Post by pim on May 28, 2017 23:22:23 GMT 10
What's "abiogenesis"? It's the word science uses to denote the development of life from non-life without any divine First Cause. If you're an atheist then you've no choice but to embrace the abiogenesis model. But adherence to religious faith doesn't necessarily rule out abiogenesis. I'm not interested in the God of the Starter Button or the God of the Ignition Key. Doesn't mean I reject religious faith outright. But we've had these round and round the merry go round so-called "debates" and all they do is feed the trolls. Besides, I'm posting this because whether the universe has a purpose or whether it's meaningless, absurd and purposeless in its vastness, it's still awesome. Not "awesome" in the way the kids use the word, but awesome in its dictionary meaning. It inspires awe.
Nobody knows if this planet of ours is the only one with a biosphere. There's no evidence, zip zero nada, of life having evolved on any other heavenly body. Won't stop us from looking of course and who knows maybe one day we'll find ET. Now at this point I could imagine posts saying "Oh ET is out there. Only a matter of time ..." and that might even be correct. We know the arguments and they're all based on probability theory because there is nothing else. Now don't misunderstand me, I'm not trying to say that there's no ET. How the hell would I know? How the hell would anyone know? But here's the thing: if at some stage it becomes possible to demonstrate beyond a reasonable doubt that abiogenesis only happened on this third planet of a minor star in the outer reaches of an ordinary galaxy and that none of the trillions of stars and planets in the billions of other galaxies contain a biosphere, then that would be mind boggling. Not just scientific in its implications but cultural, philosophical, cosmic and, dare I say it (my bloody oath I dare say it), spiritual.
Read this article. It's too lengthy and detailed to c & p in its entirety so I'll just put up the first bits. I hope though that you follow through and read all of it ...
The search for a habitable second Earth
We’ve never had a better chance of finding extraterrestrial life -- if it exists.
Steve Dent, www.engadget.com/amp/2017/05/27/search-habitable-planets-second-earth-exoplanets/
Contact with extraterrestrial life would be an epochal event. Even the discovery of a simple alien organism would be transformative, giving us unprecedented insight into how life forms on Earth and other planets. Yet, there's exactly zero proof that life exists beyond this world -- not one alien germ, spore or cell, let alone an advanced race that could save or enslave us. And we don't even know how life sprung up here 4 billion years ago from rocks, mud and water.
Scientists are torn on whether extraterrestrial life is abundant, rare or nonexistent. With 300 billion stars in the Milky Way, the late astronomer and futurist Carl Sagan figured there could be up to 10,000 advanced civilizations in our galaxy alone. Others, however, think not only are habitable planets rarer than thought, the odds of life forming are slight even on a promising world. In other words, we might be completely alone in our galaxy or even the universe.
Despite pessimism among some researchers, NASA has often implied that if a planet has the same conditions as Earth, it will automatically have life. "I see that as a marketing thing by NASA to interest people in planetary searches," said astronomer Caleb Scharf, who co-authored a paper on the odds of life forming on a planet. "I think [the chances] could be a lot lower, personally."
That's reinforced by another stark reality. "We haven't seen life everywhere we've looked so far," said astrobiologist Lauri Barge. "If life really requires some unique conditions to emerge, obviously Earth had them, but how many other planets would have them?"
So alien life might be out there, but there's a very good chance that it's not. Researchers are excited about either outcome and believe we're about to enter a golden age of planetary discovery. "Whether or not I'm optimistic that any life is out there, I am very optimistic that we're going to find out [either way]," NASA exoplanet researcher Shawn Domagal-Goldman told Engadget. "And I don't think we've ever had a moment like this in the history of our species."
Our prospects of finding alien life will explode in the next decade. NASA is on a tear hunting "exoplanets" -- planets orbiting stars outside our solar system -- with the satellites Spitzer, Hubble and particularly Kepler, launched in 2009. So far, the latter has discovered 2,335 exoplanets, 21 of which are in their star's habitable regions, and just the right size and mass for life. The most famous of those is Trappist-1, a seven-planet system discovered in February. It's just 40 light-years from Earth, and as many as three of its planets are in the "Goldilocks zone."
The Trappist-1 exoplanets will be one of the first targets of the $8.7 billion James Webb space telescope (JWST), set to launch in 2018. That instrument, parked a million miles from Earth, will be able to analyze the spectrum of exoplanet atmospheres to search for "biomarkers," or signs of life.
"If I was talking to you before [Trappist-1], I'd have said don't count on looking at the atmospheres of exoplanets, because you need darn-near-perfect targets," Domagal-Goldman said. "The Trappist planets are darn-near-perfect targets."
What exactly are we looking for?
Biologists don't even know how life sprang up on Earth, let alone elsewhere. It could have come via a process called abiogenesis, where life evolves via an electrochemical process from inert organic chemicals. Or it could have formed with "panspermia," in which simple life forms are ripped from one planet by a giant collision, survive a freezing ride through space and eventually collide into another planet, where they thrive anew. ("That's just outsourcing the problem," noted Scharf.)
We can't see exoplanets with a telescope -- they're too small, too far away and too overwhelmed by the light of their stars. If they pass in front of a star, however, Kepler can detect the star's dimming using the "transit method." Based on how much and how often the light dips, along with any wobble in the star, astronomers can figure out the planet's approximate size, mass and distance from its sun. Using stellar radiation models (that give the energy different stars emit) they can even estimate its surface temperature.
That's enough to figure out whether a planet is habitable. An ideal candidate has a temperature that supports liquid water and is less than twice the mass of Earth. That way, it's likely to have a rocky surface and gravity that won't crush nascent life.
Once a candidate is spotted, NASA will try to analyze its atmosphere. As it happens, Trappist-1 is an ideal study for the JWST because its relatively dim red dwarf star doesn't flood the planets around with light like larger stars do.
JWST's main instruments for sussing out Trappist-1 atmospheres will be its NIRCAM and NIRISS near-infrared cameras. When planets pass in front of the star, light will filter through their atmospheres and the instruments will pick out signature wavelengths of distinct chemicals. The cameras will particularly seek "biomarker" chemicals like ozone and methane (though that won't be easy), which usually exist only in the presence of organic life. Ozone, for one, is formed when oxygen produced by plants or phytoplankton is hit by ultraviolet light.
Either the presence or lack of an atmosphere on Trappist-1 will be of keen interest to scientists. "I want to know why those planets are uninhabitable," said Domagal-Goldman. "Is it because their atmospheres were stripped? Is it because they had some runaway greenhouse process that they never recovered from?"
The JWST won't be the only NASA instrument hunting life. The Transiting Exoplanet Survey Satellite (TESS) will also launch in 2018, searching for exoplanets around nearby stars. Like Kepler, it'll spot them using the transit method. Unlike Kepler, though, it'll scan very bright stars relatively close to Earth. Since those are up to 100 times more luminous than the ones observed by Kepler, it'll make follow-up observations by the JWST or Earth-based telescopes much easier, NASA said.
In the mid-2020s, NASA will launch WFIRST, a space telescope with a field of view 100 times wider than Hubble. That instrument will also do spectroscopic scans of exoplanets, but with much more detail than the JWST. Not only is it more powerful, it can better block out the glare of stars, giving it a clearer view of the exoplanets.
Along with those instruments, NASA is hunting exoplanets using the ground-based Large Binocular Telescope Interferometer, Spitzer Space Telescope and, yes, the Hubble Space Telescope. Its basic strategy is to find habitable exoplanet candidates using the transit method, then scan their atmospheres using spectroscopes via the erstwhile Hubble (recently repurposed for the task), JWST, WFIRST and large ground telescopes.
..... There's more, much more ...
Nobody knows if this planet of ours is the only one with a biosphere. There's no evidence, zip zero nada, of life having evolved on any other heavenly body. Won't stop us from looking of course and who knows maybe one day we'll find ET. Now at this point I could imagine posts saying "Oh ET is out there. Only a matter of time ..." and that might even be correct. We know the arguments and they're all based on probability theory because there is nothing else. Now don't misunderstand me, I'm not trying to say that there's no ET. How the hell would I know? How the hell would anyone know? But here's the thing: if at some stage it becomes possible to demonstrate beyond a reasonable doubt that abiogenesis only happened on this third planet of a minor star in the outer reaches of an ordinary galaxy and that none of the trillions of stars and planets in the billions of other galaxies contain a biosphere, then that would be mind boggling. Not just scientific in its implications but cultural, philosophical, cosmic and, dare I say it (my bloody oath I dare say it), spiritual.
Read this article. It's too lengthy and detailed to c & p in its entirety so I'll just put up the first bits. I hope though that you follow through and read all of it ...
The search for a habitable second Earth
We’ve never had a better chance of finding extraterrestrial life -- if it exists.
Steve Dent, www.engadget.com/amp/2017/05/27/search-habitable-planets-second-earth-exoplanets/
Contact with extraterrestrial life would be an epochal event. Even the discovery of a simple alien organism would be transformative, giving us unprecedented insight into how life forms on Earth and other planets. Yet, there's exactly zero proof that life exists beyond this world -- not one alien germ, spore or cell, let alone an advanced race that could save or enslave us. And we don't even know how life sprung up here 4 billion years ago from rocks, mud and water.
Scientists are torn on whether extraterrestrial life is abundant, rare or nonexistent. With 300 billion stars in the Milky Way, the late astronomer and futurist Carl Sagan figured there could be up to 10,000 advanced civilizations in our galaxy alone. Others, however, think not only are habitable planets rarer than thought, the odds of life forming are slight even on a promising world. In other words, we might be completely alone in our galaxy or even the universe.
Despite pessimism among some researchers, NASA has often implied that if a planet has the same conditions as Earth, it will automatically have life. "I see that as a marketing thing by NASA to interest people in planetary searches," said astronomer Caleb Scharf, who co-authored a paper on the odds of life forming on a planet. "I think [the chances] could be a lot lower, personally."
That's reinforced by another stark reality. "We haven't seen life everywhere we've looked so far," said astrobiologist Lauri Barge. "If life really requires some unique conditions to emerge, obviously Earth had them, but how many other planets would have them?"
So alien life might be out there, but there's a very good chance that it's not. Researchers are excited about either outcome and believe we're about to enter a golden age of planetary discovery. "Whether or not I'm optimistic that any life is out there, I am very optimistic that we're going to find out [either way]," NASA exoplanet researcher Shawn Domagal-Goldman told Engadget. "And I don't think we've ever had a moment like this in the history of our species."
Our prospects of finding alien life will explode in the next decade. NASA is on a tear hunting "exoplanets" -- planets orbiting stars outside our solar system -- with the satellites Spitzer, Hubble and particularly Kepler, launched in 2009. So far, the latter has discovered 2,335 exoplanets, 21 of which are in their star's habitable regions, and just the right size and mass for life. The most famous of those is Trappist-1, a seven-planet system discovered in February. It's just 40 light-years from Earth, and as many as three of its planets are in the "Goldilocks zone."
The Trappist-1 exoplanets will be one of the first targets of the $8.7 billion James Webb space telescope (JWST), set to launch in 2018. That instrument, parked a million miles from Earth, will be able to analyze the spectrum of exoplanet atmospheres to search for "biomarkers," or signs of life.
"If I was talking to you before [Trappist-1], I'd have said don't count on looking at the atmospheres of exoplanets, because you need darn-near-perfect targets," Domagal-Goldman said. "The Trappist planets are darn-near-perfect targets."
What exactly are we looking for?
Biologists don't even know how life sprang up on Earth, let alone elsewhere. It could have come via a process called abiogenesis, where life evolves via an electrochemical process from inert organic chemicals. Or it could have formed with "panspermia," in which simple life forms are ripped from one planet by a giant collision, survive a freezing ride through space and eventually collide into another planet, where they thrive anew. ("That's just outsourcing the problem," noted Scharf.)
We can't see exoplanets with a telescope -- they're too small, too far away and too overwhelmed by the light of their stars. If they pass in front of a star, however, Kepler can detect the star's dimming using the "transit method." Based on how much and how often the light dips, along with any wobble in the star, astronomers can figure out the planet's approximate size, mass and distance from its sun. Using stellar radiation models (that give the energy different stars emit) they can even estimate its surface temperature.
That's enough to figure out whether a planet is habitable. An ideal candidate has a temperature that supports liquid water and is less than twice the mass of Earth. That way, it's likely to have a rocky surface and gravity that won't crush nascent life.
Once a candidate is spotted, NASA will try to analyze its atmosphere. As it happens, Trappist-1 is an ideal study for the JWST because its relatively dim red dwarf star doesn't flood the planets around with light like larger stars do.
JWST's main instruments for sussing out Trappist-1 atmospheres will be its NIRCAM and NIRISS near-infrared cameras. When planets pass in front of the star, light will filter through their atmospheres and the instruments will pick out signature wavelengths of distinct chemicals. The cameras will particularly seek "biomarker" chemicals like ozone and methane (though that won't be easy), which usually exist only in the presence of organic life. Ozone, for one, is formed when oxygen produced by plants or phytoplankton is hit by ultraviolet light.
Either the presence or lack of an atmosphere on Trappist-1 will be of keen interest to scientists. "I want to know why those planets are uninhabitable," said Domagal-Goldman. "Is it because their atmospheres were stripped? Is it because they had some runaway greenhouse process that they never recovered from?"
The JWST won't be the only NASA instrument hunting life. The Transiting Exoplanet Survey Satellite (TESS) will also launch in 2018, searching for exoplanets around nearby stars. Like Kepler, it'll spot them using the transit method. Unlike Kepler, though, it'll scan very bright stars relatively close to Earth. Since those are up to 100 times more luminous than the ones observed by Kepler, it'll make follow-up observations by the JWST or Earth-based telescopes much easier, NASA said.
In the mid-2020s, NASA will launch WFIRST, a space telescope with a field of view 100 times wider than Hubble. That instrument will also do spectroscopic scans of exoplanets, but with much more detail than the JWST. Not only is it more powerful, it can better block out the glare of stars, giving it a clearer view of the exoplanets.
Along with those instruments, NASA is hunting exoplanets using the ground-based Large Binocular Telescope Interferometer, Spitzer Space Telescope and, yes, the Hubble Space Telescope. Its basic strategy is to find habitable exoplanet candidates using the transit method, then scan their atmospheres using spectroscopes via the erstwhile Hubble (recently repurposed for the task), JWST, WFIRST and large ground telescopes.
..... There's more, much more ...