Nov 12, 2020 08:27 PM
(This post was last modified: Nov 12, 2020 08:28 PM by C C.)
https://astronomy.com/news/2020/11/why-h...osed-minds
EXCERPTS: Limits don’t sit well with Avi Loeb. [...] When it comes to imagination, Loeb — cited in The New York Times “for his creative and prolific attempts to understand the … universe” — appears to have no shortage. ... Loeb is fearless because some of his out-there ideas have been publicly rebuked by other astronomers, says Penn State astronomer Jason Wright. But Loeb is rarely deterred by disapproving remarks, saying skepticism “can be a self-fulfilling prophecy.” It’s far better to look, he says, than to assume there’s nothing to be seen...
[...] Far from the city lights. Loeb and Princeton University astronomer Edwin Turner are kindred spirits who enjoy batting around speculative ideas. “The conservative impulse that serves science well in some ways doesn’t serve us well when it comes to generating hypotheses,” says Turner. While touring Abu Dhabi a decade ago, and learning that Dubai is so bright it can be seen from outer space, Loeb and Turner started to wonder whether our telescopes could pick up light from an alien city...
[...] Pollution as the solution to dilution ... the James Webb Space Telescope, which is scheduled for launch in 2021, will soon probe atmospheres of even more distant planets, looking for biological signatures of life. In 2014, Loeb and two collaborators, Henry Lin and Gonzalo Gonzalez Abad, decided to flip the switch: Instead of looking for signs of life, they suggested looking for signs of death, or at least serious contamination...
[...] The edge effect. A 2005 paper in the journal Astrobiology by MIT astronomer Sara Seager and three other researchers identified a distinct feature of an Earthlike planet covered with large stretches of vegetation. Plants appear green because they reflect light in the green part of the spectrum, but at higher wavelengths, between the red and infrared range, reflectance shoots up dramatically. ... In 2017, Lingam and Loeb got to wondering: What if an exoplanet was covered by vast tracts of photovoltaic arrays instead of boundless greenery? Massive structures like this, Lingam and Loeb reasoned, would produce an artificial spectral edge analogous to the red edge caused by vegetation, though occurring at different wavelengths...
[...] The mystery of FRBs. The first fast radio burst (FRB), an intense blast of radio waves emanating from outside our galaxy and lasting just a few milliseconds, was spotted in 2007. ... Lingam and Loeb offered a provocative solution to the puzzle: Maybe some of the FRBs are artificial...
Searching for artifacts. “When exploring habitable worlds around other stars, we might … find planets with burnt-up surfaces, abandoned mega-structures or planetary atmospheres rich with poisonous gases and no sign of life,” Loeb has written. One might also see an extensive network of unnatural platforms or satellites orbiting another star — perhaps part of a hypothetical energy-gathering enclosure called a Dyson sphere. Something like this, if sufficiently large, could be spotted by NASA’s Transiting Exoplanet Survey Satellite...
Searching for interstellar visitors. On Oct. 19, 2017, an astronomer using Hawaii’s Pan-STARRS telescope discovered an object moving past the sun at 196,000 miles per hour (315,431 km/hr), so fast that it almost surely originated from outside the solar system. The object, dubbed ‘Oumuamua — Hawaiian for “first scout from a distant place” — was initially classified as an asteroid and then a comet and more recently as a chunk of hydrogen ice. But Loeb has analyzed all of these ideas and finds that they still leave some questions unanswered...
[...] When it comes to SETI, evidence ultimately carries the day, Loeb insists. “We should collect evidence without prejudice, without assuming we know the truth in advance, and see what we learn.” On the other hand, he says, we should be open-minded and allow for some risk-taking in our pursuit of that evidence... (MORE - details)
EXCERPTS: Limits don’t sit well with Avi Loeb. [...] When it comes to imagination, Loeb — cited in The New York Times “for his creative and prolific attempts to understand the … universe” — appears to have no shortage. ... Loeb is fearless because some of his out-there ideas have been publicly rebuked by other astronomers, says Penn State astronomer Jason Wright. But Loeb is rarely deterred by disapproving remarks, saying skepticism “can be a self-fulfilling prophecy.” It’s far better to look, he says, than to assume there’s nothing to be seen...
[...] Far from the city lights. Loeb and Princeton University astronomer Edwin Turner are kindred spirits who enjoy batting around speculative ideas. “The conservative impulse that serves science well in some ways doesn’t serve us well when it comes to generating hypotheses,” says Turner. While touring Abu Dhabi a decade ago, and learning that Dubai is so bright it can be seen from outer space, Loeb and Turner started to wonder whether our telescopes could pick up light from an alien city...
[...] Pollution as the solution to dilution ... the James Webb Space Telescope, which is scheduled for launch in 2021, will soon probe atmospheres of even more distant planets, looking for biological signatures of life. In 2014, Loeb and two collaborators, Henry Lin and Gonzalo Gonzalez Abad, decided to flip the switch: Instead of looking for signs of life, they suggested looking for signs of death, or at least serious contamination...
[...] The edge effect. A 2005 paper in the journal Astrobiology by MIT astronomer Sara Seager and three other researchers identified a distinct feature of an Earthlike planet covered with large stretches of vegetation. Plants appear green because they reflect light in the green part of the spectrum, but at higher wavelengths, between the red and infrared range, reflectance shoots up dramatically. ... In 2017, Lingam and Loeb got to wondering: What if an exoplanet was covered by vast tracts of photovoltaic arrays instead of boundless greenery? Massive structures like this, Lingam and Loeb reasoned, would produce an artificial spectral edge analogous to the red edge caused by vegetation, though occurring at different wavelengths...
[...] The mystery of FRBs. The first fast radio burst (FRB), an intense blast of radio waves emanating from outside our galaxy and lasting just a few milliseconds, was spotted in 2007. ... Lingam and Loeb offered a provocative solution to the puzzle: Maybe some of the FRBs are artificial...
Searching for artifacts. “When exploring habitable worlds around other stars, we might … find planets with burnt-up surfaces, abandoned mega-structures or planetary atmospheres rich with poisonous gases and no sign of life,” Loeb has written. One might also see an extensive network of unnatural platforms or satellites orbiting another star — perhaps part of a hypothetical energy-gathering enclosure called a Dyson sphere. Something like this, if sufficiently large, could be spotted by NASA’s Transiting Exoplanet Survey Satellite...
Searching for interstellar visitors. On Oct. 19, 2017, an astronomer using Hawaii’s Pan-STARRS telescope discovered an object moving past the sun at 196,000 miles per hour (315,431 km/hr), so fast that it almost surely originated from outside the solar system. The object, dubbed ‘Oumuamua — Hawaiian for “first scout from a distant place” — was initially classified as an asteroid and then a comet and more recently as a chunk of hydrogen ice. But Loeb has analyzed all of these ideas and finds that they still leave some questions unanswered...
[...] When it comes to SETI, evidence ultimately carries the day, Loeb insists. “We should collect evidence without prejudice, without assuming we know the truth in advance, and see what we learn.” On the other hand, he says, we should be open-minded and allow for some risk-taking in our pursuit of that evidence... (MORE - details)
