Post by auntym on Aug 26, 2014 13:50:31 GMT -6
www.startribune.com/science/272187201.html
Are odds in favor of extraterrestrial life?
Article by: GEORGE JOHNSON , New York Times
Updated: August 22, 2014
Almost 20 years ago, in the pages of an obscure publication called Bioastronomy News, two science giants argued over whether SETI — the Search for Extraterrestrial Intelligence — had a chance of succeeding. Carl Sagan, as eloquent as ever, gave his standard answer. With billions of stars in our galaxy, there must be other civilizations capable of transmitting electromagnetic waves. By scouring the sky with radio telescopes, we might intercept a signal.
But Sagan’s opponent, the great evolutionary biologist Ernst Mayr, thought the chances were close to zero. Against Sagan’s stellar billions, he posed his own astronomical numbers: Of the billions of species that have lived and died since life began, only one — Homo sapiens — had developed a science, a technology, and the curiosity to explore the stars. And that took about 3.5 billion years of evolution. High intelligence, Mayr concluded, must be extremely rare, here or anywhere. Earth’s most abundant life form is unicellular slime.
Since the debate with Sagan, more than 1,700 planets have been discovered beyond the solar system — 700 just this year. Astronomers recently estimated that one of every five sunlike stars in the Milky Way might be orbited by a world capable of supporting some kind of life.
That is about 40 billion potential habitats. But Mayr, who died in 2005 at the age of 100, probably wouldn’t have been impressed. By his reckoning, the odds would still be very low for anything much beyond slime worlds. No evidence has yet emerged to prove him wrong.
Maybe we’re just not looking hard enough. Since SETI began in the early 1960s, it has struggled for money to monitor even a fraction of the sky. In an online essay, Seth Shostak, senior astronomer at the SETI Institute, lamented how little has been allocated for the quest — a fraction of NASA’s budget.
CONTINUE READING: www.startribune.com/science/272187201.html
Are odds in favor of extraterrestrial life?
Article by: GEORGE JOHNSON , New York Times
Updated: August 22, 2014
Almost 20 years ago, in the pages of an obscure publication called Bioastronomy News, two science giants argued over whether SETI — the Search for Extraterrestrial Intelligence — had a chance of succeeding. Carl Sagan, as eloquent as ever, gave his standard answer. With billions of stars in our galaxy, there must be other civilizations capable of transmitting electromagnetic waves. By scouring the sky with radio telescopes, we might intercept a signal.
But Sagan’s opponent, the great evolutionary biologist Ernst Mayr, thought the chances were close to zero. Against Sagan’s stellar billions, he posed his own astronomical numbers: Of the billions of species that have lived and died since life began, only one — Homo sapiens — had developed a science, a technology, and the curiosity to explore the stars. And that took about 3.5 billion years of evolution. High intelligence, Mayr concluded, must be extremely rare, here or anywhere. Earth’s most abundant life form is unicellular slime.
Since the debate with Sagan, more than 1,700 planets have been discovered beyond the solar system — 700 just this year. Astronomers recently estimated that one of every five sunlike stars in the Milky Way might be orbited by a world capable of supporting some kind of life.
That is about 40 billion potential habitats. But Mayr, who died in 2005 at the age of 100, probably wouldn’t have been impressed. By his reckoning, the odds would still be very low for anything much beyond slime worlds. No evidence has yet emerged to prove him wrong.
Maybe we’re just not looking hard enough. Since SETI began in the early 1960s, it has struggled for money to monitor even a fraction of the sky. In an online essay, Seth Shostak, senior astronomer at the SETI Institute, lamented how little has been allocated for the quest — a fraction of NASA’s budget.
CONTINUE READING: www.startribune.com/science/272187201.html