Scientists uncover what accelerated an interstellar comet through our solar systemhttps://edition.cnn.com/2023/03/23/world/oumuamua-interstellar-comet-scn/index.html
NASA is actively monitoring a strange anomaly in Earth's magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa.This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers.The space agency's satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.
NASA Is Tracking a Huge, Growing Anomaly in Earth's Magnetic FieldQuote NASA is actively monitoring a strange anomaly in Earth's magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa.This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers.The space agency's satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.https://www.sciencealert.com/nasa-is-tracking-a-huge-growing-anomaly-in-earths-magnetic-field
Quote from: Star One on 03/23/2023 07:05 pmNASA Is Tracking a Huge, Growing Anomaly in Earth's Magnetic FieldQuote NASA is actively monitoring a strange anomaly in Earth's magnetic field: a giant region of lower magnetic intensity in the skies above the planet, stretching out between South America and southwest Africa.This vast, developing phenomenon, called the South Atlantic Anomaly, has intrigued and concerned scientists for years, and perhaps none more so than NASA researchers.The space agency's satellites and spacecraft are particularly vulnerable to the weakened magnetic field strength within the anomaly, and the resulting exposure to charged particles from the Sun.https://www.sciencealert.com/nasa-is-tracking-a-huge-growing-anomaly-in-earths-magnetic-fieldClick-bait baloney.This makes it sound like it's some dangerous "developing phenomenon" that we should be worried about. It was discovered in 1958. NASA has been "tracking" it for 65 years.
Quote from: Star One on 03/23/2023 04:27 pmScientists uncover what accelerated an interstellar comet through our solar systemhttps://edition.cnn.com/2023/03/23/world/oumuamua-interstellar-comet-scn/index.htmlArticles about 'Oumuamua always bother me because they claim that the object "swept through the Solar system" or some such. In fact the object's velocity was low relative to the average velocity of nearby stars other than Sol. It was more or less just sitting there minding its own business. The Solar system's velocity is higher relative to nearby stars, so Sol "swept by" 'Oumuamua, not the other way around. The interaction kicked the object's velocity up.
Quote from: DanClemmensen on 03/23/2023 06:20 pmQuote from: Star One on 03/23/2023 04:27 pmScientists uncover what accelerated an interstellar comet through our solar systemhttps://edition.cnn.com/2023/03/23/world/oumuamua-interstellar-comet-scn/index.htmlArticles about 'Oumuamua always bother me because they claim that the object "swept through the Solar system" or some such. In fact the object's velocity was low relative to the average velocity of nearby stars other than Sol. It was more or less just sitting there minding its own business. The Solar system's velocity is higher relative to nearby stars, so Sol "swept by" 'Oumuamua, not the other way around. The interaction kicked the object's velocity up.While the first assertion that “Sol swept by Oumuamua “ is valid, that last statement is not correct. <snip other accelerations...>
Quote from: DanClemmensen on 03/23/2023 06:20 pmQuote from: Star One on 03/23/2023 04:27 pmScientists uncover what accelerated an interstellar comet through our solar systemhttps://edition.cnn.com/2023/03/23/world/oumuamua-interstellar-comet-scn/index.htmlArticles about 'Oumuamua always bother me because they claim that the object "swept through the Solar system" or some such. In fact the object's velocity was low relative to the average velocity of nearby stars other than Sol. It was more or less just sitting there minding its own business. The Solar system's velocity is higher relative to nearby stars, so Sol "swept by" 'Oumuamua, not the other way around. The interaction kicked the object's velocity up.While the first assertion that “Sol swept by Oumuamua “ is valid, that last statement is not correct.‘Oumuamua /I1 was observed to be accelerating away from the Sun with no observed water or ion tail as would be expected from an icy comet.(That periodic comets have a randomness to their return trajectories enabled Fred Whipple to surmise that comets were “dirty snowballs” of ice and dust, with jets of sublimating ice giving erratic pushes away from the Sun.)Citing that and the extreme shape, evidenced by huge swings in its light curve, and the trajectory that went inside the orbit of Mercury as “targeting”, Dr Avi Loeb of Harvard wrote technical papers and a bestselling book “Extraterrestrial” that posit the best explanation is a tumbling solar sail probe built by … extraterrestrials.This article posits that I1 was a regular water ice comet, albeit still interstellar, processed by starlight to have an undetectable hydrogen tail.Loeb and colleague have published a paper with physical arguments that their calculated thrust is high by a factor of three.YCMV (C=calculations)There is another paper suggesting that ‘Oumaumau is a solid hydrogen iceberg, and how that could be formed and maintained with a sublimation temperature below the temperature of the cosmic microwave background. It discussed how irregularities in the initial shape would amplify as it sublimated, like a bar of soap gets very thin towards its end.Another paper supports the idea that it is an iceberg of solid nitrogen, from which a cometary tail also would not have been observed. (This is my favorite explanation because we have in fact seen icebergs of solid nitrogen, … on Pluto!)Dr Karen Meech, an authority on comets, has said (published?) that it could still have been an icy comet whose tail was just below the threshold of detection for the few observations that were made before it flew back into the interstellar darkness.(Apologies for not hypertext linking all those references but that would take me days.)Edit: Duh! Book title!