tkdguy Posted June 26, 2018 Author Report Share Posted June 26, 2018 Is someone rolling a d10 in space? Check out this color-enhanced photo of Jupiter! Blue sand dune on Mars? Strawberry Moon, and Saturn in opposition pinecone 1 Quote Link to comment Share on other sites More sharing options...
Old Man Posted June 27, 2018 Report Share Posted June 27, 2018 Japanese launch robot invasion of alien world Quote Link to comment Share on other sites More sharing options...
tkdguy Posted June 27, 2018 Author Report Share Posted June 27, 2018 15 minutes ago, Old Man said: Japanese launch robot invasion of alien world Strange. Japan usually uses its robots to defend Earth from alien invaders, not the other way round. What? Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 27, 2018 Report Share Posted June 27, 2018 Denizens of the asteroid might have their own Giant Robot and Johnny Sokko.... Quote Link to comment Share on other sites More sharing options...
Old Man Posted June 28, 2018 Report Share Posted June 28, 2018 Interestingly, several Japanese capital warships were anchored right outside Pearl Harbor yesterday. Coincidence? Quote Link to comment Share on other sites More sharing options...
tkdguy Posted June 28, 2018 Author Report Share Posted June 28, 2018 Organic molecules found in Enceladus' plumes Quote Link to comment Share on other sites More sharing options...
Lord Liaden Posted June 28, 2018 Report Share Posted June 28, 2018 We continue to focus on looking for other life like our own. I still bet my money on methane-breathers in the gas giants. ? Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted June 28, 2018 Report Share Posted June 28, 2018 Mine's on the Galilean ice moons. Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 29, 2018 Report Share Posted June 29, 2018 Fairly strong circumstantial evidence published in Nature this week that 'Oumuamua was a cometary object, in that its trajectory shows some nongravitational accelerations which are consistent with the kind of outgassing that happens to comets in a perihelion passage. In effect, the ices inside the body heat up due to solar radiation, sublime, and the gas release acts like a very weak and poorly directed rocket. This result comes from fitting an orbit to the entirety of its measured trajectory, and looking for systematic deviance in the observed motion. Not a surprise, considering what was measured during its pass: the colors and reflectance spectrum were close to that of inactive comets and similar asteroids in the Solar System. Other thing in the latest Nature is an analysis of some meteorites of martian origin; the upshot is that the crust of Mars seems to have become stable as much as a hundred million years before Earth's did, within 20 million years of the formation of the Solar System. That also is not a surprise, though it's a really short time for an astronomical process. Lawnmower Boy and DShomshak 2 Quote Link to comment Share on other sites More sharing options...
DShomshak Posted July 8, 2018 Report Share Posted July 8, 2018 Watch a Baby Exoplanet Being Born - Scientific American Quote Link to comment Share on other sites More sharing options...
archer Posted July 8, 2018 Report Share Posted July 8, 2018 On 6/28/2018 at 7:06 AM, Lord Liaden said: We continue to focus on looking for other life like our own. I still bet my money on methane-breathers in the gas giants. ? No jokes about flatulence during gaming sessions making the aliens feel at home? The community has really dropped the ball on this one. Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted July 8, 2018 Report Share Posted July 8, 2018 Methane is rather rare as a component of flatus. Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 9, 2018 Report Share Posted July 9, 2018 For humans. Ruminants are something else. Quote Link to comment Share on other sites More sharing options...
DShomshak Posted July 13, 2018 Report Share Posted July 13, 2018 Heard on the radio yesterday: Astronomers at the Ice Cube neutrino observatory at the South Pole have tracked high-energy neutrinos back to a "blazar" galaxy 4 billion light-years away, in the direction of Orion. Dean Shomshak Quote Link to comment Share on other sites More sharing options...
tkdguy Posted July 18, 2018 Author Report Share Posted July 18, 2018 12 newly-discovered moons orbiting Jupiter Waves of plasma flow between Saturn & Enceladus Quote Link to comment Share on other sites More sharing options...
DShomshak Posted July 18, 2018 Report Share Posted July 18, 2018 19 hours ago, tkdguy said: Waves of plasma flow between Saturn & Enceladus It... it speaks to me. Ia Tsathoggua! I hear and obey! Dean Shomshak tkdguy 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 18, 2018 Report Share Posted July 18, 2018 On July 13, 2018 at 3:01 PM, DShomshak said: Heard on the radio yesterday: Astronomers at the Ice Cube neutrino observatory at the South Pole have tracked high-energy neutrinos back to a "blazar" galaxy 4 billion light-years away, in the direction of Orion. Dean Shomshak I had time to read up on this over the last few days. Besides the neutrino detections, there is gamma-ray data and optical data on the emitting galaxy. That one (TXS 0506+056) on the basis of its gamma-ray emission was already on the list of fifty most luminous blazars known. A "blazar" is a galaxy with a supermassive black hole in it, like a quasar. "Supermassive" means around or upwards of a billion solar masses. Of the quasars and other active galaxies, some are known to have jets of stuff coming out of the region around the black hole; the matter in the jets is moving at nearly light speed. (M 87 is one such; it's not a full quasar, but it is close enough to see reasonably well, and the image in the linked page shows the jet coming out of the center of the galaxy. 3C 273 is the nearest quasar to us, and its jet also can be seen in pictures pretty easily.) In a blazar, the jet is directed just about directly at us. That makes it rather difficult to see anything about the galaxy other than the jet itself; there's a lot of exceedingly hot gas moving at near-light speed right at us. (The name blazar is derived from "BL Lac", the prototype object of this kind.) The same astrophysical processes that make gamma rays can also make very high energy neutrinos. Seeing both, in time sequences where the correlation between neutrino arrival and higher gamma-ray flux, definitely validates the overall result. L. Marcus, DShomshak and tkdguy 2 1 Quote Link to comment Share on other sites More sharing options...
dmjalund Posted July 19, 2018 Report Share Posted July 19, 2018 22 hours ago, tkdguy said: 12 newly-discovered moons orbiting Jupiter Lawnmower Boy, L. Marcus and tkdguy 2 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 19, 2018 Report Share Posted July 19, 2018 I went looking for more details on the new Jovian moons. There does not seem to be a real technical publication of this yet; the most definitive source I have found so far is the root institution's press release here. tkdguy 1 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted July 19, 2018 Author Report Share Posted July 19, 2018 "I'm gonna eat you!" Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 20, 2018 Report Share Posted July 20, 2018 IF there are complete, or largely complete, Dyson spheres out there, the results from the ongoing Gaia astrometry mission, coupled with other observations we can make, has a chance of recognizing them. (Astrometry = the discipline of highly precise measurements of star positions and motions in the sky.) Source (behind subscriber wall) Incomprehensible abstract behind spoiler tags. A star enshrouded in a Dyson sphere with a high covering fraction may manifest itself as an optically subluminous object with a spectrophotometric distance estimate significantly in excess of its parallax distance. Using this criterion, the Gaia mission will in coming years allow for Dyson sphere searches that are complementary to searches based on waste-heat signatures at infrared wavelengths. A limited search of this type is also possible at the current time, by combining Gaia parallax distances with spectrophotometric distances from ground-based surveys. Here, we discuss the merits and shortcomings of this technique and carry out a limited search for Dyson sphere candidates in the sample of stars common to Gaia Data Release 1 and Radial Velocity Experiment (RAVE) Data Release 5. We find that a small fraction of stars indeed display distance discrepancies of the type expected for nearly complete Dyson spheres. To shed light on the properties of objects in this outlier population, we present follow-up high-resolution spectroscopy for one of these stars, the late F-type dwarf TYC 6111-1162-1. The spectrophotometric distance of this object is about twice that derived from its Gaia parallax, and there is no detectable infrared excess. While our analysis largely confirms the stellar parameters and the spectrophotometric distance inferred by RAVE, a plausible explanation for the discrepant distance estimates of this object is that the astrometric solution has been compromised by an unseen binary companion, possibly a rather massive white dwarf (≈1 M ⊙). This scenario can be further tested through upcoming Gaia data releases. In effect, they tried their method for one star that meets their criteria. Probably no Dyson sphere, but there is probably something else in the system (something not interesting SETI-wise, like a white dwarf companion) messing with the star. Oh well. OTOH, if there are Dyson sphere civilizations in our part of the Galaxy, this is a plausible way of detecting them in the next decade or so. L. Marcus, DShomshak, tkdguy and 1 other 4 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted July 27, 2018 Author Report Share Posted July 27, 2018 Radar evidence of subglacial liquid water on Mars Lawnmower Boy, DShomshak and Cancer 3 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted August 2, 2018 Author Report Share Posted August 2, 2018 Supermassive black hole in Sagittarius A* Ross 128b Quote Link to comment Share on other sites More sharing options...
DShomshak Posted August 3, 2018 Report Share Posted August 3, 2018 The August, 2018 issue of Scientific American has an article on, "Is Dark Matter Real?" The authors point out various flaws in the theory -- notably including the failure to otherwise detect any of the hypothesized particles it's made of, which the LHC should now be producing if the theories that predict them were correct. The authors prefer Modified Gravity theories. They admit these theories also have problems, and some have been killed by the recent dual observation of colliding neutron stars, but they suggest that the failures of Dark Matter theory should set astrophysicists looking harder for alternatives. (including one really wild alternative in which the phenomena ascribed to the gravity of dark matter might not be due to gravity at all.) ADDENDUM: I forgot the most important part! The three theories -- particle dark matter, modified gravity and superfluid dark matter -- make different predictions for low surface brightness galaxies and the very early universe. Upcoming telescopes such as the James Webb and Large Synoptic Survey Telescope should be able to make observations that confirm or deny. (Or, perhaps, upend everyone's theories and send theorists back to square one.) Dean Shomshak RDU Neil 1 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted August 13, 2018 Author Report Share Posted August 13, 2018 US Space Force to become the sixth military branch by 2020 Parker Solar Probe launched Quote Link to comment Share on other sites More sharing options...
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