tkdguy Posted May 2, 2020 Author Report Share Posted May 2, 2020 Quote Link to comment Share on other sites More sharing options...
Cancer Posted May 18, 2020 Report Share Posted May 18, 2020 Fomalhaut b seems to have faded away DShomshak 1 Quote Link to comment Share on other sites More sharing options...
DShomshak Posted May 22, 2020 Report Share Posted May 22, 2020 Heard on the BBC yesterday: the Paris Observatory reports that, using the Very Large Telescope, theyhave observed evidence of a protoplanet forming. Not the protoplanet itself, but a distinctive S-shaped kink in the dust cloud around a star. (I think they said AB Aurigae.) Dean Shomshak L. Marcus and tkdguy 2 Quote Link to comment Share on other sites More sharing options...
Zeropoint Posted May 24, 2020 Report Share Posted May 24, 2020 We've known that this is how planets form for some time now, but it's still awesome to finally have pictures of it! tkdguy 1 Quote Link to comment Share on other sites More sharing options...
Michael Hopcroft Posted May 25, 2020 Report Share Posted May 25, 2020 On 5/18/2020 at 7:52 AM, Cancer said: Fomalhaut b seems to have faded away This sort of thing is why interstellar "generation ships" might not be a good idea. Even with the best technology on offer, we can only see what happened in the Fomalhaut system 25 years ago. As this observation shows, a lot can change in that time. If we have launched an expedition to Fomalhaut B two months ago, when they finally arrive in 200 years they will find no trace that a planet was even there (because the new evidence suggested it was never there in the first place) and then what would they do? This makes manned interstellar expeditions so risky that few countries/corporations/collectives would be confident enough or mad enough to undertake them. Quote Link to comment Share on other sites More sharing options...
Tom Cowan Posted May 27, 2020 Report Share Posted May 27, 2020 Quote Link to comment Share on other sites More sharing options...
assault Posted May 28, 2020 Report Share Posted May 28, 2020 It was behind the couch.Astronomers find 'missing matter', solving decades-long mystery of outer space OK, so since this is a media report, not a scientific report, errors in the story are to be expected. Quote Link to comment Share on other sites More sharing options...
tkdguy Posted May 30, 2020 Author Report Share Posted May 30, 2020 The NASA manned mission has just launched. This is the first time in years we've gone to space without hitching a ride from the Russians. Tom Cowan and Beast 1 1 Quote Link to comment Share on other sites More sharing options...
dmjalund Posted May 30, 2020 Report Share Posted May 30, 2020 43 minutes ago, tkdguy said: The NASA manned mission has just launched. This is the first time in years we've gone to space without hitching a ride from the Russians. we can out away our electronic thumb now tkdguy 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 10, 2020 Report Share Posted June 10, 2020 Interesting little paper (the abstract is here, paper is almost certainly behind the paywall) suggesting that that the first interstellar asteroid, 1I/'Oumuamua, included a significant proportion of H2 ice. The object showed no comet-like gas emission while it passed through the inner Solar System a couple of years ago, and "comet-like" means no CO2, no water vapor, no methane, etc; it also had a weird shape (something like 8 times as long as it was wide). If this hydrogen-ice idea is right, then the object is probably about 100 million years old (not long on an astronomical time scale). DShomshak 1 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted June 11, 2020 Author Report Share Posted June 11, 2020 Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 15, 2020 Report Share Posted June 15, 2020 The parallax of Proxima Cen is obvious when seen from 46 AU out The image at the top of the linked page is different from, but like, the old "blink comparator" experience when looking at two photographic plates trying to see things that move ... which is how Clyde Tombaugh found Pluto 90 years ago. DShomshak and tkdguy 2 Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 24, 2020 Report Share Posted June 24, 2020 This is going to be a fiercely thick read, but ... Gravity wave detection of merger of 23 solar mass black hole and 2.6 solar mass compact object (That's an "open access" Astrophysical Journal Letters paper.) Most interesting about this are two things. First is the mass ratio, where the more massive object is about 9 times the mass of the lower mass one; this is the biggest difference in pre-merger masses yet seen. The other interesting aspect is that "compact object" label on the low-mass component: 2.6 solar masses is close to the theoretical maximum mass of a neutron star (NS); so close to that limit that heavy investigation was done to see if a NS is permitted in the event solution. (The equation of state of nuclear matter is poorly known in the relevant regime, and it is a big part of what sets the upper limit to neutron star mass; consequently, this result is of considerable interest to the nuclear physics community as well.) The gravity-wave solution favors the lower-mass precursor being a black hole (BH) rather than a NS, but does not rule out the NS possibility. There was no electromagnetic flash accompanying the event (which there was for GW180817, the two-merging-neutron-stars event where the r-process made the front page of newspapers about 2.5 years back); this again favors the BH idea, but does not rule out the NS possibility either. DShomshak 1 Quote Link to comment Share on other sites More sharing options...
DShomshak Posted June 25, 2020 Report Share Posted June 25, 2020 I heard about this on BBC World Service today. I hoped someone would post something with more information. The astronomer interviewed likewise drew attention to the unusual mass of the smaller object. She said that it was massive enough that it being a neutron star was iffy, but OTOH it's smaller than any other black hole astronomers have found; it's been thought that 5 solar masses was about the lower limit for black holes. But okay, maybe not. Or... it's something else, that nobody's observed before. (I've read speculations about quark stars.) Dean Shomshak Quote Link to comment Share on other sites More sharing options...
DShomshak Posted June 25, 2020 Report Share Posted June 25, 2020 I heard about this on BBC World Service today. I hoped someone would post something with more information. The astronomer interviewed likewise drew attention to the unusual mass of the smaller object. She said that it was massive enough that it being a neutron star was iffy, but OTOH it's smaller than any other black hole astronomers have found; it's been thought that 5 solar masses was about the lower limit for black holes. But okay, maybe not. Or... it's something else, that nobody's observed before. (I've read speculations about quark stars.) Dean Shomshak Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 26, 2020 Report Share Posted June 26, 2020 They are toward the bottom of the paper, but there is some discussion of the more exotic sorts of compact object. I have the impression that little enough is known about those that this discovery doesn't say much about those ideas (i.e., the models are too skimpy for them to be ruled in or out by these observations). It would have been much more interesting if both BH and NS had been excluded by the gravity wave solution, but that did not turn out to be the case. The modest-mass black hole is the leading candidate, and the puzzle of how you get a 2.6 solar mass black hole is now on everyone's plate. DShomshak 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted June 26, 2020 Report Share Posted June 26, 2020 Need adventure ideas? NASA's "Galaxy of Horrors" poster series ... intended as science public outreach, but .... tkdguy 1 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted June 26, 2020 Author Report Share Posted June 26, 2020 3 hours ago, Cancer said: Need adventure ideas? NASA's "Galaxy of Horrors" poster series ... intended as science public outreach, but .... Now I want to run a Pulp SF campaign! Quote Link to comment Share on other sites More sharing options...
Lord Liaden Posted June 26, 2020 Report Share Posted June 26, 2020 2 hours ago, tkdguy said: Now I want to run a Pulp SF campaign! tkdguy 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 9, 2020 Report Share Posted July 9, 2020 Is Betelgeuse a post-merger object? tkdguy 1 Quote Link to comment Share on other sites More sharing options...
dmjalund Posted July 10, 2020 Report Share Posted July 10, 2020 11 hours ago, Cancer said: Is Betelgeuse a post-merger object? Aren't we all? Lord Liaden, Ninja-Bear and tkdguy 1 2 Quote Link to comment Share on other sites More sharing options...
tkdguy Posted July 19, 2020 Author Report Share Posted July 19, 2020 Quote Link to comment Share on other sites More sharing options...
Scott Ruggels Posted July 23, 2020 Report Share Posted July 23, 2020 https://www.space.com/spacex-falcon-9-rocket-payload-fairing-catch-success.html tkdguy 1 Quote Link to comment Share on other sites More sharing options...
Cancer Posted July 24, 2020 Report Share Posted July 24, 2020 More suggestions about an ancient ocean on Mars DShomshak and tkdguy 2 Quote Link to comment Share on other sites More sharing options...
DShomshak Posted July 25, 2020 Report Share Posted July 25, 2020 Last week I saw Comet NEOWISE on a fortunately clear night. Has anyone else? Dean Shomshak Quote Link to comment Share on other sites More sharing options...
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