A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Astronomy Misc
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Second Gravitational Wave event confirmed!



 
 
Thread Tools Display Modes
  #1  
Old June 17th 16, 10:22 PM posted to sci.physics,sci.astro
Steve Willner
external usenet poster
 
Posts: 1,172
Default 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
  #2  
Old June 17th 16, 11:01 PM posted to sci.physics,sci.astro
Thomas 'PointedEars' Lahn
external usenet poster
 
Posts: 76
Default 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.
  #3  
Old June 18th 16, 01:45 AM posted to sci.physics,sci.astro
Yousuf Khan[_2_]
external usenet poster
 
Posts: 1,692
Default 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

  #4  
Old June 18th 16, 04:12 AM posted to sci.physics,sci.astro
Thomas 'PointedEars' Lahn
external usenet poster
 
Posts: 76
Default 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.
  #5  
Old June 18th 16, 05:59 AM posted to sci.physics,sci.astro
Michael Moroney
external usenet poster
 
Posts: 124
Default 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.
  #6  
Old June 18th 16, 02:49 PM posted to sci.physics,sci.astro
Dr J R Stockton[_196_]
external usenet poster
 
Posts: 32
Default 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.


  #7  
Old June 19th 16, 06:47 AM posted to sci.physics,sci.astro
Poutnik[_5_]
external usenet poster
 
Posts: 68
Default 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.
  #8  
Old June 30th 16, 07:40 PM posted to sci.physics,sci.astro
Steve Willner
external usenet poster
 
Posts: 1,172
Default 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
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Second Gravitational Wave likely detected Yousuf Khan[_2_] Astronomy Misc 1 April 15th 16 01:21 AM
Gravitational wave data... dlzc Astronomy Misc 2 February 17th 16 04:57 PM
1908 Tunguska Event confirmed as comet Thad Floryan Amateur Astronomy 0 July 22nd 09 07:49 AM
A convenient Gravitational Wave Detector? Robert Karl Stonjek Astronomy Misc 7 January 22nd 08 11:46 PM
Article: Gravitational Wave Background Robert Karl Stonjek Astronomy Misc 10 February 7th 07 01:09 PM


All times are GMT +1. The time now is 05:02 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright 2004-2024 SpaceBanter.com.
The comments are property of their posters.