Comment A little long but good (Score 1) 2
Long time, no see! Totally agree with this assessment!
Submission + - Another large Black hole in "our" Galaxy (arxiv.org)
RockDoctor writes: A recent paper on ArXiv reports a novel idea about the central regions of "our" galaxy.
Remember the hoopla a few years ago about radio-astronomical observations producing an "image" of our central black hole — or rather, an image of the accretion disc around the black hole — long designated by astronomers as "Sagittarius A*" (or SGR-A*)? If you remember the image published then, one thing should be striking — it's not very symmetrical. If you think about viewing a spinning object, then you'd expect to see something with a "mirror" symmetry plane where we would see the rotation axis (if someone had marked it). If anything, that published image has three bright spots on a fainter ring. And the spots are not even approximately the same brightness.
This paper suggests that the image we see is the result of the light (radio waves) from SGR-A* being "lensed" by another black hole, near (but not quite on) the line of sight between SGR-A* and us. By various modelling approaches, they then refine this idea to a "best-fit" of a black hole with mass around 1000 times the Sun, orbiting between the distance of the closest-observed star to SGR-A* ("S2" — most imaginative name, ever!), and around 10 times that distance. That's far enough to make a strong interaction with "S2" unlikely within the lifetime of S2 before it's accretion onto SGR-A*.)
The region around SGR-A* is crowded. Within 25 parsecs (~80 light years, the distance to Regulus [in the constellation Leo] or Merak [in the Great Bear]) there is around 4 times more mass in several millions of "normal" stars than in the SGR-A* black hole. Finding a large (not "super massive") black hole in such a concentration of matter shouldn't surprise anyone.
This proposed black hole is larger than anything which has been detected by gravitational waves (yet) ; but not immensely larger — only a factor of 15 or so. (The authors also anticipate the "what about these big black holes spiralling together?" question : quote "and the amplitude of gravitational waves generated by the binary black holes is negligible.")
Being so close to SGR-A*, the proposed black hole is likely to be moving rapidly across our line of sight. At the distance of "S2" it's orbital period would be around 26 years (but the "new" black hole is probably further out than than that). Which might be an explanation for some of the variability and "flickering" reported for SGR-A* ever since it's discovery.
As always, more observations are needed. Which, for SGR-A* are frequently being taken, so improving (or ruling out) this explanation should happen fairly quickly. But it's a very interesting, and fun, idea.
Remember the hoopla a few years ago about radio-astronomical observations producing an "image" of our central black hole — or rather, an image of the accretion disc around the black hole — long designated by astronomers as "Sagittarius A*" (or SGR-A*)? If you remember the image published then, one thing should be striking — it's not very symmetrical. If you think about viewing a spinning object, then you'd expect to see something with a "mirror" symmetry plane where we would see the rotation axis (if someone had marked it). If anything, that published image has three bright spots on a fainter ring. And the spots are not even approximately the same brightness.
This paper suggests that the image we see is the result of the light (radio waves) from SGR-A* being "lensed" by another black hole, near (but not quite on) the line of sight between SGR-A* and us. By various modelling approaches, they then refine this idea to a "best-fit" of a black hole with mass around 1000 times the Sun, orbiting between the distance of the closest-observed star to SGR-A* ("S2" — most imaginative name, ever!), and around 10 times that distance. That's far enough to make a strong interaction with "S2" unlikely within the lifetime of S2 before it's accretion onto SGR-A*.)
The region around SGR-A* is crowded. Within 25 parsecs (~80 light years, the distance to Regulus [in the constellation Leo] or Merak [in the Great Bear]) there is around 4 times more mass in several millions of "normal" stars than in the SGR-A* black hole. Finding a large (not "super massive") black hole in such a concentration of matter shouldn't surprise anyone.
This proposed black hole is larger than anything which has been detected by gravitational waves (yet) ; but not immensely larger — only a factor of 15 or so. (The authors also anticipate the "what about these big black holes spiralling together?" question : quote "and the amplitude of gravitational waves generated by the binary black holes is negligible.")
Being so close to SGR-A*, the proposed black hole is likely to be moving rapidly across our line of sight. At the distance of "S2" it's orbital period would be around 26 years (but the "new" black hole is probably further out than than that). Which might be an explanation for some of the variability and "flickering" reported for SGR-A* ever since it's discovery.
As always, more observations are needed. Which, for SGR-A* are frequently being taken, so improving (or ruling out) this explanation should happen fairly quickly. But it's a very interesting, and fun, idea.
Submission + - Surado, formerly Slashdot Japan, is closing at the end of the month. (srad.jp) 1
AmiMoJo writes: Slashdot Japan was launched on May 28, 2001. On 2025/03/31, it will finally close. Since starting the site separated from the main Slashdot one, and eventually rebranded as "Surado", which was it's Japanese nickname.
Last year the site stopped posting new stories, and was subsequently unable to find a buyer. In a final story announcing the end, many users expressed their sadness and gratitude for all the years of service.
Last year the site stopped posting new stories, and was subsequently unable to find a buyer. In a final story announcing the end, many users expressed their sadness and gratitude for all the years of service.
Comment Re:way 525 that bitcoin can not be used for day to (Score 1) 51
You need satellite or dialup or StarLink or whatever and you have your access,
And no, they did nothing to the global network. China shutting down 50% of miners back in May did nothing. Kazakhstan shutting off 12% sure as heck didn’t do anything.
Comment Re:Access to wallet (Score 1) 37
Considering he used Coinbase, probably.
Comment Re:Web3 is speculatively stupid. (Score 1) 90
DNS decentralized? Right up they yank your domain off the net. IP assignment? Lol!
Comment Re:So if Jack doesn't like it, then it's good... (Score 1) 90
No, it’s the exact opposite. He doesn’t like it because it’s centralized and under control of media and tech elites.
Comment Re:Surprised this didn’t happen sooner (Score -1, Offtopic) 44
Individual mining might be making a comeback. Compass Mining will host an ASIC for you, at a location of your choosing:
Stratum2 has been released and should make the pools less powerful:
https://braiins.com/stratum-v2
Blockstream is also working on home-friendly mining hardware. You see, it’s not all lost.
Comment Re: Maybe they should ask questions about this? (Score 1) 50
What, 4-5 month, cherry-picked? That’s ridiculous. Why did you even bother? Zoom out to anything more than a two years and there’s no correlation. Anyone who’s seen the charts knows that.
Comment On Ethereum (Score 1) 17
A long Twitter thread on Ethereum, mostly centred on the PoS switch:
https://twitter.com/hugohanoi/...
You could say a lot more.
Comment Re:Never more than 21million Bitcoins (Score 1) 56
A clear majority of miners wanted a block size increase in 2017, didn’t happen anyway. Miners just don’t control bitcoin. I can recommend this book that describes those events really well:
https://www.amazon.com/Blocksi...
Also, you fall for the next “hotness” if you don’t understand bitcoin is decentralized, immutable and censorship resistant. None of the other ones satisfy a single of those characteristics.
Comment Re: Maybe they should ask questions about this? (Score 1) 50
You got a chart to go with that assertion? No, I didnâ(TM)t think so.
Comment Re:They pump... and dump... (Score 1) 115
This perfectly serious message got modded as Troll. This type of censorship is why I stopped patronizing Slashdot years ago.
Comment Re:No for 2 reasons (Score 1) 54
SEC just approved a bitcoin ETF. Another couple on the way. There are 3 ETFs on TSX (Toronto) since the spring.
Comment Re:Probably Not (Score 1) 54
Seems the market disagrees with your ridiculous 2015 narrative. Bcash was as high as 0.3 bitcoin in 2017, down to 0.01 now and still sliding. Is it still in the top 20 coins? Probably not for long.
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