Aug 25, 2021 07:20 AM
(This post was last modified: Aug 25, 2021 07:24 AM by C C.)
The astrobiological potential of rogue planets
https://www.airspacemag.com/daily-planet...180978507/
INTRO: When we think about extraterrestrial life on another planet, one common assumption is that we’re talking about a planet orbiting a star, which provides it with the necessary energy. However, that may not always be so. In a new paper, Alberto Fairén from the Center of Astrobiology in Madrid, Spain, and I look into the possibility that planets wandering through interstellar space could also host life. These “rogue” planets may have been ejected out of their original solar system during the early, chaotic phase of planetary formation.
There are two general types of rogue planets: gas giants like Saturn and Neptune, and rocky Earthlike planets. While the chances for life on gas giants is extremely remote, rocky migrating planets could in principle host microbial life. To do that, they would need internal heat from the decay of radioactive elements that keep water—or some other suitable solvent—liquid beneath a frozen surface.
This is similar to what we believe happens on Jupiter’s moon Europa, where chemical, thermal, or even osmotic gradients could act as a life-sustaining energy source. If the planet is really large and there is more radiogenic heat available than on Earth, the planet could also retain a thick hydrogen or nitrogen atmosphere, which may make life feasible.
There is even more to the astrobiological potential of rogue planets, however. Not only could they hold microbial life bottled up in their subsurface, they may be able to distribute life throughout the galaxy. In our paper we suggest two ways that this kind of panspermia might occur... (MORE)
This report could make or break the next 30 years of US astronomy
https://www.space.com/astro2020-report-n...-astronomy
EXCERPTS: In the U.S., astronomers have managed these competing ambitions by devising a process that has become the envy of the scientific world: the Astronomy and Astrophysics Decadal Survey, a once-in-10-years exercise that recommends and ranks the community's priorities for the next decade — embodied, eventually, by major new federally-sponsored observatories on the ground and in space. Projects such as NASA's Hubble Space Telescope owe their existence, in part, to coveted endorsements from Decadals of yore, and the practice has spread to several other disciplines that now undertake Decadal Surveys of their own.
Organized by the National Academies of Sciences, Engineering, and Medicine, six Decadal Surveys have set the course of U.S. astronomy since they began in the 1960s. The results of the seventh, dubbed Astro2020, will soon be announced after two years of exhaustive deliberations led by a 20-member steering committee. And just like its predecessors, Astro2020 will reveal where major new investments and discoveries are most likely to be made — and where neglect, disinterest or even fear may block progress for generations to come.
[...] For more than a few astronomers, a drab name like "the Decadal" does not properly capture a process that holds such sway over their destiny. Instead they sometimes just call it "the voice of God." In coming weeks, when Astro2020's final report is released, that voice — that supposedly communal voice — will once again speak. Yet outside of a chosen few, sworn to secrecy, no one in the community knows in advance what it will say. Everyone, though, agrees Astro2020's conclusions arrive at a time of peril.
"We are right now on a knife-edge," says John O'Meara, chief scientist of the W. M. Keck Observatory on Mauna Kea in Hawaii. "I do believe this Decadal is existential for astronomy in the United States. When you consider the facilities and the science topics that are under discussion, it will influence whether or not we become a second-place player in global astronomy…. When the [federal] agencies and Congress receive the Decadal report, they will hold in their hands the decision of whether or not we wish to have leadership in this field of science."
From the outside looking in, one would not realize the enterprise of U.S. astronomy is teetering on the edge of crisis [...] Europe, in contrast, took the lead over the U.S. in ground-based optical astronomy years ago and is well into construction of an ELT of its own in Chile. The European Extremely Large Telescope boasts a 40-meter mirror — and it is projected to come online in 2027.
China is surging ahead as well. For evidence, look no further than the U.S.'s iconic, National Science Foundation-funded Arecibo radio telescope in Puerto Rico: Once the world's largest, the radio telescope catastrophically collapsed last year in part because of budgetary neglect — but not before China's Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) had superseded it in size. And together — without the U.S. — Europe, China and many other international partners are building the Square Kilometer Array (SKA), a breathtakingly powerful collection of thousands of radio telescopes that is set to become fully operational at sites in Australia and South Africa as early as 2030... (MORE - details)
https://www.airspacemag.com/daily-planet...180978507/
INTRO: When we think about extraterrestrial life on another planet, one common assumption is that we’re talking about a planet orbiting a star, which provides it with the necessary energy. However, that may not always be so. In a new paper, Alberto Fairén from the Center of Astrobiology in Madrid, Spain, and I look into the possibility that planets wandering through interstellar space could also host life. These “rogue” planets may have been ejected out of their original solar system during the early, chaotic phase of planetary formation.
There are two general types of rogue planets: gas giants like Saturn and Neptune, and rocky Earthlike planets. While the chances for life on gas giants is extremely remote, rocky migrating planets could in principle host microbial life. To do that, they would need internal heat from the decay of radioactive elements that keep water—or some other suitable solvent—liquid beneath a frozen surface.
This is similar to what we believe happens on Jupiter’s moon Europa, where chemical, thermal, or even osmotic gradients could act as a life-sustaining energy source. If the planet is really large and there is more radiogenic heat available than on Earth, the planet could also retain a thick hydrogen or nitrogen atmosphere, which may make life feasible.
There is even more to the astrobiological potential of rogue planets, however. Not only could they hold microbial life bottled up in their subsurface, they may be able to distribute life throughout the galaxy. In our paper we suggest two ways that this kind of panspermia might occur... (MORE)
This report could make or break the next 30 years of US astronomy
https://www.space.com/astro2020-report-n...-astronomy
EXCERPTS: In the U.S., astronomers have managed these competing ambitions by devising a process that has become the envy of the scientific world: the Astronomy and Astrophysics Decadal Survey, a once-in-10-years exercise that recommends and ranks the community's priorities for the next decade — embodied, eventually, by major new federally-sponsored observatories on the ground and in space. Projects such as NASA's Hubble Space Telescope owe their existence, in part, to coveted endorsements from Decadals of yore, and the practice has spread to several other disciplines that now undertake Decadal Surveys of their own.
Organized by the National Academies of Sciences, Engineering, and Medicine, six Decadal Surveys have set the course of U.S. astronomy since they began in the 1960s. The results of the seventh, dubbed Astro2020, will soon be announced after two years of exhaustive deliberations led by a 20-member steering committee. And just like its predecessors, Astro2020 will reveal where major new investments and discoveries are most likely to be made — and where neglect, disinterest or even fear may block progress for generations to come.
[...] For more than a few astronomers, a drab name like "the Decadal" does not properly capture a process that holds such sway over their destiny. Instead they sometimes just call it "the voice of God." In coming weeks, when Astro2020's final report is released, that voice — that supposedly communal voice — will once again speak. Yet outside of a chosen few, sworn to secrecy, no one in the community knows in advance what it will say. Everyone, though, agrees Astro2020's conclusions arrive at a time of peril.
"We are right now on a knife-edge," says John O'Meara, chief scientist of the W. M. Keck Observatory on Mauna Kea in Hawaii. "I do believe this Decadal is existential for astronomy in the United States. When you consider the facilities and the science topics that are under discussion, it will influence whether or not we become a second-place player in global astronomy…. When the [federal] agencies and Congress receive the Decadal report, they will hold in their hands the decision of whether or not we wish to have leadership in this field of science."
From the outside looking in, one would not realize the enterprise of U.S. astronomy is teetering on the edge of crisis [...] Europe, in contrast, took the lead over the U.S. in ground-based optical astronomy years ago and is well into construction of an ELT of its own in Chile. The European Extremely Large Telescope boasts a 40-meter mirror — and it is projected to come online in 2027.
China is surging ahead as well. For evidence, look no further than the U.S.'s iconic, National Science Foundation-funded Arecibo radio telescope in Puerto Rico: Once the world's largest, the radio telescope catastrophically collapsed last year in part because of budgetary neglect — but not before China's Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) had superseded it in size. And together — without the U.S. — Europe, China and many other international partners are building the Square Kilometer Array (SKA), a breathtakingly powerful collection of thousands of radio telescopes that is set to become fully operational at sites in Australia and South Africa as early as 2030... (MORE - details)