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Second Gravitational Wave event confirmed!
In article ,
Yousuf Khan writes: The first event seemed to happen quicker, while the second one seems more drawn out. I wonder if this tells us something about the masses of the two new blackholes? Specifically will the fact that it happened much slower for the second set of black holes, would that mean that they were smaller black holes than the first set from the September detection/February announcement? Yes. See item 2 in the press release at https://www.ligo.caltech.edu/news/ligo20160615 -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
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Second Gravitational Wave event confirmed!
Steve Willner wrote:
In article , Yousuf Khan writes: Attribution line, not attribution novel. The first event seemed to happen quicker, while the second one seems more drawn out. I wonder if this tells us something about the masses of the two new blackholes? Specifically will the fact that it happened much slower for the second set of black holes, would that mean that they were smaller black holes than the first set from the September detection/February announcement? Yes. See item 2 in the press release at https://www.ligo.caltech.edu/news/ligo20160615 IIUC, the event was that two black holes merged. If that is so, it cannot “happen quicker” or be “drawn out” or “happen slower”. The article says that the *signal* was *detected* earlier which would be a different fact. Second, why is it a valid conclusion that because the bodies’ orbital speeds were faster they *have to be* smaller i.e. for black holes that they have to have smaller masses? (I realize that was so in this case.) F'up2 sci.astro -- PointedEars Twitter: @PointedEars2 Please do not cc me. / Bitte keine Kopien per E-Mail. |
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Second Gravitational Wave event confirmed!
On 17/06/2016 5:22 PM, Steve Willner wrote:
In article , Yousuf Khan writes: The first event seemed to happen quicker, while the second one seems more drawn out. I wonder if this tells us something about the masses of the two new blackholes? Specifically will the fact that it happened much slower for the second set of black holes, would that mean that they were smaller black holes than the first set from the September detection/February announcement? Yes. See item 2 in the press release at https://www.ligo.caltech.edu/news/ligo20160615 Great, now I wonder how much of their energy was turned into gravity waves? In the first event, a 29 and a 36 solar mass black holes turned into 5 solar masses of gravity waves, and 60 solar mass of newly formed black hole. Going proportionally, the secondary black holes are 8 & 14, so I would guess that would result in 2 solar masses of gravity waves, and 20 solar masses of new black hole. Yousuf Khan |
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Second Gravitational Wave event confirmed!
Yousuf Khan wrote:
^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Sammy’s got a new pseudonym but no e-mail address? […] I wonder how much of their energy was turned into gravity ^^^^^^^ waves? In the first event, a 29 and a 36 solar mass black holes turned ^^^^^ into 5 solar masses of gravity waves, and 60 solar mass of newly formed ^^^^^^^^^^^^^ ^^ black hole. “In the source frame, the initial black hole masses are 36⁺⁵₋₄ M⊙ and 29⁺⁴₋₄ M⊙, and the final black hole mass is /62⁺⁴₋₄ M⊙/, with /3.0^{+0.5}_{−0.5} M⊙ c²/ radiated in /gravitational/ waves [0].” [1] (emphasis and reference mine) Going proportionally, the secondary black holes are 8 & 14, so I would guess that would result in 2 solar masses of gravity waves, and 20 solar masses of new black hole. Not quite. If you read the paper at PRL (which you can for free again, thank you LSC and VC), you will realize that naive arithmetics does not work because mass–energy is only one component of a body’s energy: “The inferred source-frame initial black hole masses are 14.2^{+8.3}_{−3.7} M⊙ and 7.5^{+2.3}_{−2.3} M⊙, and the final black hole mass is 20.8^{+6.1}_{−1.7} M⊙.” [2] F'up2 sci.physics ___________ [0] http://en.wikipedia.org/wiki/Gravity_wave vs. http://en.wikipedia.org/wiki/Gravitational_wave [1] B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration). Phys. Rev. Lett. 116, 061102. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 [2] B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration). Phys. Rev. Lett. 116, 241103. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103 -- PointedEars Twitter: @PointedEars2 Please do not cc me. / Bitte keine Kopien per E-Mail. |
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Second Gravitational Wave event confirmed!
Thomas 'PointedEars' Lahn writes:
Going proportionally, the secondary black holes are 8 & 14, so I would guess that would result in 2 solar masses of gravity waves, and 20 solar masses of new black hole. Not quite. If you read the paper at PRL (which you can for free again, thank you LSC and VC), you will realize that naive arithmetics does not work because mass–energy is only one component of a body’s energy: In the online story I read, the black hole masses were 14.2 and 7.5 solar masses and the resulting final black hole was about 20.8 solar masses, producing 0.9 solar masses of gravitational radiation. But the uncertainties in all figures was rather large. |
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Second Gravitational Wave event confirmed!
In sci.astro message , Sat, 18 Jun
2016 00:01:22, Thomas 'PointedEars' Lahn posted: Steve Willner wrote: In article , Yousuf Khan writes: Attribution line, not attribution novel. The first event seemed to happen quicker, while the second one seems more drawn out. I wonder if this tells us something about the masses of the two new blackholes? Specifically will the fact that it happened much slower for the second set of black holes, would that mean that they were smaller black holes than the first set from the September detection/February announcement? Yes. See item 2 in the press release at https://www.ligo.caltech.edu/news/ligo20160615 IIUC, the event was that two black holes merged. If that is so, it cannot “happen quicker” or be “drawn out” or “happen slower”. The article says that the *signal* was *detected* earlier which would be a different fact. Second, why is it a valid conclusion that because the bodies’ orbital speeds were faster they *have to be* smaller i.e. for black holes that they have to have smaller masses? (I realize that was so in this case.) Perhaps you should learn some physics. But learn to be human first. -- (c) John Stockton, Surrey, UK. Turnpike v6.05 MIME. Merlyn Web Site - FAQish topics, acronyms, & links. |
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Second Gravitational Wave event confirmed!
Dne 18/06/2016 v 15:49 Dr J R Stockton napsal(a):
In sci.astro message , Sat, 18 Jun 2016 00:01:22, Thomas 'PointedEars' Lahn posted: Steve Willner wrote: Yes. See item 2 in the press release at https://www.ligo.caltech.edu/news/ligo20160615 IIUC, the event was that two black holes merged. If that is so, it cannot “happen quicker” or be “drawn out” or “happen slower”. The article says that the *signal* was *detected* earlier which would be a different fact. Second, why is it a valid conclusion that because the bodies’ orbital speeds were faster they *have to be* smaller i.e. for black holes that they have to have smaller masses? (I realize that was so in this case.) Perhaps you should learn some physics. But learn to be human first. To Thomas defence, his knowledge of physics is very good, and he is right at this point. But I do not say the same about his social skills ( neither of my English ). Shorter orbital speeds = lower masses is not generally true, as there are 3 players in the games - distance, period and masses, The former 2 cannot be reduced to the speed, having different power degrees in the equation. -- Poutnik ( The Pilgrim, Der Wanderer ) Knowledge makes great men humble, but small men arrogant. |
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Second Gravitational Wave event confirmed!
In article ,
Yousuf Khan writes: Great, now I wonder how much of their energy was turned into gravity waves? I'm coming back to this late, but the answer is in the paper draft at https://dcc.ligo.org/LIGO-P1600088/main/public Table 1 shows total initial mass 21.8 Msun and final mass 20.8 Msun, but both have uncertainties of more than 1 Msun. However, the radiated energy is given as 1.0(+0.1/-0.2) Msun, so it seems reasonably well determined. By the way, the correct term for what LIGO is looking for is "gravitational waves." Ordinary water waves on a lake or ocean are examples of "gravity waves." That name distinguishes them from "pressure waves" such as sound. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
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