Life Out There
Gazing Afar for Other Earths, and Other Beings
By DENNIS OVERBYE
Published: January 30, 2011
MOFFETT FIELD, Calif. — In a building at NASA’s Ames Research Center here, computers are sifting and resifting the light from 156,000 stars, seeking to find in the flickering of distant suns the first hints that humanity is not alone in the universe.
Combing 156,000 Stars
Articles in this series will examine the search for Earth-like planets and for new forms of life in the universe.
William Borucki, lead scientist for the Kepler satellite observatory, launched in 2009.
The stars are being monitored by a $600 million satellite observatory named Kepler, whose job is to conduct a kind of Gallup poll of worlds in the cosmos. On Wednesday, Kepler’s astronomers are scheduled to unveil a closely kept list of 400 stars that are their brightest and best bets so far for harboring planets, some of which could turn out to be the smallest and most Earth-like worlds discovered out there to date. They represent the first glimpse of riches to come in a quest that is as old as the imagination and as new as the iPad.
Over the next two or three years, as Kepler continues to stare and sift, astronomers say, it will be able to detect planets in the “Goldilocks” zones, where it is neither too hot nor too cold for liquid water.
“What we want is to find life,” said Geoffrey Marcy, an astronomer at the University of California, Berkeley, who is part of the Kepler team.
William Borucki, 72, the lead scientist, who has spent the last 20 years getting Kepler off the ground, said recently in an interview in his office: “I’ve argued that Kepler is more important than the Hubble Space Telescope. We provide the data mankind needs to move out into space.”
These are science-fiction times. Kepler is only the first step in a process that experts agree will take decades. Both NASA and the European Space Agency have laid plans for a multidecade quest — employing ever more sophisticated and expensive spacecraft — for planets and life beyond Earth.
A roving robot laboratory named Curiosity will depart for Mars on a $2.5 billion mission this fall. Astronomers argue whether the next such mission should go to Jupiter’s moon Europa, with its subsurface ocean; Saturn’s moon Titan, which is coated with a methane slush; or another of Saturn’s moons, Enceladus, which is spouting geysers of water from its interior.
Right now, humans cannot even summon the money or political will to get back to the Moon, let alone set sail for another star. It would take 300,000 years for Voyager 1, now on the way out of the solar system at 39,000 miles per hour, to travel the 20 light-years, or 120 trillion miles, to Gliese 581, one of the nearest planetary systems; Kepler’s planets are from 500 to 3,000 light-years away. NASA and other organizations, like the Planetary Society, have experimented with devices like solar sails, in which a craft is pushed by sunlight or a powerful laser, and ion drives, in which high-energy particles do the propelling.
This is more than just an intellectual exercise, scientists say. Traditional religious images of ourselves as God’s creatures, or even of God, could be in for a rough time if we ever discover pond scum living by completely alien chemical rules on some moon or planet, let alone the Borg — the alien race ruled by a collective mind on “Star Trek” — inhabiting some distant realm.
Moreover, as astronomers keep reminding us, humanity will eventually lose Earth as its home, whether because of global warming or the ultimate plague or a killer asteroid or the Sun’s inevitable demise. Before then, if we want the universe to remember us or even know we were here, we need to get away.
It was only in 1995 that a team of Swiss astronomers led by Michel Mayor of the Geneva Observatory discovered the first planet of another Sun-like star using what is now known as the “wobble” method. A planet gives its star a little gravitational tug as it goes around, causing the star to go back and forth, or wobble, a little as both star and planet circle the same center of gravity. They detected a wobble in the motion of the star 51 Pegasi as an object about half the mass of Jupiter whipped around it every four days.
Like Olives in a Martini Glass
Over the next decade, Dr. Mayor’s group and another planet-hunting team led by Dr. Marcy and R. Paul Butler of the Carnegie Institution leapfrogged each other in finding exoplanets, as they are called. More and more astronomers have joined the hunt, discovering smaller and smaller planets. Astronomers have recorded direct images of four planets swirling like olives in a martini glass around a star known as HR 8799, 130 light-years from Earth in the constellation Pegasus, and another circling Fomalhaut, only 25 light-years from Earth, in the constellation Piscis Austrinus.
There are now more than 500 planets listed on the Jet Propulsion Laboratory’s PlanetQuest Web site. None are habitable.
Among them is the so-called Styrofoam planet — an early trophy of Kepler’s — a planet that is again half as large as Jupiter, but so puffed up by the heat of its star that it is only one-tenth as dense. Another is a planet composed almost entirely of superheated water and sometimes called the Steam World; it is known as Gliese 1214b, about 40 light-years from here in the constellation Ophiuchus.
Last year, a team of American astronomers announced that they had discovered a Goldilocks planet orbiting a dim red dwarf star at just the right distance to harbor water on its surface, making it a potential site for life. Gliese 581g, as it is known, is part of the Gliese 581 system 20 light-years from here, in Libra. But then the Swiss astronomers who first spotted that system were not able to find the Goldilocks planet in their own data, causing many astronomers, but not its discoverers, to doubt that the friendly 581g was real.
The Kepler project grew out of Mr. Borucki’s lifelong love of space.
Mr. Borucki grew up in a small town in Wisconsin, shooting homemade rockets into the sky and praying that they did not hit a neighbor’s cow. “As a kid, this is what you wanted to do,” he said.
After getting a master’s degree in physics from the University of Wisconsin, he went to work on the Apollo Moon program, becoming an expert in precise measurements of light. In 1984, he suggested that such measurements could be used to look for planets.
The idea is that a planet passing in front of its star would block a little of its light — very little. In the case of the Earth, the dip would amount to 84 parts per million in the Sun’s light — less than a hundredth of a percent.
In 1993, when Mr. Borucki and his collaborators proposed building a satellite to do such measurements, NASA said, “If doable, it’s fabulous,” recalled David Koch of the University of Wisconsin, Mr. Borucki’s longtime collaborator. But NASA did not think detectors could be so precise.
NASA rejected their proposal a year later, then again two years after that. “It’s a wonderful thing to have someone tell you over and over again everything that is wrong with your experiment,” Mr. Borucki said. That was the road to improvement.
Peter DaSilva for The New York Times
In 1998, NASA turned the scientists down again, but gave them half a million dollars to spend on lab work. The Kepler mission finally got the nod from NASA in 2001, but with a twist. The Ames Research Center wound up handing over management of the mission, at least until the launching, to the Jet Propulsion Laboratory in Pasadena, Calif., which developed the Vikings and Voyagers. “Here we had been competing against J.P.L. all these years,” Dr. Koch said. “We got over that.” Control has since reverted to Ames.
Kepler was launched from Cape Canaveral into an orbit around the Sun on March 6, 2009. Its gaze is fixed on a patch of sky about 20 full moons across near the Northern Cross, in the constellations Cygnus and Lyra, containing about 4.5 million stars. That is the neighborhood for Kepler’s cosmic census. The job is simply to measure the brightness of 156,000 of those stars every half-hour, looking for the repeated dips caused by planet crossings, or “transits.”
The more times a planet crosses its star, the more easily it is picked up and tagged by computers analyzing Kepler’s data. And Kepler’s first hits were indeed of planets that orbited their suns in a few days in close orbits that would produce oven-cleaner temperatures. The Earth, of course, takes a year to go around the Sun, so it would take two or three years for its analogue orbiting some star in Cygnus to show up in the Kepler data.
“We will find Earth-size planets in habitable zones,” Dr. Marcy stated flatly last month in Seattle.
Required: Absolute Proof
There is a hitch to confirming those planets, however. Such planets would not exert enough of a gravitational tug on their suns to be detectable by the “wobble” method, the main way their masses can be measured. Instead of confirming such planets, Kepler astronomers talk about “validating” them by using high-powered telescopes to make sure, for example, that there is only one star there and not a pair of eclipsing stars or some other phenomenon that could mimic a planet’s shadow.
“Earths are difficult,” Mr. Borucki said. “We’re concerned not to announce anything until we’ve proven six different ways it can’t not be a planet.”
As a result, more and more of Kepler’s future pronouncements will be statistical in nature. Natalie Batalha of San Jose State University, the deputy science team leader for Kepler, said it could be that they will wind up with, say, 100 planets they are 80 percent sure of, which could translate to 80 planets — useful for a census, not so helpful if you’re looking for a place to live.
“It’s a bitter pill to swallow,” said Sara Seager, an M.I.T. planetary astronomer who works with Kepler. “We will be faced with hundreds of planet candidates that may never be fully vetted as planets. We just have to live with statistics.”
But providing statistics, and not pinpointing individual planets, has always been Kepler’s prime mission. The road map to new worlds, Dr. Batalha explained, goes like this: First, Kepler figures out how abundant Earths are and how far you have to go out into the universe to find one. That information is needed to design the next step — a mission that would search the sky for Earth-like planets that are close enough to study. But at 500 to 3,000 light-years away, Kepler’s planets are too far for intense direct scrutiny.
“Once you know where they are, you study the heck out of them,” looking for spectral indications of an atmosphere and anything else, including biomarkers that are the signature of living things, Dr. Batalha wrote in an e-mail. “Everyone and their dog will be looking for biomarkers on these worlds.”
One idea for such a mission is a “starshade” that would float in front of a telescope in space and cancel out the bright light from a star, allowing its much dimmer planets to stand out.
Shading a New Telescope
Indeed, some astronomers have proposed building such a starshade for the James Webb Space Telescope, Hubble’s successor, which is scheduled to be launched by NASA later this decade. “It could potentially not only image an Earth-like planet, but provide some information about its atmosphere and surface,” said David Spergel, an astrophysicist from Princeton.
Mr. Borucki likes to compare the quest for other worlds to the building of the great cathedrals, a task handed from generation to generation of believers. And what if we finally find what we are looking for?
“The fact that we find lots of Earths just means that we have to spend a lot more money to build the next mission and go and find out if they speak English or French,” Mr. Borucki said.
If we are alone, on the other hand, “maybe we’re going to go conquer the whole galaxy,” he said. “Nobody’s out there to stop us.”
Monday, January 31, 2011
Saturday, December 18, 2010
Babylonia Ahead of Their Time
* Scribes in Old Babylonian period knew Pythagoras's theorem 1,000 years before he did
* Cuneiform tablets in New York exhibition show sophistication of Babylonian mathematicians
* Interest in this strand of history growing
(CNN) -- Over 1,000 years before Pythagoras was calculating the length of a hypotenuse, sophisticated scribes in Mesopotamia were working with the same theory to calculate the area of their farmland.
Working on clay tablets, students would "write" out their math problems in cuneiform script, a method that involved making wedge-shaped impressions in the clay with a blunt reed.
These tablets bear evidence of practical as well as more advanced theoretical math and show just how sophisticated the ancient Babylonians were with numbers -- more than a millennium before Pythagoras and Euclid were doing the same in ancient Greece.
"They are the most sophisticated mathematics from anywhere in the world at that time," said Alexander Jones, a Professor of the History of the Exact Sciences in Antiquity at New York University.
He is co-curator of "Before Pythagoras: The Culture of Old Babylonian Mathematics," an exhibition at the Institute for the Study of the Ancient World in New York.
They are the most sophisticated mathematics from anywhere in the world at that time
--Curator Alexander Jones
"This is nearly 4,000 years ago and there's no other ancient culture at that time that we know of that is doing anything like that level of work. It seems to be going beyond anything that daily life needs," he said.
Many scribes were trained in the ancient city of Nippur in what is now southern Iraq, where a large number of tablets were discovered between the mid-19th century and the 1920s.
Typical problems they worked on involved calculating the area of a given field, or the width of a trench.
These problems, says Jones, required the kind of math training taught to American Grade 10 students, but not in a format we would now recognize.
"It's not like algebra, it's all written out in words and numerals but no symbols and no times signs or equals or anything like that," he said.
This system, and the lack of recognizable Western mathematical symbols such as x and y, meant that it was several years before historians and archaeologists understood just what was represented on these tablets.
It took a young Austrian mathematician in the 1920s, named Otto Neugebauer, to crack the mathematical system and work out what the ancient Babylonians were calculating. But despite his advances, it is only recently that interest in Babylonian math has started to take hold.
"I think that before Neugebauer and even after Neugebauer, there wasn't a lot of attention placed on mathematical training in Babylon even though we have this rich cuneiform history with the tablets," said Jennifer Chi, Associate Director for Exhibitions and Public Programs at Institute for the Study of the Ancient World.
When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid. That shouldn't be the case.
One of the aims of the institute, she says, is to find interconnections between ancient cultures as well as look at what the institute sees as under-represented ancient cultures -- and the culture of ancient Babylonian math, she says, is ripe for popular revision.
"When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid," she said, but that "this shouldn't be the case."
And though ancient Babylonia is often referred to in popular culture as a "lost" world, in fact much more evidence of mathematical learning from the period exists than from ancient Greece, said Chi.
Jones of New York University believes that there is much more that could be excavated but that, of course, current conditions in Iraq are not favorable. Still, there are enough tablets in collections across the world for mathematical historians to get stuck into.
For non-mathematicians, these tablets are a fascinating document of life in Mesopotamia. Most of the problems displayed are grounded in the everyday needs of ancient Babylonians.
But some tablets show the students engaging in what Jones calls "recreational math" -- math for math's sake.
"The only point of learning to do this kind of thing is really as a mental exercise, as a way of showing how smart you are," he said.
And it seems there is still more to learn from the Babylonians. Duncan Melville is a Professor of Mathematics at St. Lawrence University in Canton, New York, whose special interest is Mesopotamian mathematics.
According to Melville, teachers can continue to learn a thing or two about the way math was taught in Mesopotamia.
"You look at the way they set up their sequences of problems and it's all very carefully graduated, from simple problems to more complicated problems," he said.
"As a teacher of mathematics, it's very interesting to see how they organized their material," he continued. "There's still interesting things to learn from cutting-edge pedagogy 4,000 years ago."
With research continuing into this strand of ancient history, it remains to be seen whether Pythagoras's theorem will come to bear the name of an old Babylonian scribe instead.
From CNN December 18, 2010
* Cuneiform tablets in New York exhibition show sophistication of Babylonian mathematicians
* Interest in this strand of history growing
(CNN) -- Over 1,000 years before Pythagoras was calculating the length of a hypotenuse, sophisticated scribes in Mesopotamia were working with the same theory to calculate the area of their farmland.
Working on clay tablets, students would "write" out their math problems in cuneiform script, a method that involved making wedge-shaped impressions in the clay with a blunt reed.
These tablets bear evidence of practical as well as more advanced theoretical math and show just how sophisticated the ancient Babylonians were with numbers -- more than a millennium before Pythagoras and Euclid were doing the same in ancient Greece.
"They are the most sophisticated mathematics from anywhere in the world at that time," said Alexander Jones, a Professor of the History of the Exact Sciences in Antiquity at New York University.
He is co-curator of "Before Pythagoras: The Culture of Old Babylonian Mathematics," an exhibition at the Institute for the Study of the Ancient World in New York.
They are the most sophisticated mathematics from anywhere in the world at that time
--Curator Alexander Jones
"This is nearly 4,000 years ago and there's no other ancient culture at that time that we know of that is doing anything like that level of work. It seems to be going beyond anything that daily life needs," he said.
Many scribes were trained in the ancient city of Nippur in what is now southern Iraq, where a large number of tablets were discovered between the mid-19th century and the 1920s.
Typical problems they worked on involved calculating the area of a given field, or the width of a trench.
These problems, says Jones, required the kind of math training taught to American Grade 10 students, but not in a format we would now recognize.
"It's not like algebra, it's all written out in words and numerals but no symbols and no times signs or equals or anything like that," he said.
This system, and the lack of recognizable Western mathematical symbols such as x and y, meant that it was several years before historians and archaeologists understood just what was represented on these tablets.
It took a young Austrian mathematician in the 1920s, named Otto Neugebauer, to crack the mathematical system and work out what the ancient Babylonians were calculating. But despite his advances, it is only recently that interest in Babylonian math has started to take hold.
"I think that before Neugebauer and even after Neugebauer, there wasn't a lot of attention placed on mathematical training in Babylon even though we have this rich cuneiform history with the tablets," said Jennifer Chi, Associate Director for Exhibitions and Public Programs at Institute for the Study of the Ancient World.
When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid. That shouldn't be the case.
One of the aims of the institute, she says, is to find interconnections between ancient cultures as well as look at what the institute sees as under-represented ancient cultures -- and the culture of ancient Babylonian math, she says, is ripe for popular revision.
"When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid," she said, but that "this shouldn't be the case."
And though ancient Babylonia is often referred to in popular culture as a "lost" world, in fact much more evidence of mathematical learning from the period exists than from ancient Greece, said Chi.
Jones of New York University believes that there is much more that could be excavated but that, of course, current conditions in Iraq are not favorable. Still, there are enough tablets in collections across the world for mathematical historians to get stuck into.
For non-mathematicians, these tablets are a fascinating document of life in Mesopotamia. Most of the problems displayed are grounded in the everyday needs of ancient Babylonians.
But some tablets show the students engaging in what Jones calls "recreational math" -- math for math's sake.
"The only point of learning to do this kind of thing is really as a mental exercise, as a way of showing how smart you are," he said.
And it seems there is still more to learn from the Babylonians. Duncan Melville is a Professor of Mathematics at St. Lawrence University in Canton, New York, whose special interest is Mesopotamian mathematics.
According to Melville, teachers can continue to learn a thing or two about the way math was taught in Mesopotamia.
"You look at the way they set up their sequences of problems and it's all very carefully graduated, from simple problems to more complicated problems," he said.
"As a teacher of mathematics, it's very interesting to see how they organized their material," he continued. "There's still interesting things to learn from cutting-edge pedagogy 4,000 years ago."
With research continuing into this strand of ancient history, it remains to be seen whether Pythagoras's theorem will come to bear the name of an old Babylonian scribe instead.
From CNN December 18, 2010
Thursday, December 16, 2010
Electromagnetic Energy Naval Rail Gun
(Dec. 14) -- The world's most powerful gun is one step closer to becoming the super-weapon of the future.
The Navy on Friday demonstrated a record-setting 33-megajoule shot from its developmental electromagnetic rail gun, a weapon that will be able to shoot farther than conventional guns. This weapon of the future could someday go on U.S. Navy ships, but for right now, it's a science and technology project.
Normally, a ship-based weapon would require gunpowder or a rocket boost to shoot projectiles, but the electromagnetic gun is powered by an electric pulse generated by the ship. Since the projectiles travel at speeds of more than seven times the speed of sound, they don't even require high explosives to pack a big punch: The kinetic energy of the projectile is more than enough to create a lethal effect.
Why does the Navy want it? Range and speed make the rail gun a particularly attractive weapon for the Navy, though other advantages include its accuracy and safety onboard a ship (because it doesn't require high explosives). "The 33-megajoule shot means the Navy can fire projectiles at least 110 nautical miles (126 miles), placing sailors and Marines at a safe standoff distance and out of harm's way, and the high velocities achievable are tactically relevant for air and missile defense," Rear Adm. Nevin Carr, chief of naval research, said in a release announcing the latest test.
How much does it cost? The Navy has budgeted about $250 million for the development of the prototype rail gun. It's impossible to say how much the final system would cost to buy. As with any new weapon system, the price tag is likely to be high, but advocates for the rail gun point out the projectiles would be cheaper than conventional missiles and ammunition.
When will the weapon be used on a ship? Not anytime soon. The Navy projects it won't be ready until sometime in the 2020 to 2025 time range, and that assumes the Navy pursues it beyond the prototype.
Filed under: Nation, Tech, AOL Original
The Navy on Friday demonstrated a record-setting 33-megajoule shot from its developmental electromagnetic rail gun, a weapon that will be able to shoot farther than conventional guns. This weapon of the future could someday go on U.S. Navy ships, but for right now, it's a science and technology project.
Normally, a ship-based weapon would require gunpowder or a rocket boost to shoot projectiles, but the electromagnetic gun is powered by an electric pulse generated by the ship. Since the projectiles travel at speeds of more than seven times the speed of sound, they don't even require high explosives to pack a big punch: The kinetic energy of the projectile is more than enough to create a lethal effect.
Why does the Navy want it? Range and speed make the rail gun a particularly attractive weapon for the Navy, though other advantages include its accuracy and safety onboard a ship (because it doesn't require high explosives). "The 33-megajoule shot means the Navy can fire projectiles at least 110 nautical miles (126 miles), placing sailors and Marines at a safe standoff distance and out of harm's way, and the high velocities achievable are tactically relevant for air and missile defense," Rear Adm. Nevin Carr, chief of naval research, said in a release announcing the latest test.
How much does it cost? The Navy has budgeted about $250 million for the development of the prototype rail gun. It's impossible to say how much the final system would cost to buy. As with any new weapon system, the price tag is likely to be high, but advocates for the rail gun point out the projectiles would be cheaper than conventional missiles and ammunition.
When will the weapon be used on a ship? Not anytime soon. The Navy projects it won't be ready until sometime in the 2020 to 2025 time range, and that assumes the Navy pursues it beyond the prototype.
Filed under: Nation, Tech, AOL Original
Sunday, December 5, 2010
New Life Form - Is God Dead?
AOL News Article, Dec. 5, 2010
Does a New Life Form Mean God Is Dead?
David Gibson
Religion Reporter
The discovery of what is apparently an entirely new form of life -- a bacteria based on toxic arsenic rather than phosphorus, one of the six building blocks of all life on Earth -- has set the scientific world abuzz, prompting White House inquiries to NASA and threatening to upend longstanding beliefs about biology.
But some say the announcement also signals an end to religious faith, or at least the beginning of the end, because it implies that life can spring forth unexpectedly on Earth or even on other planets, and in unexpected forms -- developments that seem to run counter to literal readings of biblical creation accounts.
"The polite thing to say is that discoveries such as this don't really impeach the credibility of established religion, but in truth of course they really do," David Niose, president of the American Humanist Association (AHA), a leading secularist organization, said of this week's revelations about the microbes discovered in Lake Mono in California.
"The fact that life can spring forth in this way from nature, taken in context with what else we've learned in recent centuries about space and time, surely makes it less plausible that the human animal is the specially favored creation of all-powerful, all-knowing divinity," Niose said.
Another shot in the Wars of Science and Religion? Maybe not.
The arsenic-based microbe discovery "sounds like a nice piece of work; we'll see where it goes from here," Brother Guy Consolmagno, a Jesuit and a planetary scientist at the Vatican Observatory, wrote in an e-mail to Politics Daily. (Yes, the Catholic Church was doing science long before Galileo.)
"But," he added, "any scientific discovery that broadens our knowledge of creation, deepens our understanding of the Creator."
Consolmagno, who a few weeks ago made news for saying he'd be delighted to find intelligent life on other planets, is typical of religious believers who don't see faith and science as natural enemies.
Even some vocal atheists who see belief and science as inevitable opponents -- with belief the problem, not the solution -- weren't buying the AHA's arguments about the discovery's importance.
"I regret to say that the American Humanists got the story wrong," PZ Myers, a biologist at the University of Minnesota and a famously trenchant critic of religion, told Politics Daily. Myers, who details his arguments at his blog, says the problem is their reading of the science.
"They say 'a new form of life has been discovered that apparently evolved outside the scope of all previously discovered life on Earth,' and this is not correct: the bacteria studied share a common ancestor with us, and the novelty of the discovery was not the organism, but that this entirely earthly organism was capable of incorporating arsenic into its chemistry. So no, their claims of its significant impact on our understanding of the history of life on Earth are overblown."
Myers does see a silver lining of sorts (at least from his non-believer's point of view) because the discovery "does represent an incremental increase in our understanding, just as science does every day."
"The point should be that the whole of science provides a direct challenge to religious belief, not that any one event is so definitive," Myers said.
Brother Guy would disagree with that assertion, but he pointed out that for the AHA and similar groups, "obviously this is no 'proof' since obviously they'd decided years ago, for whatever other reasons, that there was no God."
Faith, it seems, comes in many forms.
Niose of the American Humanist Association did concede that it is "unlikely that this discovery will change the minds of those who insist on a literal interpretation of the Bible."
"To them, the world is about 6,000 years old and evolution is a hoax, and no amount of scientific evidence will change that. For the rest of us, however, this discovery is indeed profound, and it adds to the mountains of evidence that already point to the humanistic lifestance as being our best hope."
Maybe the true test of the impact of the discovery will come in a few years time, when we can see whether there are more tourists visiting Lake Mono looking for the arsenic-eating bugs or more pilgrims checking out the full-scale replica of Noah's Ark that a well-known creationist group said this week it will build in northern Kentucky -- at a cost of $150 million, including taxpayer subsidies.
Given the success of the group's Creation Museum, which drew its millionth visitor last spring, it'd be wise not to bet against the Ark.
David Gibson »
Does a New Life Form Mean God Is Dead?
David Gibson
Religion Reporter
The discovery of what is apparently an entirely new form of life -- a bacteria based on toxic arsenic rather than phosphorus, one of the six building blocks of all life on Earth -- has set the scientific world abuzz, prompting White House inquiries to NASA and threatening to upend longstanding beliefs about biology.
But some say the announcement also signals an end to religious faith, or at least the beginning of the end, because it implies that life can spring forth unexpectedly on Earth or even on other planets, and in unexpected forms -- developments that seem to run counter to literal readings of biblical creation accounts.
"The polite thing to say is that discoveries such as this don't really impeach the credibility of established religion, but in truth of course they really do," David Niose, president of the American Humanist Association (AHA), a leading secularist organization, said of this week's revelations about the microbes discovered in Lake Mono in California.
"The fact that life can spring forth in this way from nature, taken in context with what else we've learned in recent centuries about space and time, surely makes it less plausible that the human animal is the specially favored creation of all-powerful, all-knowing divinity," Niose said.
Another shot in the Wars of Science and Religion? Maybe not.
The arsenic-based microbe discovery "sounds like a nice piece of work; we'll see where it goes from here," Brother Guy Consolmagno, a Jesuit and a planetary scientist at the Vatican Observatory, wrote in an e-mail to Politics Daily. (Yes, the Catholic Church was doing science long before Galileo.)
"But," he added, "any scientific discovery that broadens our knowledge of creation, deepens our understanding of the Creator."
Consolmagno, who a few weeks ago made news for saying he'd be delighted to find intelligent life on other planets, is typical of religious believers who don't see faith and science as natural enemies.
Even some vocal atheists who see belief and science as inevitable opponents -- with belief the problem, not the solution -- weren't buying the AHA's arguments about the discovery's importance.
"I regret to say that the American Humanists got the story wrong," PZ Myers, a biologist at the University of Minnesota and a famously trenchant critic of religion, told Politics Daily. Myers, who details his arguments at his blog, says the problem is their reading of the science.
"They say 'a new form of life has been discovered that apparently evolved outside the scope of all previously discovered life on Earth,' and this is not correct: the bacteria studied share a common ancestor with us, and the novelty of the discovery was not the organism, but that this entirely earthly organism was capable of incorporating arsenic into its chemistry. So no, their claims of its significant impact on our understanding of the history of life on Earth are overblown."
Myers does see a silver lining of sorts (at least from his non-believer's point of view) because the discovery "does represent an incremental increase in our understanding, just as science does every day."
"The point should be that the whole of science provides a direct challenge to religious belief, not that any one event is so definitive," Myers said.
Brother Guy would disagree with that assertion, but he pointed out that for the AHA and similar groups, "obviously this is no 'proof' since obviously they'd decided years ago, for whatever other reasons, that there was no God."
Faith, it seems, comes in many forms.
Niose of the American Humanist Association did concede that it is "unlikely that this discovery will change the minds of those who insist on a literal interpretation of the Bible."
"To them, the world is about 6,000 years old and evolution is a hoax, and no amount of scientific evidence will change that. For the rest of us, however, this discovery is indeed profound, and it adds to the mountains of evidence that already point to the humanistic lifestance as being our best hope."
Maybe the true test of the impact of the discovery will come in a few years time, when we can see whether there are more tourists visiting Lake Mono looking for the arsenic-eating bugs or more pilgrims checking out the full-scale replica of Noah's Ark that a well-known creationist group said this week it will build in northern Kentucky -- at a cost of $150 million, including taxpayer subsidies.
Given the success of the group's Creation Museum, which drew its millionth visitor last spring, it'd be wise not to bet against the Ark.
David Gibson »
Thursday, October 28, 2010
Scientists - Tens of Billions of Earth Size Planets in Milky Way
Scientists estimate tens of billions of Earth-size planets in Milky Way
Gallery
Searching for Earth-size planets outside our solar system
According to scientists, there are tens of billions of Earth-size planets in the galaxy.
By Marc Kaufman
Washington Post Staff Writer
Thursday, October 28, 2010; 2:02 PM
Nobody has seen them yet, but scientists now believe there are tens of billions of planets the general size and bulk of Earth in the Milky Way galaxy alone - a startling conclusion based on four years of viewing a small section of the nighttime sky.
Scientists estimate tens of billions of Earth-size planets in Milky Way
The estimate, made by astronomers Andrew Howard and Geoffrey Marcy of the University of California at Berkeley, flows from the simple logic that the number of small but detectable exoplanets - planets outside Earth's solar system - is substantially larger than the number of big exoplanets in distant solar systems.
In a paper released Thursday by the journal Science, the two report that based on this galactic preference for smaller planets, they can predict that almost one quarter of the stars similar to our sun will have Earth-size planets orbiting them.
"This is the first estimate based on actual measurements of the fraction of stars that have Earth-size planets," said Marcy, who did his observing with Howard at the Keck Observatory in Hawaii.
Their observations and extrapolations say nothing about whether all these Earth-size planets will actually have the characteristics of Earth: its density, its just-right distance from the sun, the fact that it is a rocky structure rather than gaseous ball.
But Marcy said that with so many Earth-size planets now expected to be orbiting distant suns - something on the order of 50,000,000,000,000,000,000,000 across the universe - the likelihood is high that many are in "habitable zones" where life can theoretically exist.
"It's tantalizing, without a doubt, to think some of those Earths are in habitable zones," Marcy said. "And based on what we know, really, why wouldn't they be?"
Current planet-hunting technology allows astronomers to find exoplanets down to the size of so-called super-Earths that are three times the size of our planet. The new conclusion that billions of planets similar in mass (or bulk) to Earth exist in the Milky Way is based on extrapolations of the number of these super-Earths compared with the number of larger exoplanets. Because the finding is not based on firm measurements, Marcy said "it's a very exciting set of numbers that we have confidence in, but there are yellow flags."
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Exoplanet hunters, who found the first planet outside our solar system in 1995, are entering a period of especially heightened and excited discovery. The new assessment from Howard and Marcy, funded by NASA and Keck Observatory, comes only weeks after two other astronomers published a paper saying they had detected an apparently rocky planet in a habitable zone around a star relatively close to Earth called Gliese 581G.
That conclusion by Steven Vogt of the University of California at Santa Cruz and Paul Butler of the Carnegie Institution in Washington, has not been confirmed, and some have challenged the discovery, especially a Swiss team that has been a leader in exoplanet research. But very few now doubt that Earth-size and Earth-like exoplanets in habitable zones will be found in the months and years ahead.
The assessment that Earth-size planets are ubiquitous in distant solar systems is expected to get additional support in February when the scientists operating NASA's Kepler Mission, which is searching for Earth-size and habitable planets, report on what they have been finding.
In a previous paper, the Kepler team reported finding about 350 new candidate planets that they are now in the process of confirming. Since the first exoplanet was identified 15 years ago, some 500 more both large and small have been discovered and confirmed.
Most were detected by measuring the minute wobbles of stars caused by the gravitational pull of the exoplanets that orbit them. This technique has been dramatically refined in recent years, and astronomers have been given the long telescope observation times needed to make the necessary measurements. The best planet hunters can now detect solar wobbles of as little as one meter per second.
The field has also been revolutionized by other increasingly sophisticated methods of detecting exoplanets, most especially using the "transit" method that looks for tiny reductions in the light coming from target stars - usually on the order of 100 parts per million. If these one-to-16-hour reductions are observed in a regular pattern over time, then astronomers know a planet is orbiting its sun.
Kepler mission is using similar "transiting" to search for Earth-size planets in one small section of the sky. Marcy, who is a member of the Kepler science team, said the orbiting telescope will survey thousands of stars to determine with unprecedented precision how many are circled by exoplanets, and especially by Earth-size exoplanets that might be in habitable zones. The size of the exoplanet can be determined by the amount the brightness of the star decreases when it transits its sun.
"This is an extraordinarily exciting time in exoplanets and distant Earths," Marcy said. "Think of it: We know that Aristotle was once at a cafe outside Athens drinking ouzo and speculating about whether there are other Earths in the universe. That's a question we're getting much closer to answering."
The 166 solar systems reported on Thursday by Howard and Marcy are all within 80 light-years of Earth - a short distance by astronomical measures. "What this means is that, as NASA develops new techniques over the next decade to find truly Earth-size planets, it won't have to look too far," Howard said.
Of 100 typical sun-like stars, his team determined, astronomers can expect to find two the size of Jupiter, six the size of Neptune and twelve "super-Earths" between three and ten times the size of our planet. This progression led to the conclusion that 100 sun-like stars would be orbited by 23 planets sized between one-half of an Earth and two Earths.
Gallery
Searching for Earth-size planets outside our solar system
According to scientists, there are tens of billions of Earth-size planets in the galaxy.
By Marc Kaufman
Washington Post Staff Writer
Thursday, October 28, 2010; 2:02 PM
Nobody has seen them yet, but scientists now believe there are tens of billions of planets the general size and bulk of Earth in the Milky Way galaxy alone - a startling conclusion based on four years of viewing a small section of the nighttime sky.
Scientists estimate tens of billions of Earth-size planets in Milky Way
The estimate, made by astronomers Andrew Howard and Geoffrey Marcy of the University of California at Berkeley, flows from the simple logic that the number of small but detectable exoplanets - planets outside Earth's solar system - is substantially larger than the number of big exoplanets in distant solar systems.
In a paper released Thursday by the journal Science, the two report that based on this galactic preference for smaller planets, they can predict that almost one quarter of the stars similar to our sun will have Earth-size planets orbiting them.
"This is the first estimate based on actual measurements of the fraction of stars that have Earth-size planets," said Marcy, who did his observing with Howard at the Keck Observatory in Hawaii.
Their observations and extrapolations say nothing about whether all these Earth-size planets will actually have the characteristics of Earth: its density, its just-right distance from the sun, the fact that it is a rocky structure rather than gaseous ball.
But Marcy said that with so many Earth-size planets now expected to be orbiting distant suns - something on the order of 50,000,000,000,000,000,000,000 across the universe - the likelihood is high that many are in "habitable zones" where life can theoretically exist.
"It's tantalizing, without a doubt, to think some of those Earths are in habitable zones," Marcy said. "And based on what we know, really, why wouldn't they be?"
Current planet-hunting technology allows astronomers to find exoplanets down to the size of so-called super-Earths that are three times the size of our planet. The new conclusion that billions of planets similar in mass (or bulk) to Earth exist in the Milky Way is based on extrapolations of the number of these super-Earths compared with the number of larger exoplanets. Because the finding is not based on firm measurements, Marcy said "it's a very exciting set of numbers that we have confidence in, but there are yellow flags."
ad_icon
Exoplanet hunters, who found the first planet outside our solar system in 1995, are entering a period of especially heightened and excited discovery. The new assessment from Howard and Marcy, funded by NASA and Keck Observatory, comes only weeks after two other astronomers published a paper saying they had detected an apparently rocky planet in a habitable zone around a star relatively close to Earth called Gliese 581G.
That conclusion by Steven Vogt of the University of California at Santa Cruz and Paul Butler of the Carnegie Institution in Washington, has not been confirmed, and some have challenged the discovery, especially a Swiss team that has been a leader in exoplanet research. But very few now doubt that Earth-size and Earth-like exoplanets in habitable zones will be found in the months and years ahead.
The assessment that Earth-size planets are ubiquitous in distant solar systems is expected to get additional support in February when the scientists operating NASA's Kepler Mission, which is searching for Earth-size and habitable planets, report on what they have been finding.
In a previous paper, the Kepler team reported finding about 350 new candidate planets that they are now in the process of confirming. Since the first exoplanet was identified 15 years ago, some 500 more both large and small have been discovered and confirmed.
Most were detected by measuring the minute wobbles of stars caused by the gravitational pull of the exoplanets that orbit them. This technique has been dramatically refined in recent years, and astronomers have been given the long telescope observation times needed to make the necessary measurements. The best planet hunters can now detect solar wobbles of as little as one meter per second.
The field has also been revolutionized by other increasingly sophisticated methods of detecting exoplanets, most especially using the "transit" method that looks for tiny reductions in the light coming from target stars - usually on the order of 100 parts per million. If these one-to-16-hour reductions are observed in a regular pattern over time, then astronomers know a planet is orbiting its sun.
Kepler mission is using similar "transiting" to search for Earth-size planets in one small section of the sky. Marcy, who is a member of the Kepler science team, said the orbiting telescope will survey thousands of stars to determine with unprecedented precision how many are circled by exoplanets, and especially by Earth-size exoplanets that might be in habitable zones. The size of the exoplanet can be determined by the amount the brightness of the star decreases when it transits its sun.
"This is an extraordinarily exciting time in exoplanets and distant Earths," Marcy said. "Think of it: We know that Aristotle was once at a cafe outside Athens drinking ouzo and speculating about whether there are other Earths in the universe. That's a question we're getting much closer to answering."
The 166 solar systems reported on Thursday by Howard and Marcy are all within 80 light-years of Earth - a short distance by astronomical measures. "What this means is that, as NASA develops new techniques over the next decade to find truly Earth-size planets, it won't have to look too far," Howard said.
Of 100 typical sun-like stars, his team determined, astronomers can expect to find two the size of Jupiter, six the size of Neptune and twelve "super-Earths" between three and ten times the size of our planet. This progression led to the conclusion that 100 sun-like stars would be orbited by 23 planets sized between one-half of an Earth and two Earths.
Thursday, September 30, 2010
Stem Cells From Skin - Same As Embryonic
Scientists overcome hurdles to stem cell alternatives
By Rob Stein
Washington Post Staff Writer
Thursday, September 30, 2010; 8:43 PM
Scientists have invented an efficient way to produce apparently safe alternatives to human embryonic stem cells without destroying embryos, a long-sought step toward bypassing the moral morass surrounding one of the most promising fields in medicine.
A team of researchers at the Harvard Stem Cell Institute in Boston published a series of experiments Thursday showing that synthetic biological signals can quickly reprogram ordinary skin cells into entities that appear virtually identical to embryonic stem cells. Moreover, the same strategy can then turn those cells into ones that could be used for transplants.
"This is going to be very exciting to the research community," said Derrick J. Rossi of the Children's Hospital Boston, who led the research published in the journal Cell Stem Cell. "We now have an experimental paradigm for generating patient-specific cells highly efficiently and safely and also taking those cells to clinically useful cell types."
Scientists hope stem cells will lead to cures for diabetes, Alzheimer's disease, spinal cord injuries, heart attacks and many other ailments because they can turn into almost any tissue in the body, potentially providing an invaluable source of cells to replace those damaged by disease or injury. But the cells can only be obtained by destroying days-old embryos.
The cells produced by the Harvard team, known as induced pluripotent stem cells or iPS cells, would avoid that ethical objection and could in some ways be superior to embryonic stem cells. For example, iPS cells could enable scientists to take an easily obtainable skin cell from any patient and use it to create perfectly matched cells, tissue and potentially even entire organs for transplants that would be immune to rejection.
'Game changer'
While cautioning that the work needed to be repeated elsewhere and explored further, other researchers said the technique appeared to represent a major development in the promising field of "regenerative medicine," which aims to create treatments tailored to individual patients.
"All I can say is 'wow' - this is a game changer," said Robert Lanza, a stem cell researcher at Advanced Cell Technology in Worcester, Mass. "It would solve some of the most important problems in the field." The results were so striking that the Harvard Stem Cell Institute where Rossi works had already ordered every scientist working on iPS cells to switch to the new process.
"This paper is a major paper, in my view, in the field of regenerative medicine," said Douglas A. Melton, a leading stem cell researcher who co-directs the institute.
The announcement comes as the future of federal funding for embryonic stem cell research hangs in doubt. A federal judge stunned the field Aug. 23 by ruling that the Obama administration's more permissive policy for funding the research violated a federal law barring taxpayer dollars from being used for studies that involve destroying human embryos. An appeals court Tuesday let the funding continue until the case is resolved.
Opponents of human embryonic stem cell research seized on the development as the most convincing evidence yet that the morally questionable cells were unnecessary.
"With each new study it becomes more and more implausible to claim that scientists must rely on destruction of human embryos to achieve rapid progress in regenerative medicine," said Richard M. Doerflinger of the U.S. Conference of Catholic Bishops.
Rossi and other researchers, however, said that embryonic stem cells were still crucial because, among other things, they remained irreplaceable for evaluating alternatives.
"The new report provides a substantial advance," said National Institutes of Health Director Francis S. Collins. "But this research in no way reduces the importance of comparing the resulting iPS cells to human embryonic stem cells. Previous research has shown that iPS cells retain some memory of their tissue of origin, which may have important implications for their use in therapeutics. To explore these important potential differences, iPS research must continue to be conducted side by side with human embryonic cell research."
In 2006, researchers discovered that they could coax adult cells into a state that appeared identical to embryonic stem cells and then, just like embryonic stem cells, morph these iPS cells into various tissue. But the process involved inserting genes into cells using retroviruses, which raised the risk the cells could cause cancer. Since then, scientists have been trying to develop safer methods. Several approaches using chemicals or other types of viruses have shown promise. But none has eliminated the safety concerns, and most have been slow and balky.
Cell conversion
The new approach involves molecules known as "messenger RNA" (mRNA), which cells use to create proteins they need carry out vital functions. Working in the laboratory, the researchers created mRNA molecules carrying the instructions for the cell's machinery to produce the four key proteins needed to reprogram into iPS cells.
After tinkering with the mRNA molecules to make signals that the cells would not destroy as dangerous invaders, the researchers found that a daily cocktail of their creations was remarkably fast and efficient at reprogramming the cells. The technique converted the cells in about half the time of previous methods--only about 17 days--with surprising economy--up to 100 times more efficient that the standard approach. "We ended up with so many colonies of cells all over the place that we had to stop the experiment," Rossi said.
Moreover, the cells had not experienced any disturbing changes in their DNA caused by previous methods and appeared much more indistinguishable from embryonic stem cells than iPS cells created using other methods. In addition, the researchers went one step further and showed that they could use the strategy to quickly and easily convert the iPS cells they created into a specific cell types - in this case muscle cells.
"If you put all these things together, several of the major hurdles towards clinical translation of iPS cells are addressed by this technology," Rossi said. "That's what we've very excited about." Others agreed. Lanza, for example, called the approach "almost too good to be true," saying it evoked the magical alchemy of "turning lead into gold." "The ability to safely and efficiently generate patient-specific cells has the potential to transform transplantation medicine," Lanza said.
In an e-mail, stem cell pioneer Shinya Yamanaka of Kyoto University in Japan, who helped discover iPS cells, said he planned to immediately try the technique in his lab. "The standard method to generate [iPS cells] for clinical applications has yet to be established," Yamanaka wrote. "I think this method has the potential for it."
Rossi said the approach should also be useful far beyond stem cells by offering a way to treat any genetic condition in which a protein is missing, deficient or defective.
"It has amazing potential in the therapeutic realm," Rossi said.
By Rob Stein
Washington Post Staff Writer
Thursday, September 30, 2010; 8:43 PM
Scientists have invented an efficient way to produce apparently safe alternatives to human embryonic stem cells without destroying embryos, a long-sought step toward bypassing the moral morass surrounding one of the most promising fields in medicine.
A team of researchers at the Harvard Stem Cell Institute in Boston published a series of experiments Thursday showing that synthetic biological signals can quickly reprogram ordinary skin cells into entities that appear virtually identical to embryonic stem cells. Moreover, the same strategy can then turn those cells into ones that could be used for transplants.
"This is going to be very exciting to the research community," said Derrick J. Rossi of the Children's Hospital Boston, who led the research published in the journal Cell Stem Cell. "We now have an experimental paradigm for generating patient-specific cells highly efficiently and safely and also taking those cells to clinically useful cell types."
Scientists hope stem cells will lead to cures for diabetes, Alzheimer's disease, spinal cord injuries, heart attacks and many other ailments because they can turn into almost any tissue in the body, potentially providing an invaluable source of cells to replace those damaged by disease or injury. But the cells can only be obtained by destroying days-old embryos.
The cells produced by the Harvard team, known as induced pluripotent stem cells or iPS cells, would avoid that ethical objection and could in some ways be superior to embryonic stem cells. For example, iPS cells could enable scientists to take an easily obtainable skin cell from any patient and use it to create perfectly matched cells, tissue and potentially even entire organs for transplants that would be immune to rejection.
'Game changer'
While cautioning that the work needed to be repeated elsewhere and explored further, other researchers said the technique appeared to represent a major development in the promising field of "regenerative medicine," which aims to create treatments tailored to individual patients.
"All I can say is 'wow' - this is a game changer," said Robert Lanza, a stem cell researcher at Advanced Cell Technology in Worcester, Mass. "It would solve some of the most important problems in the field." The results were so striking that the Harvard Stem Cell Institute where Rossi works had already ordered every scientist working on iPS cells to switch to the new process.
"This paper is a major paper, in my view, in the field of regenerative medicine," said Douglas A. Melton, a leading stem cell researcher who co-directs the institute.
The announcement comes as the future of federal funding for embryonic stem cell research hangs in doubt. A federal judge stunned the field Aug. 23 by ruling that the Obama administration's more permissive policy for funding the research violated a federal law barring taxpayer dollars from being used for studies that involve destroying human embryos. An appeals court Tuesday let the funding continue until the case is resolved.
Opponents of human embryonic stem cell research seized on the development as the most convincing evidence yet that the morally questionable cells were unnecessary.
"With each new study it becomes more and more implausible to claim that scientists must rely on destruction of human embryos to achieve rapid progress in regenerative medicine," said Richard M. Doerflinger of the U.S. Conference of Catholic Bishops.
Rossi and other researchers, however, said that embryonic stem cells were still crucial because, among other things, they remained irreplaceable for evaluating alternatives.
"The new report provides a substantial advance," said National Institutes of Health Director Francis S. Collins. "But this research in no way reduces the importance of comparing the resulting iPS cells to human embryonic stem cells. Previous research has shown that iPS cells retain some memory of their tissue of origin, which may have important implications for their use in therapeutics. To explore these important potential differences, iPS research must continue to be conducted side by side with human embryonic cell research."
In 2006, researchers discovered that they could coax adult cells into a state that appeared identical to embryonic stem cells and then, just like embryonic stem cells, morph these iPS cells into various tissue. But the process involved inserting genes into cells using retroviruses, which raised the risk the cells could cause cancer. Since then, scientists have been trying to develop safer methods. Several approaches using chemicals or other types of viruses have shown promise. But none has eliminated the safety concerns, and most have been slow and balky.
Cell conversion
The new approach involves molecules known as "messenger RNA" (mRNA), which cells use to create proteins they need carry out vital functions. Working in the laboratory, the researchers created mRNA molecules carrying the instructions for the cell's machinery to produce the four key proteins needed to reprogram into iPS cells.
After tinkering with the mRNA molecules to make signals that the cells would not destroy as dangerous invaders, the researchers found that a daily cocktail of their creations was remarkably fast and efficient at reprogramming the cells. The technique converted the cells in about half the time of previous methods--only about 17 days--with surprising economy--up to 100 times more efficient that the standard approach. "We ended up with so many colonies of cells all over the place that we had to stop the experiment," Rossi said.
Moreover, the cells had not experienced any disturbing changes in their DNA caused by previous methods and appeared much more indistinguishable from embryonic stem cells than iPS cells created using other methods. In addition, the researchers went one step further and showed that they could use the strategy to quickly and easily convert the iPS cells they created into a specific cell types - in this case muscle cells.
"If you put all these things together, several of the major hurdles towards clinical translation of iPS cells are addressed by this technology," Rossi said. "That's what we've very excited about." Others agreed. Lanza, for example, called the approach "almost too good to be true," saying it evoked the magical alchemy of "turning lead into gold." "The ability to safely and efficiently generate patient-specific cells has the potential to transform transplantation medicine," Lanza said.
In an e-mail, stem cell pioneer Shinya Yamanaka of Kyoto University in Japan, who helped discover iPS cells, said he planned to immediately try the technique in his lab. "The standard method to generate [iPS cells] for clinical applications has yet to be established," Yamanaka wrote. "I think this method has the potential for it."
Rossi said the approach should also be useful far beyond stem cells by offering a way to treat any genetic condition in which a protein is missing, deficient or defective.
"It has amazing potential in the therapeutic realm," Rossi said.
Wednesday, September 29, 2010
Found: A Planet Like Earth
Time Magazine - September 29, 2010
Michael D. Lemonick
The star known as Gliese 581 is utterly unremarkable in just about every way you can imagine. It's a red dwarf, the most common type of star in the Milky Way, weighing in at about a third the mass of the Sun. At 20 light years or so away, it's relatively nearby, but not close enough to set any records (it's the 117th closest star to Earth, for what that's worth). You can't even see it without a telescope, so while it lies in direction of Libra, it isn't one of the shining dots you'd connect to form the constellation. It's no wonder that the star's name lacks even a whiff of mystery or romance.
But Gliese 581 does have one distinction — and that's enough to make it the focus of intense scientific attention. At last count, astronomers had identified more than 400 planets orbiting stars beyond the Sun, and Gliese 581 was host to no fewer than four of them — the most populous solar system we know of, aside than our own. That alone would make the star intriguing. But on Wednesday, a team of astronomers announced they'd found two more planets circling the star, bringing the total to six. And one of them, assigned the name Gliese 581g, may be of truly historic significance. (See an illustrated history of Planet Earth.)
For one thing, the planet is only about three or four times as massive as our home world, meaning it probably has a solid surface just like Earth. Much more important, it sits smack in the middle of the so-called habitable zone, orbiting at just the right distance from the star to let water remain liquid rather than freezing solid or boiling away. As far as we know, that's a minimum requirement for the presence of life. For thousands of years, philosophers and scientists have wondered whether other Earths existed out in the cosmos. And since the first, very un-Eearthlike extrasolar planet was discovered in 1995, astronomers have been inching closer to answering that question. Now, they've evidently succeeded (although to be clear, there's no way at this point to determine whether there actually is life on the new planet).
"We're pretty excited about it," admits Steve Vogt, of the University of California, Santa Cruz, a member of the team, in a masterpiece of understatement. "I think this is what everyone's been after for the past 15 years." (See the top 50 space moments since Sputnik.)
Planetary scientist James Kasting, of Penn State University, who wasn't involved with the discovery, agrees. "I think they've scooped the Kepler people," he says. Kasting refers to the Kepler space telescope, launched into space early last year on a mission to determine how common Earthlike planets might be. The "Kepler people" have a number of candidate Earths in the can, but are still working to confirm them. (See pictures of Earth from space.)
Being first isn't the main reason Vogt is excited, however. "Someone had to be first," he says. "But this is right next door to us. That's the big result." What's particularly big about it is a matter of simple arithmetic. With only 116 stars closer to Earth than this one, it was hardly a sure thing that so small a sample group would produce two habitable planets, including Earth. And two such planets may be an undercount, Vogt says, since just nine out of those 100-plus stars have been studied in any detail. Indeed, one of Gliese 581g's sister planets, known as Gliese 581d (OK, they truly don't put a lot of creative energy into naming these things) could conceivably be a habitable world itself.
One of the four planets known to orbit Gliese 581 before the latest discovery, 581d was found by a team of Swiss astronomers in 2007 and was thought to be outside the habitable zone, and thus too cold for liquid water. But a reanalysis last year brought it into the zone, albeit just barely. The problem is, Gliese 581d is also too big to be Earthlike; it's probably made mostly of nonwater ice, like Neptune and Uranus, which makes a poorer candidate for life than 581g.
Lost in the excitement over possible life on the new world is what a remarkable achievement its mere discovery was. Detecting a planet this small is monstrously hard—and would have been impossible when Vogt and co-discoverer Paul Butler, of the Carnegie Institution of Washington first got into the planet-hunting game in the early 1990s. The instruments you use to detect tiny back-and-forth motions in the star — motions caused by the orbiting planet's gravitational tugs, which are often the only way to infer that the worlds exist at all—simply weren't sensitive enough. Since then, though, says Vogt, "I've been busting my gut to improve the instruments, and Paul has been busting his got to do the observations." In all, those observations span more than 200 nights on the giant Keck I telescope in Hawaii over 11 years, supplemented by observations from the Geneva group — and that painstaking work finally confirmed 581g's existence.
None of this proves that there actually is water on Gliese 581g. "Those are things we just have to speculate about," says Vogt. But he goes on to point out that there's water pretty much everywhere else you look. "There's water on Earth," he says, "and on the Moon, and Mars, and on Jupiter's moon Europa and Saturn's moon Enceladus, and in interstellar space. There's enough water produced in the Orion Nebula every 24 seconds to fill the Earth's oceans."
It's not hard to imagine, in other words, that Gliese 581g might have plenty of water as well. "It could have quite a good ocean," Vogt says. Certainly, it could still be a sterile, non-biological ocean. But unlike any planet found until now, there's nothing to rule out the idea that could also be teeming with life.
Read more: http://www.time.com/time/health/article/0,8599,2022489,00.html?hpt=T2#ixzz10y6BNV3G
Michael D. Lemonick
The star known as Gliese 581 is utterly unremarkable in just about every way you can imagine. It's a red dwarf, the most common type of star in the Milky Way, weighing in at about a third the mass of the Sun. At 20 light years or so away, it's relatively nearby, but not close enough to set any records (it's the 117th closest star to Earth, for what that's worth). You can't even see it without a telescope, so while it lies in direction of Libra, it isn't one of the shining dots you'd connect to form the constellation. It's no wonder that the star's name lacks even a whiff of mystery or romance.
But Gliese 581 does have one distinction — and that's enough to make it the focus of intense scientific attention. At last count, astronomers had identified more than 400 planets orbiting stars beyond the Sun, and Gliese 581 was host to no fewer than four of them — the most populous solar system we know of, aside than our own. That alone would make the star intriguing. But on Wednesday, a team of astronomers announced they'd found two more planets circling the star, bringing the total to six. And one of them, assigned the name Gliese 581g, may be of truly historic significance. (See an illustrated history of Planet Earth.)
For one thing, the planet is only about three or four times as massive as our home world, meaning it probably has a solid surface just like Earth. Much more important, it sits smack in the middle of the so-called habitable zone, orbiting at just the right distance from the star to let water remain liquid rather than freezing solid or boiling away. As far as we know, that's a minimum requirement for the presence of life. For thousands of years, philosophers and scientists have wondered whether other Earths existed out in the cosmos. And since the first, very un-Eearthlike extrasolar planet was discovered in 1995, astronomers have been inching closer to answering that question. Now, they've evidently succeeded (although to be clear, there's no way at this point to determine whether there actually is life on the new planet).
"We're pretty excited about it," admits Steve Vogt, of the University of California, Santa Cruz, a member of the team, in a masterpiece of understatement. "I think this is what everyone's been after for the past 15 years." (See the top 50 space moments since Sputnik.)
Planetary scientist James Kasting, of Penn State University, who wasn't involved with the discovery, agrees. "I think they've scooped the Kepler people," he says. Kasting refers to the Kepler space telescope, launched into space early last year on a mission to determine how common Earthlike planets might be. The "Kepler people" have a number of candidate Earths in the can, but are still working to confirm them. (See pictures of Earth from space.)
Being first isn't the main reason Vogt is excited, however. "Someone had to be first," he says. "But this is right next door to us. That's the big result." What's particularly big about it is a matter of simple arithmetic. With only 116 stars closer to Earth than this one, it was hardly a sure thing that so small a sample group would produce two habitable planets, including Earth. And two such planets may be an undercount, Vogt says, since just nine out of those 100-plus stars have been studied in any detail. Indeed, one of Gliese 581g's sister planets, known as Gliese 581d (OK, they truly don't put a lot of creative energy into naming these things) could conceivably be a habitable world itself.
One of the four planets known to orbit Gliese 581 before the latest discovery, 581d was found by a team of Swiss astronomers in 2007 and was thought to be outside the habitable zone, and thus too cold for liquid water. But a reanalysis last year brought it into the zone, albeit just barely. The problem is, Gliese 581d is also too big to be Earthlike; it's probably made mostly of nonwater ice, like Neptune and Uranus, which makes a poorer candidate for life than 581g.
Lost in the excitement over possible life on the new world is what a remarkable achievement its mere discovery was. Detecting a planet this small is monstrously hard—and would have been impossible when Vogt and co-discoverer Paul Butler, of the Carnegie Institution of Washington first got into the planet-hunting game in the early 1990s. The instruments you use to detect tiny back-and-forth motions in the star — motions caused by the orbiting planet's gravitational tugs, which are often the only way to infer that the worlds exist at all—simply weren't sensitive enough. Since then, though, says Vogt, "I've been busting my gut to improve the instruments, and Paul has been busting his got to do the observations." In all, those observations span more than 200 nights on the giant Keck I telescope in Hawaii over 11 years, supplemented by observations from the Geneva group — and that painstaking work finally confirmed 581g's existence.
None of this proves that there actually is water on Gliese 581g. "Those are things we just have to speculate about," says Vogt. But he goes on to point out that there's water pretty much everywhere else you look. "There's water on Earth," he says, "and on the Moon, and Mars, and on Jupiter's moon Europa and Saturn's moon Enceladus, and in interstellar space. There's enough water produced in the Orion Nebula every 24 seconds to fill the Earth's oceans."
It's not hard to imagine, in other words, that Gliese 581g might have plenty of water as well. "It could have quite a good ocean," Vogt says. Certainly, it could still be a sterile, non-biological ocean. But unlike any planet found until now, there's nothing to rule out the idea that could also be teeming with life.
Read more: http://www.time.com/time/health/article/0,8599,2022489,00.html?hpt=T2#ixzz10y6BNV3G
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