Or maybe not. Maybe Ike just went to the dentist. There's some dispute about this.
The Ike-met-with-ETs theory is advanced by Michael Salla, a former American University professor who now runs the Peace Ambassador Program at AU's Center for Global Peace.
The Ike-went-to-the-dentist theory is advanced by the folks at the Dwight D. Eisenhower Library in Abilene, Kan. And by James M. Mixson, a dentist, professor of dentistry and historian of presidential dental work.
Just to make things more intriguing: On the night in question, the Associated Press reported this: "Pres. Eisenhower died tonight of a heart attack in Palm Springs."
Two minutes later, the AP retracted that bulletin and reported that Ike was still alive.
Indeed, Ike was alive. And he continued living until 1969. But in the decades since his death, his activities on the night of Feb. 20, 1954, have become fodder for strange theories about alien beings.
Some facts are beyond dispute: Eisenhower was on a golf vacation in Palm Springs on Feb. 20, 1954. After dinner that night, he made an unscheduled departure from the Smoking Tree Ranch, where he was staying. The next morning, he attended a church service in Los Angeles. Also that morning, his spokesman announced to the press that Ike had visited a dentist the previous night because he'd chipped a tooth while eating a chicken wing at dinner.
Salla, who has a PhD in government from the University of Queensland in his native Australia, doesn't believe it. He figures the dentist trip is just a cover story. He believes Ike went to Edwards Air Force Base, where he met with two ETs with white hair, pale blue eyes and colorless lips.
These aliens -- nicknamed "Nordics" in UFO circles because they resemble Scandinavian humans -- traveled to Edwards from another solar system in a flying saucer and, Salla says, they spoke to Eisenhower.
"There was telepathic communication," says Salla, 45, as he sits in his suburban Falls Church living room. "It's as though you're hearing a person but they're not speaking."
The "Nordics" offered to share their superior technology and their spiritual wisdom with Ike if he would agree to eliminate America's nuclear weapons.
"They were afraid we might blow up some of our nuclear technology," Salla says, "and apparently that does something to time and space and it impacts on extraterrestrial races on other planets."
Ike declined the ETs' offer, Salla says, because he did not want to give up the nukes.
Sometime later in 1954, Ike reached a deal with another race of extraterrestrials, known as the "Greys" -- allowing them to capture earthling cattle and humans for medical experiments, provided that they returned the humans safely home. Since then, Salla says, the "Greys" have kidnapped "millions" of humans.
Salla, author of "The Hero's Journey Toward a Second American Century," published his ET theories in his new book, "Exopolitics: Political Implications of the Extraterrestrial Presence" and in an article on his "Exopolitics" Web site (www.exopolitics.org).
For much of the '90s, Salla studied conflict resolution and tried unsuccessfully to apply that knowledge to prevent war in East Timor and the Balkans, he says. Frustrated, he began looking for an extraterrestrial connection to human misery and, he says, he found evidence of ET visitations -- including the Ike encounter -- on the Internet.
"There's a lot of stuff on the Internet," he says, "and I just went around and pieced it together."
Meanwhile, he taught at the School of International Service at American University. In 2003 he founded the university's Peace Ambassador Program, described on the AU Web site as a "summer program that combines study, meditative practices, and prayer ceremonies at selected Washington DC sites aimed at promoting individual self-empowerment and Divine Governance in Washington DC."
Salla stresses that his ET research is not connected with his work at AU's Center for Global Peace. The folks at the Center for Global Peace are also quite eager to stress that fact.
"The research that Michael Salla is doing is not research that he is conducting on behalf of the center or in collaboration with the center," says Betty Sitka, associate director of the Center for Global Peace. "This is his own personal research."
Meanwhile, the question remains: Did Ike really meet with ETs 50 years ago?
"Not to our knowledge," says Jim Leyerzapf, an archivist at the Eisenhower Library. "There's nothing in the archives that indicates that."
Then Leyerzapf bursts out laughing.
He has heard this theory before. "We've had so many requests on that subject that we have a person who specializes in this."
That person is archivist Herb Pankratz.
"He specialized in transportation," Leyerzapf says, "and we decided to add UFOs to that. He does trains, planes, automobiles -- and flying saucers."
The library fielded dozens of questions about the alleged Ike-ET meeting in the late '80s and early '90s, when several UFO books advanced the theory, Pankratz says.
"It's interesting how these stories have changed," Pankratz noted in an e-mail. "Initially, the accounts claimed the President made a secret trip to Edwards Air Force Base to view the remains of aliens who had crashed at Roswell, N.M., in 1947. Later stories then claimed he had actually visited with live aliens."
Pankratz doesn't buy either theory. He believes the dentist story, and he cites James Mixson, the dental historian and professor at the University of Missouri-Kansas City School of Dentistry. Mixson's article "A History of Dwight D. Eisenhower's Oral Health" -- published in the November 1995 issue of the Bulletin of the History of Dentistry -- is the definitive work on Ike's teeth.
Citing the U.S. surgeon general's records on Ike's medical and dental history, opened to researchers in 1991, Mixson reported that on the fateful night of Feb. 20, 1954, Ike chipped the porcelain cap of his "upper left central incisor" and it was repaired by Dr. Francis A. Purcell.
Alas, Purcell is unavailable for comment. He died in 1974, according to Pankratz.
"The lack of a dental record from Purcell's office," Mixson wrote, "has helped fuel belief in this UFO encounter."
But, Mixson quickly added, "the President had well-documented difficulties with this crown."
Indeed, the crown, which was installed in July 1952, was chipped and repaired in December 1952, the February in question, and again in July 1954, when the president's dentist, Col. James M. Fairchild, replaced it with a "thin cast gold/platinum thimble crown."
That may be more than you wanted to know about Ike's dental work. If not, Mixson goes on at some length, quoting a long, lyrical passage written by Fairchild on this troublesome presidential incisor.
Meanwhile, there's another perplexing question: Why did the AP report that Ike died that night?
"Somebody was fooling around and it went out," Pankratz says. "It wasn't supposed to go out but it did."
Ike never made any public statement about meeting ETs, Pankratz says. But did he perhaps spill the beans to his family? Ike's son, John S.D. Eisenhower, is a retired Army brigadier general and author of several books on history, including "General Ike: A Personal Reminiscence."
Asked via e-mail if his father had ever mentioned meeting with aliens, Eisenhower responded with a short but emphatic reply: "No." He declined to comment further.
© 2004 The Washington Post Company
http://www.chriswetherell.com/elf/
Generate your Elf Name
http://www.chriswetherell.com/hobbit/Default.asp
and generate your Hobbit Name
Generate your Elf Name
http://www.chriswetherell.com/hobbit/Default.asp
and generate your Hobbit Name
http://www.mufor.org/moon.htm
http://www.quiknet.com/~maxsmoke/moonstuff.html
back in the 1970's two Soviet scientists from the Soviet academy of sciences proposed the theory that the moon was a Hollow Alien Spaceship placed in orbit around the earth.
There has often been speculation, even amongst Astronomers and scientists, that Phobos, one of the Moons of Mars may be Hollow. Its strange orbit is cited as one of the reasons - plus many strange markings on it and a "huge" crater which covers about 1/4 of its surface area
http://www.quiknet.com/~maxsmoke/moonstuff.html
back in the 1970's two Soviet scientists from the Soviet academy of sciences proposed the theory that the moon was a Hollow Alien Spaceship placed in orbit around the earth.
There has often been speculation, even amongst Astronomers and scientists, that Phobos, one of the Moons of Mars may be Hollow. Its strange orbit is cited as one of the reasons - plus many strange markings on it and a "huge" crater which covers about 1/4 of its surface area
http://www.anomalous-images.com/moon.html
THE SHARD
The Shard is an obvious structure which rises above the Moon's surface by more than a mile. Its overall irregular spindly shape (containing a regular geometric pattern) with constricted nodes and swollen internodes, if natural, has got to be a wonder of the Universe. No known natural process can explain such a structure. Computer enhancement with about 190 feet (60 meters) resolution shows an irregular outline with more reflective and less reflective surfaces. The amount of sunlight reflecting from parts of the Shard indicate a composition inconsistent with that of most natural substances. Only crystal facets and glass can reflect that much light (polished metallic surfaces are unnatural). Single crystals the size of city blocks are currently unknown. I concur with Hoagland that the Shard may be a highly eroded remnant of some sort of artificial structure made of glass-like material. Other larger structures and their reflectivity in the area support this theory.
THE SHARD
The Shard is an obvious structure which rises above the Moon's surface by more than a mile. Its overall irregular spindly shape (containing a regular geometric pattern) with constricted nodes and swollen internodes, if natural, has got to be a wonder of the Universe. No known natural process can explain such a structure. Computer enhancement with about 190 feet (60 meters) resolution shows an irregular outline with more reflective and less reflective surfaces. The amount of sunlight reflecting from parts of the Shard indicate a composition inconsistent with that of most natural substances. Only crystal facets and glass can reflect that much light (polished metallic surfaces are unnatural). Single crystals the size of city blocks are currently unknown. I concur with Hoagland that the Shard may be a highly eroded remnant of some sort of artificial structure made of glass-like material. Other larger structures and their reflectivity in the area support this theory.
Friday, March 05, 2004
Thursday, March 04, 2004
There are two basic types of string theories: those with closed string loops that can break into open strings, shown above, and those with closed string loops that can't break into open strings.
Think of a guitar string that has been tuned by stretching the string under tension across the guitar. Depending on how the string is plucked and how much tension is in the string, different musical notes will be created by the string. These musical notes could be said to be excitation modes of that guitar string under tension.
In a similar manner, in string theory, the elementary particles we observe in particle accelerators could be thought of as the "musical notes" or excitation modes of elementary strings.
In string theory, as in guitar playing, the string must be stretched under tension in order to become excited. However, the strings in string theory are floating in spacetime, they aren't tied down to a guitar. Nonetheless, they have tension. The string tension in string theory is denoted by the quantity 1/(2 p a'), where a' is pronounced "alpha prime"and is equal to the square of the string length scale.
If string theory is to be a theory of quantum gravity, then the average size of a string should be somewhere near the length scale of quantum gravity, called the Planck length, which is about 10-33 centimeters, or about a millionth of a billionth of a billionth of a billionth of a centimeter. Unfortunately, this means that strings are way too small to see by current or expected particle physics technology (or financing!!) and so string theorists must devise more clever methods to test the theory than just looking for little strings in particle experiments.
String theories are classified according to whether or not the strings are required to be closed loops, and whether or not the particle spectrum includes fermions. In order to include fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particle that transmits a force) there is a corresponding fermion (particle that makes up matter). So supersymmetry relates the particles that transmit forces to the particles that make up matter.
Supersymmetric partners to to currently known particles have not been observed in particle experiments, but theorists believe this is because supersymmetric particles are too massive to be detected at current accelerators. Particle accelerators could be on the verge of finding evidence for high energy supersymmetry in the next decade. Evidence for supersymmetry at high energy would be compelling evidence that string theory was a good mathematical model for Nature at the smallest distance scales.
There are several ways theorists can build string theories. Start with the elementary ingredient: a wiggling tiny string. Next decide: should it be an open string or a closed string? Then ask: will I settle for only bosons ( particles that transmit forces) or will I ask for fermions, too (particles that make up matter)? (Remember that in string theory, a particle is like a note played on the string.)
If the answer to the last question is "Bosons only, please!" then one gets bosonic string theory. If the answer is "No, I demand that matter exist!" then we wind up needing supersymmetry, which means an equal matching between bosons (particles that transmit forces) and fermions (particles that make up matter). A supersymmetric string theory is called a superstring theory. There are five kinds of superstring theories, shown in the table below.
The final question for making a string theory should be: can I do quantum mechanics sensibly? For bosonic strings, this question is only answered in the affirmative if the spacetime dimensions number 26. For superstrings we can whittle it down to 10. How we get down to the four spacetime dimensions we observe in our world is another story.
Think of a guitar string that has been tuned by stretching the string under tension across the guitar. Depending on how the string is plucked and how much tension is in the string, different musical notes will be created by the string. These musical notes could be said to be excitation modes of that guitar string under tension.
In a similar manner, in string theory, the elementary particles we observe in particle accelerators could be thought of as the "musical notes" or excitation modes of elementary strings.
In string theory, as in guitar playing, the string must be stretched under tension in order to become excited. However, the strings in string theory are floating in spacetime, they aren't tied down to a guitar. Nonetheless, they have tension. The string tension in string theory is denoted by the quantity 1/(2 p a'), where a' is pronounced "alpha prime"and is equal to the square of the string length scale.
If string theory is to be a theory of quantum gravity, then the average size of a string should be somewhere near the length scale of quantum gravity, called the Planck length, which is about 10-33 centimeters, or about a millionth of a billionth of a billionth of a billionth of a centimeter. Unfortunately, this means that strings are way too small to see by current or expected particle physics technology (or financing!!) and so string theorists must devise more clever methods to test the theory than just looking for little strings in particle experiments.
String theories are classified according to whether or not the strings are required to be closed loops, and whether or not the particle spectrum includes fermions. In order to include fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particle that transmits a force) there is a corresponding fermion (particle that makes up matter). So supersymmetry relates the particles that transmit forces to the particles that make up matter.
Supersymmetric partners to to currently known particles have not been observed in particle experiments, but theorists believe this is because supersymmetric particles are too massive to be detected at current accelerators. Particle accelerators could be on the verge of finding evidence for high energy supersymmetry in the next decade. Evidence for supersymmetry at high energy would be compelling evidence that string theory was a good mathematical model for Nature at the smallest distance scales.
There are several ways theorists can build string theories. Start with the elementary ingredient: a wiggling tiny string. Next decide: should it be an open string or a closed string? Then ask: will I settle for only bosons ( particles that transmit forces) or will I ask for fermions, too (particles that make up matter)? (Remember that in string theory, a particle is like a note played on the string.)
If the answer to the last question is "Bosons only, please!" then one gets bosonic string theory. If the answer is "No, I demand that matter exist!" then we wind up needing supersymmetry, which means an equal matching between bosons (particles that transmit forces) and fermions (particles that make up matter). A supersymmetric string theory is called a superstring theory. There are five kinds of superstring theories, shown in the table below.
The final question for making a string theory should be: can I do quantum mechanics sensibly? For bosonic strings, this question is only answered in the affirmative if the spacetime dimensions number 26. For superstrings we can whittle it down to 10. How we get down to the four spacetime dimensions we observe in our world is another story.
Tuesday, March 02, 2004
Odds of Complex Life: Great Debates Part III
Summary: Microbial life, at least, may be common in our stellar neighborhood and even may be present on other planets in our Solar System. That being the premise, the probability of complex life elsewhere is then dependent on the probability of the transition from slime to civilization. It happened here, so why not elsewhere? Do you think that complex life should develop on a sizeable fraction of worlds around other stars?
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Great Debates: Part III
By: Astrobiology Magazine staff writer
Odds of Complex Life
The debate about the "Rare Earth" hypothesis continues today with a discussion about complex life and the possibility of its occurrence in the universe. Complex life is generally considered any living thing with multiple cells - as opposed to single celled, microbial life - and, on Earth anyway, includes everything from the simplest slime molds to human beings.
The participants in today's debate are (click photos for larger image):
Debate moderator Michael Meyer, the Senior Scientist for astrobiology at NASA Headquarters and Program Scientist for the Mars 2001 Odyssey Mission. Donald Brownlee, co-author of "Rare Earth," and Professor of Astronomy of the University of Washington in Seattle.
Frank Drake, Chairman of the Board of Trustees of the SETI Institute, and Professor of Astronomy and Astrophysics at the University of California at Santa Cruz. David Grinspoon, Principal Scientist in the Department of Space Studies, Southwest Research Institute in Boulder, Colorado, and author of the forthcoming book "Lonely Planets: The Natural Philosophy of Alien Life".
Christopher McKay, planetary scientist with the Space Science Division of NASA Ames Research Center. Peter Ward, co-author of "Rare Earth," and Professor of Geological Sciences at the University of Washington in Seattle.
Simon Conway Morris, professor of Evolutionary Palaeobiology at the University of Cambridge in England.
Michael Meyer - I presume that we are in agreement that microbial life, at least, may be common in our stellar neighborhood and even may be present on other planets in our Solar System. That being the premise, the probability of complex life elsewhere is then dependent on the probability of the transition from slime to civilization. It happened here, so why not elsewhere? Do you think that complex life should develop on a sizeable fraction of worlds around other stars?
"As David Grinspoon pointed out earlier, the Earth is our only example of planetary life. This makes it difficult to unravel what is universal and what is accidental about the nature and history of life." -Christopher McKay
Christopher McKay: As David Grinspoon pointed out earlier, the Earth is our only example of planetary life. This makes it difficult to unravel what is universal and what is accidental about the nature and history of life. Still, one data point is better than none, and when we look at the question of complex life, our one data point seems to say that complex life arose as a result of the rise of free oxygen. If we take this as being generally true, then we can ask the geophysical question: On what types of planets will free oxygen arise and how long will it take to reach high enough levels?
On Earth it took billions of years for oxygen to rise to present levels. Partly this is because the Earth is efficient at recycling by plate tectonics. This recycling keeps the Earth habitable by cycling the essential elements, but it also would have been a barrier to the build up of oxygen. Earth probably is not the best possible planet for complex life development, since less plate tectonics would allow a faster rate of oxygen build up.
Mars took this to the extreme. With no plate tectonics, a shallow ocean, and only 38% of the Earth's gravity, Mars might have built up oxygen much faster than the Earth. But the lack of plate tectonics doomed Mars to lose its atmosphere through mineralization. We might find that complex life arose on Mars only to be extinguished later. Perhaps the optimal planet for complex life would be an intermediate between Earth and Mars.
There may be a range of planet types on which oxygen could arise - and therefore complex life. I would hazard a guess that most - maybe two-thirds - of terrestrial planets with life go on to develop complex life at some stage of their history. An optimist's view.
Simon Conway Morris: The problem in my view is, why did complex life take so long to evolve on Earth? Evidence from oxygen data is frankly equivocal. Maybe the redox state of the Earth's mantle was peculiar in comparison with other similar planets. Alternatively, ocean chemistry may have put the lid on things. There could be other dimensions that could explain why there was such a brake on the evolution of complex life - why there were no Meso-Proterozoic dry martinis, but on the other hand, once microbes, then NASA.
David Grinspoon: Planetary biospheres are complex entities whose histories are fraught with contingency, accident, and luck. Therefore, the time it took for complex life to arise on Earth is probably much faster than some and much slower than others. We can't stand a mystery without a chief suspect, so we pin the rise of complex life on the rise of oxygen. This may well have factored in, but as Chris pointed out, there is no reason to believe that oxygen rose on Earth as quickly as it might have elsewhere. The rate of plate tectonics is one variable that will change atmospheric history - there are countless others. For example, if Earth had formed less rich in iron, then oxygen would have risen much more quickly because there would not have been as much iron to devour the oxygen. So in other planetary systems that are less metal-rich, creatures might have evolved to levels far beyond our current state.
"Planetary biospheres are complex entities whose histories are fraught with contingency, accident, and luck." -David Grinspoon
Image Credit: NASA
Peter Ward: On Earth, evolution has undergone a progressive development of ever more complex and sophisticated forms leading ultimately to human intelligence. Complex life - and even intelligence - could conceivably arise faster than it did on Earth. A planet could go from an abiotic state to a civilization in 100 million years, as compared to the nearly 4 billion years it took on Earth. Evolution on Earth has been affected by chance events, such as the configuration of the continents produced by continental drift. Furthermore, I believe that the way the solar system was produced, with its characteristic number and planetary positions, may have had a great impact on the history of life here.
It has always been assumed that attaining the evolutionary grade we call animals would be the final and decisive step. Once we are at this level of evolution, a long and continuous progression toward intelligence should occur. However, recent research shows that while attaining the stage of animal life is one thing, maintaining that level is quite another. The geologic record has shown that once evolved, complex life is subject to an unending succession of planetary disasters, creating what are known as mass extinction events. These rare but devastating events can reset the evolutionary timetable and destroy complex life while sparing simpler life forms. Such discoveries suggest that the conditions allowing the rise and existence of complex life are far more rigorous than are those for life's formation. On some planets, then, life might arise and animals eventually evolve - only to be soon destroyed by a global catastrophe.
Frank Drake: The Earth's fossil record is quite clear in showing that the complexity of the central nervous system - particularly the capabilities of the brain - has steadily increased in the course of evolution. Even the mass extinctions did not set back this steady increase in brain size. It can be argued that extinction events expedite the development of cognitive abilities, since those creatures with superior brains are better able to save themselves from the sudden change in their environment. Thus smarter creatures are selected, and the growth of intelligence accelerates.
We see this effect in all varieties of animals -- it is not a fluke that has occurred in some small sub-set of animal life. This picture suggests strongly that, given enough time, a biota can evolve not just one intelligent species, but many. So complex life should occur abundantly.
There is a claim that "among the millions of species which have developed on Earth, only one became intelligent, so intelligence must be a very, very rare event." This is a textbook example of a wrong logical conclusion. All planets in time may produce one or more intelligent species, but they will not appear simultaneously. One will be first. It will look around and find it is the only intelligent species. Should it be surprised? No! Of course the first one will be alone. Its uniqueness - in principal temporary - says nothing about the ability of the biota to produce one or more intelligent species.
If we assume that Earths are common, and that usually there is enough time to evolve an intelligent species before nature tramples on the biota, then the optimistic view is that new systems of intelligent, technology-using creatures appear about once per year. Based on an extrapolation of our own experience, let's make a guess that a civilization's technology is detectable after 10,000 years. In that case, there are at least 10,000 detectable civilizations out there. This is a heady result, and very encouraging to SETI people. On the other hand, taking into account the number and distribution of stars in space, it implies that the nearest detectable civilizations are about 1,000 light years away, and only one in ten million stars may have a detectable civilization. These last numbers create a daunting challenge to those who construct instruments and projects to search for extraterrestrial intelligence. No actual observing program carried out so far has come anywhere close to meeting the requirement of detecting reasonable signals from a distance of 1,000 light years, or of studying 10 million stars with high sensitivity.
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