May 20, 2016 01:49 AM
Extraterrestrial oceans: Beneath the surface
https://www.sciencedaily.com/releases/20...082050.htm
RELEASE: Icy objects in our solar system have large oceans under their surfaces and here life could evolve and flourish. So says a new thesis by Jesper Lindkvist, PhD student at the Swedish Institute of Space Physics and Umeå University. The thesis will be defended on Tuesday 31 May at the Swedish Institute of Space Physics in Kiruna, Sweden.
There has long been speculation as to whether Jupiter's large, icy moon Callisto has an ocean beneath its surface. Observations of Callisto's near-space environment by instruments on board the spacecraft Galileo, which is orbiting Jupiter, lead us to believe that there is such a sub-surface ocean. Computer simulations of the space plasma interactions support this belief.
"If you find an ocean beneath the surface of one moon, perhaps the same is true of other icy objects in space," says Jesper Lindkvist.
Outflow of water vapour has been detected from the surface of the dwarf planet Ceres, which is in the asteroid belt between Mars and Jupiter. This could indicate a reservoir of water, also related to a large sea beneath the surface. The spacecraft Dawn is at Ceres right now, trying to answer this question.
"If someone was planning to build a future space base on one of these Solar System objects, for example to seek after signs of life, I would suggest they take an extra long ice bore and their fishing equipment," jokes Jesper Lindkvist.
The outflow of water vapour from moons and dwarf planets is similar to that we see from comets. The icy comet 67P/Churyumov-Gerasimenko which rounded the sun in the summer of 2015 has been followed closely by the European spacecraft Rosetta. Measurements of the space environment round it show that the water flowing out from the comet's nucleus forms a prominent atmosphere which interacts with the constant flow of ionised particles from the sun, the so-called solar wind.
"Understanding their origin and how icy bodies evolve is one more piece of the puzzle we need to lay in order to explain the origin of our Solar System and its eventual fate," says Jesper Lindkvist.
Jesper Lindkvist comes from the town of Vidsel in Northern Sweden. He has a Masters degree in engineering physics from Luleå University of Technology.
Thesis defence
On Tuesday 31 May Jesper Lindkvist of the Swedish Institute of Space Physics in Kiruna and the Department of Physics at Umeå University will defend his PhD thesis entitled Plasma Interactions with Icy Bodies in the Solar System.
The thesis defence will take place at 9 am in the Aula at the Swedish Institute of Space Physics in Kiruna.
The thesis opponent is Dr Elias Roussos, Max Planck Institute for Solar System Research, Göttingen, Germany. The candidate's supervisors are Assoc. Prof. Mats Holmström and Dr Martin Wieser at the Swedish Institute of Space Physics, Kiruna.
Ancient tsunami evidence on Mars reveals life potential
https://www.sciencedaily.com/releases/20...101756.htm
RELEASE: The geologic shape of what were once shorelines through Mars' northern plains convinces scientists that two large meteorites -- hitting the planet millions of years apart -- triggered a pair of mega-tsunamis. These gigantic waves forever scarred the Martian landscape and yielded evidence of cold, salty oceans conducive to sustaining life.
"About 3.4 billion years ago, a big meteorite impact triggered the first tsunami wave. This wave was composed of liquid water. It formed widespread backwash channels to carry the water back to the ocean," said Alberto Fairén, Cornell visiting scientist in astronomy and principal investigator at the Center of Astrobiology, Madrid.
Fairén, who with lead author Alexis Rodriguez of the Planetary Science Institute and 12 others, published their work in Scientific Reports (May 19), a publication of the journal Nature.
The scientists found evidence for another big meteorite impact, which triggered a second tsunami wave. In the millions of years between the two meteorite impacts and their associated mega-tsunamis, Mars went through frigid climate change, where water turned to ice, Fairén said: "The ocean level receded from its original shoreline to form a secondary shoreline, because the climate had become significantly colder."
The second tsunami formed rounded lobes of ice. "These lobes froze on the land as they reached their maximum extent and the ice never went back to the ocean -- which implies the ocean was at least partially frozen at that time," he said. "Our paper provides very solid evidence for the existence of very cold oceans on early Mars. It is difficult to imagine Californian beaches on ancient Mars, but try to picture the Great Lakes on a particularly cold and long winter, and that could be a more accurate image of water forming seas and oceans on ancient Mars."
These icy lobes retained their well-defined boundaries and their flow-related shapes, Fairén said, suggesting the frozen ancient ocean was briny. "Cold, salty waters may offer a refuge for life in extreme environments, as the salts could help keep the water liquid. … If life existed on Mars, these icy tsunami lobes are very good candidates to search for biosignatures," he said.
"We have already identified some areas inundated by the tsunamis where the ponded water appears to have emplaced lacustrine sediments, including evaporites," Rodriguez said. "As a follow-up investigation we plan to characterize these terrains and assess their potential for future robotic or human in-situ exploration."
The research, "Tsunami Waves Extensively Resurfaced the Shorelines of an Early Martian Ocean," was funded by NASA. Fairén was supported by the European Research Council.
Photonics advances allow us to be seen across the universe, with major implications for search for extraterrestrial intelligence
https://www.sciencedaily.com/releases/20...125551.htm
RELEASE: Looking up at the night sky -- expansive and seemingly endless, stars and constellations blinking and glimmering like jewels just out of reach -- it's impossible not to wonder: Are we alone?
For many of us, the notion of intelligent life on other planets is as captivating as ideas come. Maybe in some other star system, maybe a billion light years away, there's a civilization like ours asking the exact same question.
Imagine if we sent up a visible signal that could eventually be seen across the entire universe. Imagine if another civilization did the same.
The technology now exists to enable exactly that scenario, according to UC Santa Barbara physics professor Philip Lubin, whose new work applies his research and advances in directed-energy systems to the search for extraterrestrial intelligence (SETI). His recent paper "The Search for Directed Intelligence" appears in the journal REACH -- Reviews in Human Space Exploration.
"If even one other civilization existed in our galaxy and had a similar or more advanced level of directed-energy technology, we could detect 'them' anywhere in our galaxy with a very modest detection approach," said Lubin, who leads the UCSB Experimental Cosmology Group. "If we scale it up as we're doing with direct energy systems, how far could we detect a civilization equivalent to ours? The answer becomes that the entire universe is now open to us.
"Similar to the use of directed energy for relativistic interstellar probes and planetary defense that we have been developing, take that same technology and ask yourself, 'What are consequences of that technology in terms of us being detectable by another 'us' in some other part of the universe?'" Lubin added. "Could we see each other? Can we behave as a lighthouse, or a beacon, and project our presence to some other civilization somewhere else in the universe? The profound consequences are, of course, 'Where are they?' Perhaps they are shy like us and do not want to be seen, or they don't transmit in a way we can detect, or perhaps 'they' do not exist."
The same directed energy technology is at the core of Lubin's recent efforts to develop miniscule, laser-powered interstellar spacecraft. That work, funded since 2015 by NASA (and just selected by the space agency for "Phase II" support) is the technology behind billionaire Yuri Milner's newsmaking, $100-million Breakthrough Starshot initiative announced April 12.
Lubin is a scientific advisor on Starshot, which is using his NASA research as a roadmap as it seeks to send tiny spacecraft to nearby star systems.
In describing directed energy, Lubin likened the process to using the force of water from a garden hose to push a ball forward. Using a laser light, spacecraft can be pushed and steered in much the same way. Applied to SETI, he said, the directed energy system could be deployed to send a targeted signal to other planetary systems.
"In our paper, we propose a search strategy that will observe nearly 100 billion planets, allowing us to test our hypothesis that other similarly or more advanced civilizations with this same broadcast capability exist," Lubin said.
"As a species we are evolving rapidly in photonics, the production and manipulation of light," he explained. "Our recent paper explores the hypothesis: We now have the ability to produce light extremely efficiently, and perhaps other species might also have that ability. And if so, then what would be the implications of that? This paper explores the 'if so, then what?'"
Traditionally and still, Lubin said, the "mainstay of the SETI community" has been to conduct searches via radio waves. Think Jodie Foster in "Contact," receiving an extraterrestrial signal by way of a massive and powerful radio telescope. With Lubin's UCSB-developed photonics approach, however, making "contact" could be much simpler: Take the right pictures and see if any distant systems are beaconing us.
"All discussions of SETI have to have a significant level of, maybe not humor, but at least hubris as to what makes reason and what doesn't," Lubin said. "Maybe we are alone in terms of our technological capability. Maybe all that's out there is bacteria or viruses. We have no idea because we've never found life outside of our Earth.
"But suppose there is a civilization like ours and suppose -- unlike us, who are skittish about broadcasting our presence -- they think it's important to be a beacon, an interstellar or extragalactic lighthouse of sorts," he added. "There is a photonics revolution going on on Earth that enables this specific kind of transmission of information via visible or near-infrared light of high intensity. And you don't need a large telescope to begin these searches. You could detect a presence like our current civilization anywhere in our galaxy, where there are 100 billion possible planets, with something in your backyard. Put in context, and we would love to have people really think about this: You can literally go out with your camera from Costco, take pictures of the sky, and if you knew what you were doing you could mount a SETI search in your backyard. The lighthouse is that bright."
https://www.sciencedaily.com/releases/20...082050.htm
RELEASE: Icy objects in our solar system have large oceans under their surfaces and here life could evolve and flourish. So says a new thesis by Jesper Lindkvist, PhD student at the Swedish Institute of Space Physics and Umeå University. The thesis will be defended on Tuesday 31 May at the Swedish Institute of Space Physics in Kiruna, Sweden.
There has long been speculation as to whether Jupiter's large, icy moon Callisto has an ocean beneath its surface. Observations of Callisto's near-space environment by instruments on board the spacecraft Galileo, which is orbiting Jupiter, lead us to believe that there is such a sub-surface ocean. Computer simulations of the space plasma interactions support this belief.
"If you find an ocean beneath the surface of one moon, perhaps the same is true of other icy objects in space," says Jesper Lindkvist.
Outflow of water vapour has been detected from the surface of the dwarf planet Ceres, which is in the asteroid belt between Mars and Jupiter. This could indicate a reservoir of water, also related to a large sea beneath the surface. The spacecraft Dawn is at Ceres right now, trying to answer this question.
"If someone was planning to build a future space base on one of these Solar System objects, for example to seek after signs of life, I would suggest they take an extra long ice bore and their fishing equipment," jokes Jesper Lindkvist.
The outflow of water vapour from moons and dwarf planets is similar to that we see from comets. The icy comet 67P/Churyumov-Gerasimenko which rounded the sun in the summer of 2015 has been followed closely by the European spacecraft Rosetta. Measurements of the space environment round it show that the water flowing out from the comet's nucleus forms a prominent atmosphere which interacts with the constant flow of ionised particles from the sun, the so-called solar wind.
"Understanding their origin and how icy bodies evolve is one more piece of the puzzle we need to lay in order to explain the origin of our Solar System and its eventual fate," says Jesper Lindkvist.
Jesper Lindkvist comes from the town of Vidsel in Northern Sweden. He has a Masters degree in engineering physics from Luleå University of Technology.
Thesis defence
On Tuesday 31 May Jesper Lindkvist of the Swedish Institute of Space Physics in Kiruna and the Department of Physics at Umeå University will defend his PhD thesis entitled Plasma Interactions with Icy Bodies in the Solar System.
The thesis defence will take place at 9 am in the Aula at the Swedish Institute of Space Physics in Kiruna.
The thesis opponent is Dr Elias Roussos, Max Planck Institute for Solar System Research, Göttingen, Germany. The candidate's supervisors are Assoc. Prof. Mats Holmström and Dr Martin Wieser at the Swedish Institute of Space Physics, Kiruna.
Ancient tsunami evidence on Mars reveals life potential
https://www.sciencedaily.com/releases/20...101756.htm
RELEASE: The geologic shape of what were once shorelines through Mars' northern plains convinces scientists that two large meteorites -- hitting the planet millions of years apart -- triggered a pair of mega-tsunamis. These gigantic waves forever scarred the Martian landscape and yielded evidence of cold, salty oceans conducive to sustaining life.
"About 3.4 billion years ago, a big meteorite impact triggered the first tsunami wave. This wave was composed of liquid water. It formed widespread backwash channels to carry the water back to the ocean," said Alberto Fairén, Cornell visiting scientist in astronomy and principal investigator at the Center of Astrobiology, Madrid.
Fairén, who with lead author Alexis Rodriguez of the Planetary Science Institute and 12 others, published their work in Scientific Reports (May 19), a publication of the journal Nature.
The scientists found evidence for another big meteorite impact, which triggered a second tsunami wave. In the millions of years between the two meteorite impacts and their associated mega-tsunamis, Mars went through frigid climate change, where water turned to ice, Fairén said: "The ocean level receded from its original shoreline to form a secondary shoreline, because the climate had become significantly colder."
The second tsunami formed rounded lobes of ice. "These lobes froze on the land as they reached their maximum extent and the ice never went back to the ocean -- which implies the ocean was at least partially frozen at that time," he said. "Our paper provides very solid evidence for the existence of very cold oceans on early Mars. It is difficult to imagine Californian beaches on ancient Mars, but try to picture the Great Lakes on a particularly cold and long winter, and that could be a more accurate image of water forming seas and oceans on ancient Mars."
These icy lobes retained their well-defined boundaries and their flow-related shapes, Fairén said, suggesting the frozen ancient ocean was briny. "Cold, salty waters may offer a refuge for life in extreme environments, as the salts could help keep the water liquid. … If life existed on Mars, these icy tsunami lobes are very good candidates to search for biosignatures," he said.
"We have already identified some areas inundated by the tsunamis where the ponded water appears to have emplaced lacustrine sediments, including evaporites," Rodriguez said. "As a follow-up investigation we plan to characterize these terrains and assess their potential for future robotic or human in-situ exploration."
The research, "Tsunami Waves Extensively Resurfaced the Shorelines of an Early Martian Ocean," was funded by NASA. Fairén was supported by the European Research Council.
Photonics advances allow us to be seen across the universe, with major implications for search for extraterrestrial intelligence
https://www.sciencedaily.com/releases/20...125551.htm
RELEASE: Looking up at the night sky -- expansive and seemingly endless, stars and constellations blinking and glimmering like jewels just out of reach -- it's impossible not to wonder: Are we alone?
For many of us, the notion of intelligent life on other planets is as captivating as ideas come. Maybe in some other star system, maybe a billion light years away, there's a civilization like ours asking the exact same question.
Imagine if we sent up a visible signal that could eventually be seen across the entire universe. Imagine if another civilization did the same.
The technology now exists to enable exactly that scenario, according to UC Santa Barbara physics professor Philip Lubin, whose new work applies his research and advances in directed-energy systems to the search for extraterrestrial intelligence (SETI). His recent paper "The Search for Directed Intelligence" appears in the journal REACH -- Reviews in Human Space Exploration.
"If even one other civilization existed in our galaxy and had a similar or more advanced level of directed-energy technology, we could detect 'them' anywhere in our galaxy with a very modest detection approach," said Lubin, who leads the UCSB Experimental Cosmology Group. "If we scale it up as we're doing with direct energy systems, how far could we detect a civilization equivalent to ours? The answer becomes that the entire universe is now open to us.
"Similar to the use of directed energy for relativistic interstellar probes and planetary defense that we have been developing, take that same technology and ask yourself, 'What are consequences of that technology in terms of us being detectable by another 'us' in some other part of the universe?'" Lubin added. "Could we see each other? Can we behave as a lighthouse, or a beacon, and project our presence to some other civilization somewhere else in the universe? The profound consequences are, of course, 'Where are they?' Perhaps they are shy like us and do not want to be seen, or they don't transmit in a way we can detect, or perhaps 'they' do not exist."
The same directed energy technology is at the core of Lubin's recent efforts to develop miniscule, laser-powered interstellar spacecraft. That work, funded since 2015 by NASA (and just selected by the space agency for "Phase II" support) is the technology behind billionaire Yuri Milner's newsmaking, $100-million Breakthrough Starshot initiative announced April 12.
Lubin is a scientific advisor on Starshot, which is using his NASA research as a roadmap as it seeks to send tiny spacecraft to nearby star systems.
In describing directed energy, Lubin likened the process to using the force of water from a garden hose to push a ball forward. Using a laser light, spacecraft can be pushed and steered in much the same way. Applied to SETI, he said, the directed energy system could be deployed to send a targeted signal to other planetary systems.
"In our paper, we propose a search strategy that will observe nearly 100 billion planets, allowing us to test our hypothesis that other similarly or more advanced civilizations with this same broadcast capability exist," Lubin said.
"As a species we are evolving rapidly in photonics, the production and manipulation of light," he explained. "Our recent paper explores the hypothesis: We now have the ability to produce light extremely efficiently, and perhaps other species might also have that ability. And if so, then what would be the implications of that? This paper explores the 'if so, then what?'"
Traditionally and still, Lubin said, the "mainstay of the SETI community" has been to conduct searches via radio waves. Think Jodie Foster in "Contact," receiving an extraterrestrial signal by way of a massive and powerful radio telescope. With Lubin's UCSB-developed photonics approach, however, making "contact" could be much simpler: Take the right pictures and see if any distant systems are beaconing us.
"All discussions of SETI have to have a significant level of, maybe not humor, but at least hubris as to what makes reason and what doesn't," Lubin said. "Maybe we are alone in terms of our technological capability. Maybe all that's out there is bacteria or viruses. We have no idea because we've never found life outside of our Earth.
"But suppose there is a civilization like ours and suppose -- unlike us, who are skittish about broadcasting our presence -- they think it's important to be a beacon, an interstellar or extragalactic lighthouse of sorts," he added. "There is a photonics revolution going on on Earth that enables this specific kind of transmission of information via visible or near-infrared light of high intensity. And you don't need a large telescope to begin these searches. You could detect a presence like our current civilization anywhere in our galaxy, where there are 100 billion possible planets, with something in your backyard. Put in context, and we would love to have people really think about this: You can literally go out with your camera from Costco, take pictures of the sky, and if you knew what you were doing you could mount a SETI search in your backyard. The lighthouse is that bright."