APOD: Black Holes of Known Mass (2017 Jun 02)

Comments and questions about the APOD on the main view screen.
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neufer
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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by neufer » Fri Jun 02, 2017 5:03 pm

douglas wrote:
Would any human-protective technology powerful enough to resist tides also make it impossible to use a wormhole?
https://en.wikipedia.org/wiki/King_Canute_and_the_waves wrote:
<<King Canute set his throne by the sea shore and commanded the incoming tide to halt and not wet his feet and robes. Yet "continuing to rise as usual [the tide] dashed over his feet and legs without respect to his royal person. Then the king leapt backwards, saying: 'Let all men know how empty and worthless is the power of kings, for there is none worthy of the name, but He whom heaven, earth, and sea obey by eternal laws.'">>
https://en.wikipedia.org/wiki/United_States_withdrawal_from_the_Paris_Agreement wrote:
<<On June 1, 2017, United States President Donald Trump announced that the U.S. would cease all participation with the 2015 Paris Agreement on climate change mitigation. In accordance with Article 28 of the Paris Agreement, the earliest possible effective withdrawal date by the United States cannot be before 4 November 2020, four years after the Agreement came into effect in the United States. Russian President Vladimir Putin praised the withdrawal and stated that the world should "not worry [and] be happy".>>
Art Neuendorffer

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by FLPhotoCatcher » Fri Jun 02, 2017 6:42 pm

Awesome detector!

I'm guessing gravity waves can not escape black holes, since supposedly nothing can. But what happens to gravity waves inside, say, a super-massive black hole that are being created by an orbiting smaller black hole? If gravity waves can not escape the large black hole, then the smaller black hole's gravity effects on the overall shape of the event horizon SHOULD DISAPPEAR INSTANTLY AFTER IT PASSES THE EVENT HORIZON. This does not seem correct. Can G waves even be created inside a black hole?

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by chuckster » Fri Jun 02, 2017 7:51 pm

Ann wrote:
Case wrote:
Boomer12k wrote:So.... can we "surf" to Alpha Centauri on one?
Math homework problem: how close does a black hole merger have to be, to create a wave strong enough that a space ship from Earth can ride it to the next star? As the wave is directional, how much steering is possible? How do we get off the wave at our destination?
Reminds me of the age-old question: How do you get off at the right destination if you dive head first into a black hole in the hopes of finding a wormhole teleporter?

And how do you avoid getting spaghettified or turned into a seriously tenderized slab of meat if you get really close and personal with the black hole itself, or if you hitch a ride on the incredibly powerful gravitational waves generated by a really nearby black hole merger?

Ann
According to Stanislaw Lem, one product of black hole gravity waves that can be taken advantage of for interstellar journeys is time running backwards within them. With various other forms of propulsion, you achieve a relativistic velocity towards a destination near to a local black hole that you then 'ping' with a large "sidereal" gravity bomb that gets the black hole ringing back and forth between a cigar shape and a pancake shape for a second or two, creating extra-powerful gravity waves with "retrochronal toroids" within them. The ship had racked up unacceptable amounts of time dilation getting there, but entering the toroids allows it to turn back its clock, and return to Earth a few years subsequent to its departure.

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by neufer » Fri Jun 02, 2017 8:38 pm

FLPhotoCatcher wrote:
I'm guessing gravity waves can not escape black holes, since supposedly nothing can. But what happens to gravity waves inside, say, a super-massive black hole that are being created by an orbiting smaller black hole? If gravity waves can not escape the large black hole, then the smaller black hole's gravity effects on the overall shape of the event horizon SHOULD DISAPPEAR INSTANTLY AFTER IT PASSES THE EVENT HORIZON. This does not seem correct. Can G waves even be created inside a black hole?
Photons, gravitons and all other real particles with trajectories into the event horizon never return and augment the mass of the black hole.

Virtual particles with trajectories into the event horizon also never return but they reduce the mass of the black hole.
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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by distefanom » Fri Jun 02, 2017 10:03 pm

Chris Peterson wrote:
distefanom wrote:I think in the space around us (i.e. our own galaxy), should be way more smaller black holes, gliding around around and (maybe) way more often,that gigantic solar masses collide to form black holes, so one should expect a "background noise" way higher than the one detected?
LIGO is only sensitive to the inspiral of medium mass black holes. It cannot detect individual black holes of any mass, so any that might be around us would have no effect (and solar mass black holes are gravitationally no different than stars, in any case).
2) If it ìs true that Several times the sun size black holes can be detected so far away in space & time... How we can be sure that the "ringing" LIGO detects is due to this kind of mass collision?
The complex details of the gravitational wave waveform recorded by LIGO (that is, the time-dependent change in both amplitude and frequency) are exactly described by General Relativity. That's extremely strong evidence that we're observing black hole inspirals (and there are no alternative explanations at all).
Many Thanks, Chris, for your kind explanation! :D

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by FLPhotoCatcher » Sat Jun 03, 2017 3:06 am

neufer wrote:
FLPhotoCatcher wrote:
I'm guessing gravity waves can not escape black holes, since supposedly nothing can. But what happens to gravity waves inside, say, a super-massive black hole that are being created by an orbiting smaller black hole? If gravity waves can not escape the large black hole, then the smaller black hole's gravity effects on the overall shape of the event horizon SHOULD DISAPPEAR INSTANTLY AFTER IT PASSES THE EVENT HORIZON. This does not seem correct. Can G waves even be created inside a black hole?
Photons, gravitons and all other real particles with trajectories into the event horizon never return and augment the mass of the black hole.

Virtual particles with trajectories into the event horizon also never return but they reduce the mass of the black hole.
Yes, but If a small black hole orbits just inside the event horizon of a super-massive black hole, does it 'warp' the event horizon of the larger black hole?

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by Chris Peterson » Sat Jun 03, 2017 3:49 am

FLPhotoCatcher wrote:
neufer wrote:
FLPhotoCatcher wrote:
I'm guessing gravity waves can not escape black holes, since supposedly nothing can. But what happens to gravity waves inside, say, a super-massive black hole that are being created by an orbiting smaller black hole? If gravity waves can not escape the large black hole, then the smaller black hole's gravity effects on the overall shape of the event horizon SHOULD DISAPPEAR INSTANTLY AFTER IT PASSES THE EVENT HORIZON. This does not seem correct. Can G waves even be created inside a black hole?
Photons, gravitons and all other real particles with trajectories into the event horizon never return and augment the mass of the black hole.

Virtual particles with trajectories into the event horizon also never return but they reduce the mass of the black hole.
Yes, but If a small black hole orbits just inside the event horizon of a super-massive black hole, does it 'warp' the event horizon of the larger black hole?
A body can't orbit inside the event horizon of a black hole. The closest possible orbit you can have is 1.5 times the radius of the event horizon. Inside that the orbital velocity exceeds the speed of light. Once a body crosses the event horizon, it can only fall into the central singularity (technically, the radial dimension inside the event horizon is time-like, not space-like.

I believe the shape of the event horizon for a non-rotating black hole can be briefly perturbed from spherical (or oblate spherical for a rotating black hole) by material falling through it, but no information is being conveyed from the inside to the outside. The perturbation is external.
Chris

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by FLPhotoCatcher » Sat Jun 03, 2017 4:44 am

Chris Peterson wrote:
FLPhotoCatcher wrote:
neufer wrote: Photons, gravitons and all other real particles with trajectories into the event horizon never return and augment the mass of the black hole.

Virtual particles with trajectories into the event horizon also never return but they reduce the mass of the black hole.
Yes, but If a small black hole orbits just inside the event horizon of a super-massive black hole, does it 'warp' the event horizon of the larger black hole?
A body can't orbit inside the event horizon of a black hole. The closest possible orbit you can have is 1.5 times the radius of the event horizon. Inside that the orbital velocity exceeds the speed of light. Once a body crosses the event horizon, it can only fall into the central singularity (technically, the radial dimension inside the event horizon is time-like, not space-like.

I believe the shape of the event horizon for a non-rotating black hole can be briefly perturbed from spherical (or oblate spherical for a rotating black hole) by material falling through it, but no information is being conveyed from the inside to the outside. The perturbation is external.
Interesting. Thanks Chris.

douglas

Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by douglas » Sat Jun 03, 2017 1:24 pm

chuckster wrote:
According to Stanislaw Lem, one product of black hole gravity waves that can be taken advantage of for interstellar journeys is time running backwards within them. With various other forms of propulsion, you achieve a relativistic velocity towards a destination near to a local black hole that you then 'ping' with a large "sidereal" gravity bomb that gets the black hole ringing back and forth between a cigar shape and a pancake shape for a second or two, creating extra-powerful gravity waves with "retrochronal toroids" within them. The ship [of Truly God-like Energies] had racked up unacceptable amounts of time dilation getting there, but entering the toroids allows it to turn back its clock, and return to Earth a few years subsequent to its departure.
fixed that for 'ya :)

Also wondering how Stan determines "unacceptable amounts of time dilation", and of course, how subtle is a technology that "bombs" a black hole? :)

douglas

Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by douglas » Sat Jun 03, 2017 1:59 pm

FLPhotoCatcher wrote:
Chris Peterson wrote:
FLPhotoCatcher wrote: Yes, but If a small black hole orbits just inside the event horizon of a super-massive black hole, does it 'warp' the event horizon of the larger black hole?
A body can't orbit inside the event horizon of a black hole. The closest possible orbit you can have is 1.5 times the radius of the event horizon. Inside that the orbital velocity exceeds the speed of light. Once a body crosses the event horizon, it can only fall into the central singularity (technically, the radial dimension inside the event horizon is time-like, not space-like.

I believe the shape of the event horizon for a non-rotating black hole can be briefly perturbed from spherical (or oblate spherical for a rotating black hole) by material falling through it, but no information is being conveyed from the inside to the outside. The perturbation is external.
Interesting. Thanks Chris.
Is conceiving of a body retaining any kind of external integrity a falsity as it transitions to > speed of light? Once inside the event horizon there is no "outside".

Are spacetime analogs, for instance, a type of internally-disallowed conceit?

Do metamaterials really exhibit these energies and effects, or merely highlight the limits of human measurement & apperception?
https://phys.org/news/2011-07-metamater ... runch.html

Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and the "end of time" arxiv.org/abs/1107.4053

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Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by Chris Peterson » Sat Jun 03, 2017 2:22 pm

douglas wrote:Is conceiving of a body retaining any kind of external integrity a falsity as it transitions to > speed of light? Once inside the event horizon there is no "outside".
The question is meaningless because no body transitions to greater than c. Photons and other zero rest mass particles always travel at c. Massive bodies always travel at less than c. That's why massive bodies can't orbit inside the photon sphere of a black hole (1.5 times the event horizon radius). If they could exceed c, they could continue to orbit.

There's no reason that a body wouldn't maintain its integrity inside the event horizon. In the case of a supermassive black hole, the tidal forces at the event horizon are small- you don't get spaghettification. A person in a space suit, for instance, would survive falling through the event horizon of a black hole. At that point, they're still outside the singularity.
Chris

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douglas

Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by douglas » Sat Jun 03, 2017 8:36 pm

I'm assuming Mr. Siegel's "no other explanation" means no outbursts at any wavelength were detected for this star, N6946-BH1's, disappearance.

https://blogs-images.forbes.com/startsw ... ?width=960

The visible/near-IR photos from Hubble show a massive star, about 25 times the mass of the Sun, that has winked out of existence, with no supernova or other explanation. Direct collapse is the only reasonable candidate explanation.
NASA/ESA/C. Kochanek (OSU)

"The 30-ish solar mass binary black holes first observed by LIGO are very difficult to form without direct collapse."

https://www.forbes.com/sites/startswith ... 1ee5f5216d

" ... By 2015, the Hubble and Spitzer telescopes couldn’t see it, nor could they detect any radiation coming from where it once was."
http://www.atlasobscura.com/articles/ma ... lapse-fail

"A small amount of IR light has been detected from where the star used to be. This radiation probably comes from debris falling onto a black hole."
http://www.sci-news.com/astronomy/red-s ... 04897.html

douglas

Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by douglas » Sat Jun 03, 2017 9:01 pm


douglas

Re: APOD: Black Holes of Known Mass (2017 Jun 02)

Post by douglas » Sun Jun 04, 2017 3:49 am

Speaking of Internally-disallowed conceits, this well-written article on problems ascertaining the proton's true diameter leaves one wondering if the methods used, smashing "particles" into targets at incredible energies, are merely muddying the results ..

" .. protons and neutrons contain much more. Quark-antiquark pairs constantly form and annihilate around the three persistent quarks."

https://www.sciencenews.org/article/the ... out-proton