Mar 10, 2021 08:30 PM
(This post was last modified: Mar 11, 2021 05:53 AM by C C.)
Comets Are More Dangerous Than We Thought
https://nautil.us/issue/98/mind/comets-a...we-thought
EXCRPTS: . . . Now comets, as you may know, come from far away, and spend little time in the inner solar system. Scientists, based on decades of work, consider it to be a minor risk for one to collide with Earth. A new study, however, hints that comets pose a much greater threat than previously thought. Specifically, it’s the long-period, rather than the short-period ones, we have to look out for. [...] Long-period comets are the least likely to hit our planet because they visit the inner solar system rarely (often just once) and zip by so quickly that the Earth is a tiny target. They originate in the Oort cloud...
[...] In the new study, published in Scientific Reports, Harvard astrophysicists Amir Siraj and Avi Loeb (yes, the backer of that controversial hypothesis about aliens) add a wrinkle to this story. They calculate that about 20 percent of long-period comets that pass within Earth’s orbit pass so close to the sun that they are torn apart by tidal forces. This process creates long strands of comet fragments that vastly increase the odds of collision with the Earth.
[...] Scientists know several groups of comets that are likely tidal fragments. For example, the Kreutz group contains thousands of comets stretched along similar orbits around the sun that are thought to be the remnants of a single giant comet that disrupted a thousand or more years ago... (MORE - details)
The asteroid belt: Wreckage of a destroyed planet or something else?
https://astronomy.com/news/2021/03/the-a...thing-else
EXCERPT: Billions of years ago, our solar system was far from being a stable and organized place. Planets were still forming, throwing their neighbor’s orbits out of whack in the process. In light of all this action, some astronomers used to believe a planet that orbited our Sun between the trajectories of Mars and Jupiter was blasted into pieces and formed the asteroid belt that floats in space today.
Scientists thought that "maybe there was a planet there and it got blown to smithereens,” explains Sean Raymond, an astronomer at the Astrophysical Laboratory of Bordeaux, in France. But after researchers began to examine the patterns in iron meteorites that fell to the Earth as meteors, Raymond says, it became clear they didn’t come from one parent body.
As a result, the thinking began to shift toward the idea that the asteroid belt was full of planetesimals, or pieces of a planet that either hadn’t formed or failed to form. But the trouble with this theory is that there just isn’t enough material in the belt to create such a mass. Ceres is the single largest asteroid in the belt, roughly the size of Australia with a mass nearly half that of all the material of the belt, according to Raymond. “It’s like tiny little crumbs,” Raymond says.
Just because the asteroid belt doesn’t represent the leftovers of a former planet doesn’t mean scientists have abandoned the idea entirely. The belt might have come from parts of other planets that still exist, or be part of a planetesimal — which is like a baby planet — that never completely formed before being smashed apart. “It used to be kind of a simple story, but in recent years it’s gotten increasingly more complicated as we learn more about planet formation,” [William] Bottke says... (MORE - details)
Russia says it will work with China on a Moon base (the "because fascism & Marxism are bedfellows at a deeper level" category)
https://arstechnica.com/science/2021/03/...r-station/
INTRO: The heads of the Chinese and Russian space agencies signed an agreement on Tuesday to work together to build a "scientific" station on the Moon. Under terms of a memorandum of understanding, the two countries will cooperate on creation of an "International Lunar Science Station" and plan to invite other countries to participate. The agreement was signed by Zhang Kejian, director of the China National Space Administration, and Dmitry Rogozin, the chief of Russia's space corporation, Roscosmos. The agreement was announced by Roscosmos.
Details about the project were fairly sparse, specifying only that the countries would work together to create research facilities on the surface and/or in orbit around the Moon. The goal was both to establish long-term, uncrewed facilities on the Moon and build up the capabilities for a human presence there. China has previously disclosed its ambitions to build an international lunar station at the South Pole of the Moon, beginning with robotic missions and followed by short-term human missions in the early 2030s. The country plans to establish a long-term human presence at the South Pole—which is believed to contain vast reserves of water ice... (MORE)
- - - - -
Is Putin’s Russia Fascist?: A growing number of Russian analysts, in Russia and abroad, have taken to calling Vladimir Putin’s regime “fascist.” And they don’t use the term casually or as a form of opprobrium. They mean that Putin’s Russia genuinely resembles Mussolini’s Italy or Hitler’s Germany...
https://nautil.us/issue/98/mind/comets-a...we-thought
EXCRPTS: . . . Now comets, as you may know, come from far away, and spend little time in the inner solar system. Scientists, based on decades of work, consider it to be a minor risk for one to collide with Earth. A new study, however, hints that comets pose a much greater threat than previously thought. Specifically, it’s the long-period, rather than the short-period ones, we have to look out for. [...] Long-period comets are the least likely to hit our planet because they visit the inner solar system rarely (often just once) and zip by so quickly that the Earth is a tiny target. They originate in the Oort cloud...
[...] In the new study, published in Scientific Reports, Harvard astrophysicists Amir Siraj and Avi Loeb (yes, the backer of that controversial hypothesis about aliens) add a wrinkle to this story. They calculate that about 20 percent of long-period comets that pass within Earth’s orbit pass so close to the sun that they are torn apart by tidal forces. This process creates long strands of comet fragments that vastly increase the odds of collision with the Earth.
[...] Scientists know several groups of comets that are likely tidal fragments. For example, the Kreutz group contains thousands of comets stretched along similar orbits around the sun that are thought to be the remnants of a single giant comet that disrupted a thousand or more years ago... (MORE - details)
The asteroid belt: Wreckage of a destroyed planet or something else?
https://astronomy.com/news/2021/03/the-a...thing-else
EXCERPT: Billions of years ago, our solar system was far from being a stable and organized place. Planets were still forming, throwing their neighbor’s orbits out of whack in the process. In light of all this action, some astronomers used to believe a planet that orbited our Sun between the trajectories of Mars and Jupiter was blasted into pieces and formed the asteroid belt that floats in space today.
Scientists thought that "maybe there was a planet there and it got blown to smithereens,” explains Sean Raymond, an astronomer at the Astrophysical Laboratory of Bordeaux, in France. But after researchers began to examine the patterns in iron meteorites that fell to the Earth as meteors, Raymond says, it became clear they didn’t come from one parent body.
As a result, the thinking began to shift toward the idea that the asteroid belt was full of planetesimals, or pieces of a planet that either hadn’t formed or failed to form. But the trouble with this theory is that there just isn’t enough material in the belt to create such a mass. Ceres is the single largest asteroid in the belt, roughly the size of Australia with a mass nearly half that of all the material of the belt, according to Raymond. “It’s like tiny little crumbs,” Raymond says.
Just because the asteroid belt doesn’t represent the leftovers of a former planet doesn’t mean scientists have abandoned the idea entirely. The belt might have come from parts of other planets that still exist, or be part of a planetesimal — which is like a baby planet — that never completely formed before being smashed apart. “It used to be kind of a simple story, but in recent years it’s gotten increasingly more complicated as we learn more about planet formation,” [William] Bottke says... (MORE - details)
Russia says it will work with China on a Moon base (the "because fascism & Marxism are bedfellows at a deeper level" category)
https://arstechnica.com/science/2021/03/...r-station/
INTRO: The heads of the Chinese and Russian space agencies signed an agreement on Tuesday to work together to build a "scientific" station on the Moon. Under terms of a memorandum of understanding, the two countries will cooperate on creation of an "International Lunar Science Station" and plan to invite other countries to participate. The agreement was signed by Zhang Kejian, director of the China National Space Administration, and Dmitry Rogozin, the chief of Russia's space corporation, Roscosmos. The agreement was announced by Roscosmos.
Details about the project were fairly sparse, specifying only that the countries would work together to create research facilities on the surface and/or in orbit around the Moon. The goal was both to establish long-term, uncrewed facilities on the Moon and build up the capabilities for a human presence there. China has previously disclosed its ambitions to build an international lunar station at the South Pole of the Moon, beginning with robotic missions and followed by short-term human missions in the early 2030s. The country plans to establish a long-term human presence at the South Pole—which is believed to contain vast reserves of water ice... (MORE)
- - - - -
Is Putin’s Russia Fascist?: A growing number of Russian analysts, in Russia and abroad, have taken to calling Vladimir Putin’s regime “fascist.” And they don’t use the term casually or as a form of opprobrium. They mean that Putin’s Russia genuinely resembles Mussolini’s Italy or Hitler’s Germany...