Using NASA's Spitzer Space Telescope, astronomers have confirmed the discovery of the nearest rocky planet outside our solar system, larger than Earth and a potential gold mine of science data.
Dubbed HD 219134b, this exoplanet, which orbits too close to its star to sustain life, is a mere 21 light-years away. While the planet itself can't be seen directly, even by telescopes, the star it orbits is visible to the naked eye in dark skies in the Cassiopeia constellation, near the North Star.
HD 219134b is also the closest exoplanet to Earth to be detected transiting, or crossing in front of, its star and, therefore, perfect for extensive research.
"Transiting exoplanets are worth their weight in gold because they can be extensively characterized," said Michael Werner, the project scientist for the Spitzer mission at NASA's Jet Propulsion Laboratory in Pasadena, California. "This exoplanet will be one of the most studied for decades to come."
The planet, initially discovered using the HARPS-North instrument on the Italian 3.6-meter Galileo National Telescope in the Canary Islands, is the subject of a study accepted for publication in the journal Astronomy & Astrophysics.
Study lead author Ati Motalebi of the Geneva Observatory in Switzerland said she believes the planet is the ideal target for NASA's James Webb Space Telescope in 2018.
"Webb and future large, ground-based observatories are sure to point at it and examine it in detail," Motalebi said.
Only a small fraction of exoplanets can be detected transiting their stars due to their relative orientation to Earth. When the orientation is just right, the planet's orbit places it between its star and Earth, dimming the detectable light of its star. It's this dimming of the star that is actually captured by observatories such as Spitzer and can reveal not only the size of the planet but also clues about its composition.
"Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor," said astronomer and study co-author Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. For reference, the closest known planet is GJ674b at 14.8 light-years away; its composition is unknown.
HD 219134b was first sighted by the HARPS-North instrument and a method called the radial velocity technique, in which a planet's mass and orbit can be measured by the tug it exerts on its host star. The planet was determined to have a mass 4.5 times that of Earth, and a speedy three-day orbit around its star.
Spitzer followed up on the finding, discovering the planet transits its star. Infrared measurements from Spitzer revealed the planet's size, about 1.6 times that of Earth. Combining the size and mass gives it a density of 3.5 ounces per cubic inch (six grams per cubic centimeter) -- confirming HD 219134b is a rocky planet.
Now that astronomers know HD 219134b transits its star, scientists will be scrambling to observe it from the ground and space. The goal is to tease chemical information out of the dimming starlight as the planet passes before it. If the planet has an atmosphere, chemicals in it can imprint patterns in the observed starlight.
Rocky planets such as this one, with bigger-than-Earth proportions, belong to a growing class of planets termed super-Earths.
"Thanks to NASA's Kepler mission, we know super-Earths are ubiquitous in our galaxy, but we still know very little about them," said co-author Michael Gillon of the University of Liege in Belgium, lead scientist for the Spitzer detection of the transit. "Now we have a local specimen to study in greater detail. It can be considered a kind of Rosetta Stone for the study of super-Earths."
Further observations with HARPS-North also revealed three more planets in the same star system, farther than HD 219134b. Two are relatively small and not too far from the star. Small, tightly packed multi-planet systems are completely different from our own solar system, but, like super-Earths, are being found in increasing numbers.
Friday, 7 August 2015
Thursday, 6 August 2015
Hubble Video
Wednesday, 5 August 2015
Philae poses comet chemistry conundrum (Chemistry World 30th July)
Nevertheless, Jen Blank, a senior scientist at the Nasa Ames Research Center in California, US, highlights the historic achievement of syncing orbit with a comet and sending a lander down to the surface. ‘The Philae data are amazing,’ enthuses Blank, who’s studied how comets may have supplied Earth with molecules needed for life, but wasn’t involved in Rosetta or Philae. ‘These are the first measurements of organic compounds collected directly on a comet or asteroid.’
Philae was programmed to take sniffs shortly after touching down on 67P as an ‘insurance policy’, explains Ian Wright from the Open University in Milton Keynes, UK, and principal investigator for Ptolemy. That was well planned, because the touchdown became a rebound that sent Philae out of communication range, preventing further measurements to date.
The lander was also therefore in motion in the minutes between the instruments doing their respective basic analyses, or sniffs, of whatever material happened to have entered them. One potential explanation for the distinct results is therefore that they reflect differences between locations on the comet, Wright suggests. The fact that COSAC’s sample port is on Philae’s underside, and Ptolemy’s is on its top is another. ‘Have we analysed separate grains?’ Wright asks. ‘We’ve no reason to expect that the surface would be homogenous.’
Exhausting serendipity
COSAC’s best sniff happened automatically 25 minutes after Philae’s first contact, while the lander was around 150 metres above the surface. The instrument consists of a gas chromatograph and a time-of-flight mass spectrometer intended to analyse organic compounds in samples drilled from the comet’s surface. Though Philae couldn’t drill, the impact threw up some solid material, part of which apparently entered COSAC’s two exhaust pipes. The COSAC team, headed by Fred Goesmann from the Max Planck Institute for Solar System Research in Göttingen, Germany, thinks the exhaust’s warmth evaporated volatile compounds, allowing their detection.
However, the small amount of material COSAC was looking at meant it couldn’t detect anything but the smallest compounds. That means it wouldn’t have seen any ‘molecules of life’, such as amino acids, even if they were present. And although it could have, it didn’t see much ammonia, formaldehyde or carbon dioxide, which are common components of cometary ice, or any sulfur compounds. The COSAC scientists link the lack of ice to measurements previously made by Rosetta showing 67P’s surface is covered in a carbon-based coat rather than frozen.
Icy isolation
To determine isotope ratios of chemicals on 67P and establish their origins, Ptolemy’s gas chromatograph and ion trap mass spectrometer were also supposed to be fed drilled samples. However, it was reduced to making six sniffs at 14 second intervals about 20 minutes after Philae hit 67P. Like COSAC, it failed to find any signs of sulfur. Ptolemy saw mostly water and carbon dioxide, ice components expected on comets, but no significant indication of ammonia, and very low levels of nitrogen compounds overall. The COSAC scientists suggest that the absence of this key source of nitrogen could be because it has evaporated or been used up in reactions.John Plane from the atmospheric and planetary chemistry group at the University of Leeds calls these measurements ‘technically incredible’. ‘It’s a wonderful achievement to get any data,’ he says. Plane is especially pleased because COSAC’s findings support lab experiments showing cometary ice can produce small organic molecules. ‘It’s nice to have them confirmed, and get a first idea of relative abundance,’ he says. ‘That’s useful if you want to simulate the next step, how these molecules could react together to make peptides and DNA.’
Meanwhile, Rosetta has recently regained tenuous contact with Philae, enough for scientific commands to be sent to Ptolemy last week, Wright reveals. ‘We haven’t got any data back,’ he admits. ‘When we get a communication window it might come back, but it’s a fingers crossed job. As time goes on we’re becoming less convinced that’s going to happen.’
Tuesday, 4 August 2015
Could Our Universe Have Features of A Giamt Black Hole? (Journal of Cosmology, June 2015)
Interesting article from Journal of Cosmology; using black hole data along with Schwarzschild's equation and average density equat, the size and mass of our visible universe plots on a logarithimic scale.
Abstract;
The 2013 Planck Survey results yielded the following estimates for mass (1.46 x 1053kg), radius (4.3 x 1026 m) and average density (4.08 x 10-28 kg/m3) for the visible portion of our universe. These mass and density numbers are for the baryonic (“ordinary”) matter portion only. These data can be plotted in close proximity (within approximately a factor of 2) to the projection lines of a logarithmic graph of calculated black hole mass vs. Schwarzschild radius and black hole average density vs. Schwarzschild radius, respectively. The Schwarzschild formula, rs = 2GM/c2, and a simple black hole average density formula, Ro = 3c2/8piGrs 2, are used to calculate mass and average density for theoretical black holes ranging from microscopic to the radius of our visible universe, and these values are plotted on the logarithmic graph.
The possible implications of these findings are discussed, including a rationale for the possibility that the largest black holes (giant “dark black holes”) may be beyond our capability to detect them. It remains to be seen whether adding in dark matter massand average density contributions to the graph would put our universe exactly on the black hole projection lines, or within the shaded territory exclusive to black holes, but the possibility of this happening is not ruled out at the present time.
http://journalofcosmology.com/JOC25/COULD%20OUR%20UNIVERSE%20HAVE%20FEATURES%20OF%20A%20GIANT%20BLACK%20HOLE%20in%20Word%20copy%202-1
Abstract;
The 2013 Planck Survey results yielded the following estimates for mass (1.46 x 1053kg), radius (4.3 x 1026 m) and average density (4.08 x 10-28 kg/m3) for the visible portion of our universe. These mass and density numbers are for the baryonic (“ordinary”) matter portion only. These data can be plotted in close proximity (within approximately a factor of 2) to the projection lines of a logarithmic graph of calculated black hole mass vs. Schwarzschild radius and black hole average density vs. Schwarzschild radius, respectively. The Schwarzschild formula, rs = 2GM/c2, and a simple black hole average density formula, Ro = 3c2/8piGrs 2, are used to calculate mass and average density for theoretical black holes ranging from microscopic to the radius of our visible universe, and these values are plotted on the logarithmic graph.
The possible implications of these findings are discussed, including a rationale for the possibility that the largest black holes (giant “dark black holes”) may be beyond our capability to detect them. It remains to be seen whether adding in dark matter massand average density contributions to the graph would put our universe exactly on the black hole projection lines, or within the shaded territory exclusive to black holes, but the possibility of this happening is not ruled out at the present time.
http://journalofcosmology.com/JOC25/COULD%20OUR%20UNIVERSE%20HAVE%20FEATURES%20OF%20A%20GIANT%20BLACK%20HOLE%20in%20Word%20copy%202-1
Monday, 3 August 2015
A galactic vampire - The Milky Way is not as young as it looks (The Economist, 21st Feb)
AS EVERY horror fan knows, the secret of eternal youth is to suck the lifeblood of others. If you are a galaxy, that lifeblood is hydrogen gas, from which stars form. And it seems that some galaxies are indeed able to maintain a youthful appearance by sucking great clouds of the stuff in from intergalactic space.
According to Felix Lockman of America’s National Radio Astronomy Observatory, the Milky Way, humanity’s home galaxy, is one such vampire. Dr Lockman is part of a team that has been using the Green Bank radio telescope in West Virginia, which boasts the world’s largest steerable dish, to study the process.
In the 1960s a strange intergalactic gas cloud was discovered near the Milky Way by an astronomer called Gail Smith. Smith’s cloud, as it is known, is an elongated structure almost 10,000 light-years from end to end. At roughly a tenth of the diameter of the Milky Way’s disc, that is big even by galactic standards. Smith’s cloud was a puzzle. No other such object had ever been seen. It was therefore put aside by astronomers, for it is hard to do useful science when you have only one example of something. Dr Lockman and his colleagues have now rectified that neglect. Their measurements show the cloud is on a collision course with the Milky Way. It will hit one of the arms of the spiral in about 30m years, and then be absorbed into the galaxy, probably triggering a burst of star formation in the process.
This suggested to the team that they had found the mechanism of eternal galactic youth: galaxies eat gas clouds. If that were true it would imply that such clouds must be quite common.
And that is what theory predicts. Recent calculations about how matter is distributed in the universe suggest that a good number of such clouds should, indeed, be out there. These calculations concern not the hydrogen itself, but the real fabric of the universe: a still-mysterious substance known as dark matter that interacts with the familiar, atomic, sort only through the force of gravity. The calculations suggest that there should be dark-matter globs of the right mass to attract interstellar gas clouds as big as Smith’s. And when Dr Lockman used Green Bank to search for such clouds, he found ten in just one small volume of nearby space.
The mystery of the ever-youthful Milky Way thus seems to be solved. Spiral galaxies are constantly rejuvenated by collisions with things like Smith’s cloud. Eventually, the supply of these clouds will run out, and with it the elixir of galactic life. But that will not be for many billions of years. Meanwhile, the universe’s spiral galaxies will keep on keeping young.
According to Felix Lockman of America’s National Radio Astronomy Observatory, the Milky Way, humanity’s home galaxy, is one such vampire. Dr Lockman is part of a team that has been using the Green Bank radio telescope in West Virginia, which boasts the world’s largest steerable dish, to study the process.
This suggested to the team that they had found the mechanism of eternal galactic youth: galaxies eat gas clouds. If that were true it would imply that such clouds must be quite common.
And that is what theory predicts. Recent calculations about how matter is distributed in the universe suggest that a good number of such clouds should, indeed, be out there. These calculations concern not the hydrogen itself, but the real fabric of the universe: a still-mysterious substance known as dark matter that interacts with the familiar, atomic, sort only through the force of gravity. The calculations suggest that there should be dark-matter globs of the right mass to attract interstellar gas clouds as big as Smith’s. And when Dr Lockman used Green Bank to search for such clouds, he found ten in just one small volume of nearby space.
The mystery of the ever-youthful Milky Way thus seems to be solved. Spiral galaxies are constantly rejuvenated by collisions with things like Smith’s cloud. Eventually, the supply of these clouds will run out, and with it the elixir of galactic life. But that will not be for many billions of years. Meanwhile, the universe’s spiral galaxies will keep on keeping young.
Researchers call for interstellar messages to alien civilizations (sciencemag.org)
SAN JOSE, CALIFORNIA—Is it time to send deliberate messages to the stars, in the hopes of reaching alien civilizations? Advocates in the Search for Extraterrestrial Intelligence (SETI) say that moment is long overdue. But other researchers want to take a more cautious approach and seek an international consensus before outing Earth to the rest of the universe. Scientists in both camps faced off today at a debate held at a meeting of AAAS (which publishes Science) here.
Douglas Vakoch, the director of interstellar message composition at the SETI Institute in Mountain View, California, doesn’t dismiss the need to consider ethical or political issues, but says that it will be tough to achieve a consensus. “It’s ‘either-or’ thinking,” he says. “Either we have international discussion, or we transmit. We should be doing both.” But David Brin, an astrophysicist and science fiction author here, says that Earth’s relative radio quietude should not be changed so radically, so quickly. “If you’re going to transform one of the major characteristics … of our planet, we’ve learned that small groups shouldn’t do that peremptorily.
Since the SETI movement began in the 1960s, it has mostly involved using radio telescopes to listen to bands in the electromagnetic spectrum for something out of the ordinary. In contrast, instances of active SETI, also called Messaging Extraterrestrial Intelligence, or METI—beaming deliberate messages to the heavens—have been much rarer. In 1974, a radio message was broadcast from the Arecibo telescope in Puerto Rico toward a cluster of stars 25,000 light-years away. Brin says there have been other “stunts.” In 2008, for instance, the tortilla chip company Doritos sent an advertisement from a radar station in Norway to a potentially habitable star system 42 light-years away.
Advocates for active SETI say that keen-eared aliens could already pick up some of Earth’s ambient transmissions. Current radio and TV transmissions could be heard only a few light-years away with the current radio telescope technology on Earth, but Vakoch says that an advanced civilization would have far more developed techniques for listening. Brin says this is the “barn door excuse” and adds that many active SETI techniques would send out focused, powerful messages that would travel many times farther than the day-to-day transmissions from Earth. He views active SETI messages as cosmic pollution, rather than exploration. Although he’s not worried about alien invasions, he thinks the assumption of benevolence—or even the existence of aliens—is overstated.
Vakoch says the SETI Institute has no imminent plans to start transmitting messages, but he finds that other organizations are not taking the lead in holding international discussions on the issue. He says that one efficient way of transmitting messages would be by adding messages in the regular course of doing planetary science. When the Arecibo radar is used to study asteroids, for instance, messages could be sent to stars near the line of sight of the asteroid without much additional effort. What would these messages include? Seth Shostak, an astronomer at the SETI Institute, wants to beam the entire Internet. Vakoch would prefer something humble that conveys the challenges that humanity faces.
Brin doesn’t see resolution to the passionate debate anytime soon. “It’s an area where opinion rules, and everyone has a fierce opinion.”
Douglas Vakoch, the director of interstellar message composition at the SETI Institute in Mountain View, California, doesn’t dismiss the need to consider ethical or political issues, but says that it will be tough to achieve a consensus. “It’s ‘either-or’ thinking,” he says. “Either we have international discussion, or we transmit. We should be doing both.” But David Brin, an astrophysicist and science fiction author here, says that Earth’s relative radio quietude should not be changed so radically, so quickly. “If you’re going to transform one of the major characteristics … of our planet, we’ve learned that small groups shouldn’t do that peremptorily.
Since the SETI movement began in the 1960s, it has mostly involved using radio telescopes to listen to bands in the electromagnetic spectrum for something out of the ordinary. In contrast, instances of active SETI, also called Messaging Extraterrestrial Intelligence, or METI—beaming deliberate messages to the heavens—have been much rarer. In 1974, a radio message was broadcast from the Arecibo telescope in Puerto Rico toward a cluster of stars 25,000 light-years away. Brin says there have been other “stunts.” In 2008, for instance, the tortilla chip company Doritos sent an advertisement from a radar station in Norway to a potentially habitable star system 42 light-years away.
Advocates for active SETI say that keen-eared aliens could already pick up some of Earth’s ambient transmissions. Current radio and TV transmissions could be heard only a few light-years away with the current radio telescope technology on Earth, but Vakoch says that an advanced civilization would have far more developed techniques for listening. Brin says this is the “barn door excuse” and adds that many active SETI techniques would send out focused, powerful messages that would travel many times farther than the day-to-day transmissions from Earth. He views active SETI messages as cosmic pollution, rather than exploration. Although he’s not worried about alien invasions, he thinks the assumption of benevolence—or even the existence of aliens—is overstated.
Vakoch says the SETI Institute has no imminent plans to start transmitting messages, but he finds that other organizations are not taking the lead in holding international discussions on the issue. He says that one efficient way of transmitting messages would be by adding messages in the regular course of doing planetary science. When the Arecibo radar is used to study asteroids, for instance, messages could be sent to stars near the line of sight of the asteroid without much additional effort. What would these messages include? Seth Shostak, an astronomer at the SETI Institute, wants to beam the entire Internet. Vakoch would prefer something humble that conveys the challenges that humanity faces.
Brin doesn’t see resolution to the passionate debate anytime soon. “It’s an area where opinion rules, and everyone has a fierce opinion.”
SETI Debates the Wisdom of Revealing Ourselves to the Galaxy (AAAS Feb 2015)
Should we shout.....or should we keep quiet...?
SAN JOSE, California — They don't hold out much hope that Vulcans will arrive on our doorsteps intoning "live long and prosper," but many astronomers believe that making radio contact with an alien civilization would fundamentally alter humanity for the better. For fifty years, however, they have searched the sky for signs of intelligent beings elsewhere in the universe with no result. Some think it's time to start sending our own messages to the stars in hope that someone up there will reply.
So-called "active SETI" is controversial. Astrophysicist Steven Hawking famously cautioned against shouting out our presence into the void, saying that first contact "… didn't turn out very well for the Native Americans." In response to such concerns, the nonprofit SETI Institute held one of the first public debates on the wisdom of active SETI, at the AAAS annual meeting.
The chances of someone picking up the message are better than ever. Recent data "encourages those who are optimistic about life in the universe," said astrobiologist David Grinspoon of the Planetary Science Institute at a 12 February news conference. Scientists now believe one in five sun-like stars have planets with conditions suitable for life, he reported. And research on extreme organisms on Earth, which eke out existence in the most challenging of environments, suggests that life could survive in even more unlikely places. The more common life in general is, Grinspoon suggested, the more probable that some of it has evolved intelligence and perhaps the ability to communicate.
SETI astronomer Douglas Vakoch argued that the time has come to stop waiting for some other galactic civilization to establish contact with us and make the first gesture ourselves. After all, if no one is transmitting messages, we don't have much chance of hearing one. "Sometimes we talk about SETI as an attempt to join the galactic club," Vakoch said, "but no one ever talks about paying our dues or even submitting an application."
The first step, Vakoch said, is to send out a signal that an extraterrestrial version of the SETI project could pick up. The message, he suggested, could be sent in the spare time of the Arecibo telescope in Puerto Rico, which astronomer Frank Drake used to send a coded message to a distant star cluster in 1974.
Speaking out against blabbing our presence to the stars was David Brin of Futures Unlimited in San Diego. Perhaps we haven't heard from alien civilizations because we're listening in the wrong place or with the wrong technology, he said. Perhaps they are waiting for us to make the first move. Or, maybe there's a more sinister explanation. Given the lack of any solid data, he said, SETI scientists' assumption that any galactic civilization capable of communicating with us would be benign is a dangerous one.
Brin called for a self-imposed halt on active broadcasts until there can be a global discussion of the potential risks and benefits. He compared this to the pause biologists placed on genetic engineering in the early 1990s to discuss the technology's risks and best practices. This moratorium, Brin said, ultimately resulted in better and safer research. In particular, he called for the inclusion of historians who could caution astronomers about the potential dangers of making contact. Here on Earth, Brin said, no first contact between peoples has ever been painless, even when there have been the best of intentions.
Today's debate is just one step in an ongoing exploration of actively pinging the galaxy. The SETI Institute plans to hold a day-long workshop Saturday at its Mountain View campus. The meeting is slated to include the perspectives of historians and religious scholars, according to SETI Institute CEO David Black, who organized the meeting. The objective, Black said, is to start figuring out how to regulate and plan any active SETI efforts. Currently, he said, there's no law preventing people from renting time on a radio telescope and "firing off a signal." The potential impact of announcing ourselves to the galaxy is immense, he said, and he expects a long debate. If we decide to pick up the phone, the next question is what we want to say.
SAN JOSE, California — They don't hold out much hope that Vulcans will arrive on our doorsteps intoning "live long and prosper," but many astronomers believe that making radio contact with an alien civilization would fundamentally alter humanity for the better. For fifty years, however, they have searched the sky for signs of intelligent beings elsewhere in the universe with no result. Some think it's time to start sending our own messages to the stars in hope that someone up there will reply.
So-called "active SETI" is controversial. Astrophysicist Steven Hawking famously cautioned against shouting out our presence into the void, saying that first contact "… didn't turn out very well for the Native Americans." In response to such concerns, the nonprofit SETI Institute held one of the first public debates on the wisdom of active SETI, at the AAAS annual meeting.
The chances of someone picking up the message are better than ever. Recent data "encourages those who are optimistic about life in the universe," said astrobiologist David Grinspoon of the Planetary Science Institute at a 12 February news conference. Scientists now believe one in five sun-like stars have planets with conditions suitable for life, he reported. And research on extreme organisms on Earth, which eke out existence in the most challenging of environments, suggests that life could survive in even more unlikely places. The more common life in general is, Grinspoon suggested, the more probable that some of it has evolved intelligence and perhaps the ability to communicate.
SETI astronomer Douglas Vakoch argued that the time has come to stop waiting for some other galactic civilization to establish contact with us and make the first gesture ourselves. After all, if no one is transmitting messages, we don't have much chance of hearing one. "Sometimes we talk about SETI as an attempt to join the galactic club," Vakoch said, "but no one ever talks about paying our dues or even submitting an application."
The first step, Vakoch said, is to send out a signal that an extraterrestrial version of the SETI project could pick up. The message, he suggested, could be sent in the spare time of the Arecibo telescope in Puerto Rico, which astronomer Frank Drake used to send a coded message to a distant star cluster in 1974.
Speaking out against blabbing our presence to the stars was David Brin of Futures Unlimited in San Diego. Perhaps we haven't heard from alien civilizations because we're listening in the wrong place or with the wrong technology, he said. Perhaps they are waiting for us to make the first move. Or, maybe there's a more sinister explanation. Given the lack of any solid data, he said, SETI scientists' assumption that any galactic civilization capable of communicating with us would be benign is a dangerous one.
Brin called for a self-imposed halt on active broadcasts until there can be a global discussion of the potential risks and benefits. He compared this to the pause biologists placed on genetic engineering in the early 1990s to discuss the technology's risks and best practices. This moratorium, Brin said, ultimately resulted in better and safer research. In particular, he called for the inclusion of historians who could caution astronomers about the potential dangers of making contact. Here on Earth, Brin said, no first contact between peoples has ever been painless, even when there have been the best of intentions.
"'I Love Lucy' is washing over the shores of a new planet out there on average once a day."
Seth Shostack
The possible benefits of making contact far outweigh the risks, said Seth Shostak, a senior astronomer at SETI. He argued that any alien civilization that could reach us to do us harm would be more than capable of detecting us already. Any extra terrestrial with technology just a few centuries beyond ours, he estimated, could find us based on the radio and television broadcasts we have inadvertently beamed into space since the mid-20th Century. "Our leakage is 70 light years into space," he said. "'I Love Lucy' is washing over the shores of a new planet out there on average once a day."
Brin called Shostak's claims assertions based on assumptions rather than data. "We are learning so much so fast," Brin said. "Fifteen years ago we knew of no planets outside our solar system — now it's thousands." Wouldn't make more sense, he asked, to pause and learn more before doing something that could change the fate of the world forever? Perhaps the risks of shouting into the interstellar jungle are small, but they are real, he said. "What we are saying is 'Let's talk about it.'"The possible benefits of making contact far outweigh the risks, said Seth Shostak, a senior astronomer at SETI. He argued that any alien civilization that could reach us to do us harm would be more than capable of detecting us already. Any extra terrestrial with technology just a few centuries beyond ours, he estimated, could find us based on the radio and television broadcasts we have inadvertently beamed into space since the mid-20th Century. "Our leakage is 70 light years into space," he said. "'I Love Lucy' is washing over the shores of a new planet out there on average once a day."
Today's debate is just one step in an ongoing exploration of actively pinging the galaxy. The SETI Institute plans to hold a day-long workshop Saturday at its Mountain View campus. The meeting is slated to include the perspectives of historians and religious scholars, according to SETI Institute CEO David Black, who organized the meeting. The objective, Black said, is to start figuring out how to regulate and plan any active SETI efforts. Currently, he said, there's no law preventing people from renting time on a radio telescope and "firing off a signal." The potential impact of announcing ourselves to the galaxy is immense, he said, and he expects a long debate. If we decide to pick up the phone, the next question is what we want to say.
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