Oct 29, 2020 11:13 PM
(This post was last modified: Oct 30, 2020 01:37 AM by C C.)
Saturn’s moon Titan may have the makings of early life
https://bgr.com/2020/10/28/life-on-titan-saturn-moon/
SUMMARY POINTS: Saturn’s bizarre moon Titan has carbon-based compounds in its atmosphere that may be a precursor to life. The surface of Titan is covered in lakes of hydrocarbons which are toxic to life as we know it, but there may be an ocean of liquid water deep beneath the surface. Future missions could probe that ocean in search of life. (MORE)
Where were Jupiter and Saturn born?
https://carnegiescience.edu/news/where-w...aturn-born
RELEASE: New work led by Carnegie’s Matt Clement reveals the likely original locations of Saturn and Jupiter. These findings refine our understanding of the forces that determined our Solar System’s unusual architecture, including the ejection of an additional planet between Saturn and Uranus, ensuring that only small, rocky planets, like Earth, formed inward of Jupiter.
In its youth, our Sun was surrounded by a rotating disk of gas and dust from which the planets were born. The orbits of early formed planets were thought to be initially close-packed and circular, but gravitational interactions between the larger objects perturbed the arrangement and caused the baby giant planets to rapidly reshuffle, creating the configuration we see today.
“We now know that there are thousands of planetary systems in our Milky Way galaxy alone,” Clement said. “But it turns out that the arrangement of planets in our own Solar System is highly unusual, so we are using models to reverse engineer and replicate its formative processes. This is a bit like trying to figure out what happened in a car crash after the fact—how fast were the cars going, in what directions, and so on.”
Clement and his co-authors—Carnegie’s John Chambers, Sean Raymond of the University of Bordeaux, Nathan Kaib of University of Oklahoma, Rogerio Deienno of the Southwest Research Institute, and André Izidoro of Rice University—conducted 6,000 simulations of our Solar System’s evolution, revealing an unexpected detail about Jupiter and Saturn’s original relationship. Jupiter in its infancy was thought to orbit the Sun three times for every two orbits that Saturn completed. But this arrangement is not able to satisfactorily explain the configuration of the giant planets that we see today. The team’s models showed that a ratio of two Jupiter orbits to one Saturnian orbit more consistently produced results that look like our familiar planetary architecture.
“This indicates that while our Solar System is a bit of an oddball, it wasn’t always the case,” explained Clement, who is presenting the team’s work at the American Astronomical Society’s Division for Planetary Sciences virtual meeting today. “What’s more, now that we’ve established the effectiveness of this model, we can use it to help us look at the formation of the terrestrial planets, including our own, and to perhaps inform our ability to look for similar systems elsewhere that could have the potential to host life.”
The model also showed that the positions of Uranus and Neptune were shaped by the mass of the Kuiper belt—an icy region on the Solar System’s edges composed of dwarf planets and planetoids of which Pluto is the largest member—and by an ice giant planet that was kicked out in the Solar System’s infancy.
Mars-sized rogue planet found drifting through the Milky Way
https://www.upi.com/Science_News/2020/10...657/?ur3=1
RELEASE: Astronomers have discovered a planetary free agent floating through the Milky Way, unbound to the gravity of any nearby stars. The discovery, detailed Thursday in Astrophysical Journal Letters, suggests the Milky Way may be teeming with rogue planets. The new exoplanet, the smallest free-floating planet astronomers have found, is too small to be directly observed.
Researchers were able to spot the rogue world -- which is somewhere between the size of Mars and Earth -- with the assistance of a microlensing event. "If a massive object -- a star or a planet -- passes between an Earth-based observer and a distant source star, its gravity may deflect and focus light from the source," lead study author Przemek Mroz, a postdoctoral scholar at the California Institute of Technology, said in a news release. "The observer will measure a short brightening of the source star."
"Chances of observing microlensing are extremely slim because three objects -- source, lens, and observer -- must be nearly perfectly aligned," Mroz said. "If we observed only one source star, we would have to wait almost a million years to see the source being microlensed."
To increase their odds of locating microlensing events, researchers rely on surveys. In this instance, astronomers utilized data collected by the OGLE survey, featuring a Chilean telescope and led by a team of astronomers at Warsaw University in Poland. Every night, the OGLE survey's 1.3-meter Warsaw Telescope scans the Milky Way center, home to hundreds of millions of stars, looking for changes in stellar brightness. Thankfully, microlensing detection doesn't depend on the lensing object's brightness. It's the lensing object's mass that matters. The more massive the lensing object, the longer the microlensing event lasts. The microlensing event caused by the recently discovered rogue planet lasted just a few hours.
Researchers were able to calculate the mass of the rogue planet by measuring the light curve and duration of the microlensing event. "When we first spotted this event, it was clear that it must have been caused by an extremely tiny object," said study co-author Radoslaw Poleski, researcher at the Astronomical Observatory of the University of Warsaw.
Researchers were able to determine that the lensing object was likely less massive than Earth and about the same size as Mars. Astronomers were also able to determine that the object was without a host star. "If the lens were orbiting a star, we would detect its presence in the light curve of the event," said Poleski. "We can rule out the planet having a star within about 8 astronomical units -- the astronomical unit is the distance between the Earth and the sun."
Since OGLE found the first rogue exoplanet several years ago, the survey has discovered several planetary free agents floating through the Milky Way, but the latest -- dubbed OGLE-2016-BLG-1928 -- is the smallest rogue planet scientists have found. "Our discovery demonstrates that low-mass free-floating planets can be detected and characterized using ground-based telescopes," said Andrzej Udalski, principle investigator on the OGLE project.
Astronomers estimate rogue worlds were initially formed around stars inside protoplanetary disks, but were ejected by gravitational interactions with other young planets. By studying the size distribution of rogue planets, scientists expect to gain a greater understanding of planetary formation and evolution. RELATED: When Worlds Collide
https://www.youtube-nocookie.com/embed/20zdwdFwQEA
https://bgr.com/2020/10/28/life-on-titan-saturn-moon/
SUMMARY POINTS: Saturn’s bizarre moon Titan has carbon-based compounds in its atmosphere that may be a precursor to life. The surface of Titan is covered in lakes of hydrocarbons which are toxic to life as we know it, but there may be an ocean of liquid water deep beneath the surface. Future missions could probe that ocean in search of life. (MORE)
Where were Jupiter and Saturn born?
https://carnegiescience.edu/news/where-w...aturn-born
RELEASE: New work led by Carnegie’s Matt Clement reveals the likely original locations of Saturn and Jupiter. These findings refine our understanding of the forces that determined our Solar System’s unusual architecture, including the ejection of an additional planet between Saturn and Uranus, ensuring that only small, rocky planets, like Earth, formed inward of Jupiter.
In its youth, our Sun was surrounded by a rotating disk of gas and dust from which the planets were born. The orbits of early formed planets were thought to be initially close-packed and circular, but gravitational interactions between the larger objects perturbed the arrangement and caused the baby giant planets to rapidly reshuffle, creating the configuration we see today.
“We now know that there are thousands of planetary systems in our Milky Way galaxy alone,” Clement said. “But it turns out that the arrangement of planets in our own Solar System is highly unusual, so we are using models to reverse engineer and replicate its formative processes. This is a bit like trying to figure out what happened in a car crash after the fact—how fast were the cars going, in what directions, and so on.”
Clement and his co-authors—Carnegie’s John Chambers, Sean Raymond of the University of Bordeaux, Nathan Kaib of University of Oklahoma, Rogerio Deienno of the Southwest Research Institute, and André Izidoro of Rice University—conducted 6,000 simulations of our Solar System’s evolution, revealing an unexpected detail about Jupiter and Saturn’s original relationship. Jupiter in its infancy was thought to orbit the Sun three times for every two orbits that Saturn completed. But this arrangement is not able to satisfactorily explain the configuration of the giant planets that we see today. The team’s models showed that a ratio of two Jupiter orbits to one Saturnian orbit more consistently produced results that look like our familiar planetary architecture.
“This indicates that while our Solar System is a bit of an oddball, it wasn’t always the case,” explained Clement, who is presenting the team’s work at the American Astronomical Society’s Division for Planetary Sciences virtual meeting today. “What’s more, now that we’ve established the effectiveness of this model, we can use it to help us look at the formation of the terrestrial planets, including our own, and to perhaps inform our ability to look for similar systems elsewhere that could have the potential to host life.”
The model also showed that the positions of Uranus and Neptune were shaped by the mass of the Kuiper belt—an icy region on the Solar System’s edges composed of dwarf planets and planetoids of which Pluto is the largest member—and by an ice giant planet that was kicked out in the Solar System’s infancy.
Mars-sized rogue planet found drifting through the Milky Way
https://www.upi.com/Science_News/2020/10...657/?ur3=1
RELEASE: Astronomers have discovered a planetary free agent floating through the Milky Way, unbound to the gravity of any nearby stars. The discovery, detailed Thursday in Astrophysical Journal Letters, suggests the Milky Way may be teeming with rogue planets. The new exoplanet, the smallest free-floating planet astronomers have found, is too small to be directly observed.
Researchers were able to spot the rogue world -- which is somewhere between the size of Mars and Earth -- with the assistance of a microlensing event. "If a massive object -- a star or a planet -- passes between an Earth-based observer and a distant source star, its gravity may deflect and focus light from the source," lead study author Przemek Mroz, a postdoctoral scholar at the California Institute of Technology, said in a news release. "The observer will measure a short brightening of the source star."
"Chances of observing microlensing are extremely slim because three objects -- source, lens, and observer -- must be nearly perfectly aligned," Mroz said. "If we observed only one source star, we would have to wait almost a million years to see the source being microlensed."
To increase their odds of locating microlensing events, researchers rely on surveys. In this instance, astronomers utilized data collected by the OGLE survey, featuring a Chilean telescope and led by a team of astronomers at Warsaw University in Poland. Every night, the OGLE survey's 1.3-meter Warsaw Telescope scans the Milky Way center, home to hundreds of millions of stars, looking for changes in stellar brightness. Thankfully, microlensing detection doesn't depend on the lensing object's brightness. It's the lensing object's mass that matters. The more massive the lensing object, the longer the microlensing event lasts. The microlensing event caused by the recently discovered rogue planet lasted just a few hours.
Researchers were able to calculate the mass of the rogue planet by measuring the light curve and duration of the microlensing event. "When we first spotted this event, it was clear that it must have been caused by an extremely tiny object," said study co-author Radoslaw Poleski, researcher at the Astronomical Observatory of the University of Warsaw.
Researchers were able to determine that the lensing object was likely less massive than Earth and about the same size as Mars. Astronomers were also able to determine that the object was without a host star. "If the lens were orbiting a star, we would detect its presence in the light curve of the event," said Poleski. "We can rule out the planet having a star within about 8 astronomical units -- the astronomical unit is the distance between the Earth and the sun."
Since OGLE found the first rogue exoplanet several years ago, the survey has discovered several planetary free agents floating through the Milky Way, but the latest -- dubbed OGLE-2016-BLG-1928 -- is the smallest rogue planet scientists have found. "Our discovery demonstrates that low-mass free-floating planets can be detected and characterized using ground-based telescopes," said Andrzej Udalski, principle investigator on the OGLE project.
Astronomers estimate rogue worlds were initially formed around stars inside protoplanetary disks, but were ejected by gravitational interactions with other young planets. By studying the size distribution of rogue planets, scientists expect to gain a greater understanding of planetary formation and evolution. RELATED: When Worlds Collide