APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

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APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby APOD Robot » Sun Oct 22, 2017 4:06 am

Image Two Black Holes Dancing in 3C 75

Explanation: What's happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves.

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Guest » Sun Oct 22, 2017 6:48 am

so...if not even light is supposed to escape a black hole, how do these emit streams? and why doesn't the other's gravitational field suck it up when it orbits around?

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Boomer12k » Sun Oct 22, 2017 7:51 am

Guest wrote:so...if not even light is supposed to escape a black hole, how do these emit streams? and why doesn't the other's gravitational field suck it up when it orbits around?


I don't think the X-rays are "escaping the black holes". It is the GAS surrounding the black holes that emit the xrays... here is a simulation...watch the whole thing as there are inserted comments, and indications...

https://hub.jhu.edu/2013/06/14/black-holes-x-ray-light/

As to your second question. I am not sure, maybe they are too fast... they are X rays... ALSO, the ANGLES of the accretion disks could be "aimed" at different angles than their trajectories... thus, they "miss"... My uneducated guess...

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Astronymus » Sun Oct 22, 2017 11:11 am

Guest wrote:so...if not even light is supposed to escape a black hole, how do these emit streams? and why doesn't the other's gravitational field suck it up when it orbits around?

The jets are formed by gas and particles of the accretion disc that just escape the black hole. Like gaining speed by a malstroem but skipping off the edge. Keep in mind that magnetic fields are also involved. The superheated matter emits light and x-rays that we can detect.
Only matter and light that reached the event horizon is "gone".

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby heehaw » Sun Oct 22, 2017 11:19 am

Here is a link to the UPDATED chart of detected gravitational waves: https://www.ligo.caltech.edu/system/avm ... 1508029040

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby NCTom » Sun Oct 22, 2017 12:45 pm

Thanks, Boomer, for the article. Fascinating image and information.

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby neufer » Sun Oct 22, 2017 12:58 pm

Click to play embedded YouTube video.


APOD Robot wrote:Image Two Black Holes Dancing in 3C 75

Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Spif » Sun Oct 22, 2017 5:04 pm

Wow, two supermassives that will eventually merge? Spectacular image.

Are there any estimates on the actual mass of these two black holes? Supermassive means on the order of millions or billions of solar masses, but that's a fairly wide range.

I wonder what the gravitational waves from this event would feel like if you were orbiting nearby? (It looks like the Schwarzchild radius of a supermassive BH can be on the order of billions of kilometers so "nearby" to such an event might be like a Kuiper belt orbit or something ;)

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Sun Oct 22, 2017 9:34 pm

I think, also, that since they're 300 Ml ly distant, that "merge" is already happened... by now...
Terrific...

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Ann » Mon Oct 23, 2017 2:32 am

distefanom wrote:I think, also, that since they're 300 Ml ly distant, that "merge" is already happened... by now...
Terrific...


Arguably the merger "hasn't happened" from our point of view if the signal of the merger hasn't reached us yet.

I remember reading about a possible "configuration" of the Universe that might conceivably mean that the Universe was resting on a sort of "energy platform", from which it (or part of it) could suddenly "fall down" into an energy minimum, where there would be no energy left to run anything - stars, the photosynthesis, the metabolism of humans etcetera. If such a universal plunge into a state of energy minimum happened, it would be like a wall of destruction rushing through the Universe at the speed of light, but we would have no clue of what was happening until the signal of destruction hit us at the speed of light.

That scenario is very speculative, I think. The danger of something like that happening is minute, I would think. But ever since I read about that, I have concluded that nothing in the Universe "has happened" from our point of view until it has happened to us.

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby neufer » Mon Oct 23, 2017 2:40 am

Click to play embedded YouTube video.
Ann wrote:
I remember reading about a possible "configuration" of the Universe that might conceivably mean that the Universe was resting on a sort of "energy platform", from which it (or part of it) could suddenly "fall down" into an energy minimum, where there would be no energy left to run anything - stars, the photosynthesis, the metabolism of humans etcetera. If such a universal plunge into a state of energy minimum happened, it would be like a wall of destruction rushing through the Universe at the speed of light, but we would have no clue of what was happening until the signal of destruction hit us at the speed of light... ever since I read about that, I have concluded that nothing in the Universe "has happened" from our point of view until it has happened to us.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby neufer » Mon Oct 23, 2017 3:36 am

Spif wrote:
Wow, two supermassives that will eventually merge? Spectacular image. Are there any estimates on the actual mass of these two black holes? Supermassive means on the order of millions or billions of solar masses, but that's a fairly wide range. I wonder what the gravitational waves from this event would feel like if you were orbiting nearby? (It looks like the Schwarzchild radius of a supermassive BH can be on the order of billions of kilometers so "nearby" to such an event might be like a Kuiper belt orbit or something ;)

    1) Static gravitational tidal forces drop off rapidly (as 1/r3)... so rapidly, in fact, that a human falling through the very large Schwarzchild radius of a supermassive BH would not be noticeably affected.

    2) Dynamic gravitational tidal forces drop off slowly (as 1/r) ... but at no point do they ever exceed the static gravitational tidal forces at the event horizon.

    Ergo...whenever you are outside the event horizons of supermassive BHs
    you should have not problem with either static or dynamic gravitational tidal forces.
https://en.wikipedia.org/wiki/Laser_Int ... le_mergers wrote:
<<The Laser Interferometer Space Antenna (LISA), is a European Space Agency mission designed to detect and accurately measure gravitational waves from astronomical sources.

LISA will be able to detect the gravitational waves from the merger of a pair of (super)massive black holes with a chirp mass between 103 and 107 solar masses all the way back to their earliest formation at redshift around z ≈ 15. The most conservative population models expect at least a few such events to happen each year. For mergers closer by (z<3), it will be able to determine the spins of the components, which carry information about the past evolution of the components (e.g. whether they have grown primarily through accretion or mergers). For mergers around the peak of star formation (z ≈ 2) LISA will be able to locate mergers within 100 square degrees on the night sky at least 24 hours before the actual merger, allowing electromagnetic telescopes to search for counterparts, with the potential of witnessing the formation of a quasar after a merger.>>
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Mon Oct 23, 2017 6:58 am

Ann wrote:
distefanom wrote:I think, also, that since they're 300 Ml ly distant, that "merge" is already happened... by now...
Terrific...


Arguably the merger "hasn't happened" from our point of view if the signal of the merger hasn't reached us yet.

I remember reading about a possible "configuration" of the Universe that might conceivably mean that the Universe was resting on a sort of "energy platform", from which it (or part of it) could suddenly "fall down" into an energy minimum, where there would be no energy left to run anything - stars, the photosynthesis, the metabolism of humans etcetera. If such a universal plunge into a state of energy minimum happened, it would be like a wall of destruction rushing through the Universe at the speed of light, but we would have no clue of what was happening until the signal of destruction hit us at the speed of light.

That scenario is very speculative, I think. The danger of something like that happening is minute, I would think. But ever since I read about that, I have concluded that nothing in the Universe "has happened" from our point of view until it has happened to us.

Ann


I do not agree completely...
If I cut my hairs this morning, and you'll know it this evening; this won't mean that I've not cut my hairs THIS MORNING.
I think the "problem" of "knowing" if it happened or not, is only due to the speed of light, which can carries the "information"....
This is, at least, what i've understood in your comment.
Please let me know if I'm wrong in your understanding.
ciao
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby geckzilla » Mon Oct 23, 2017 7:19 am

distefanom wrote:I do not agree completely...
If I cut my hairs this morning, and you'll know it this evening; this won't mean that I've not cut my hairs THIS MORNING.
I think the "problem" of "knowing" if it happened or not, is only due to the speed of light, which can carries the "information"....
This is, at least, what i've understood in your comment.
Please let me know if I'm wrong in your understanding.

No one had to time-travel to find out your hairs were cut, though. Anywhere within less than a second light travel time may as well count as "now" but places much farther than that are at a significantly different point in time... it is not simply an arbitrary measurement made by some invented clock. Light is not simply carrying information. It is moving through time to get to us.
Just call me "geck" because "zilla" is like a last name.

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Ann » Mon Oct 23, 2017 11:42 am

Thanks for your excellent answer, Geck.

If you cut your hair, distefanom, you could, in theory at least, speak to me over the phone in real time and inform me that it was happening. Better yet, you could Skype me, so I could see in real time that your hair was being cut. But wait a minute, isn't there any sort of delay if you call me from, say, the United States, when I am in Sweden?

Well, there would be a slight delay. Assuming we could make light orbit the Earth, it would make seven full orbits in one second. So if you are on the other side of the Earth, and you call me or Skype me, there should be a time delay of something like one fourteenth of a second. Not a lot. I could see you having your hair cut and comment on your new hairstyle one fourteenth of a second after the barber used his scissors on you. We are not likely to notice that slight time difference.

(And Art and Chris and the other math whizzes here could give you a much more accurate calculation of the greatest time delay possible here on Earth. But you get my point.)

I remember the Moon landings (yes, I do). The average light speed distance between the Earth and the Moon is about 1½ seconds, so when the reporter on the Earth asked some astronauts a question, it took about three seconds before we could hear the astronauts' answer. The time delay was very noticeable.

And if some people manage to make it to Mars, and if we want to radio a question to them, it would take a minimum of eight minutes before we could hear their answer. Send other people to Alpha Centauri in the future, send them a question when we believe that they have arrived at their destination, and it would take a minimum of eight years before we could hear their answer.

And imagine that we sent a signal of some sort to the Andromeda galaxy, and imagine that someone in our sister galaxy heard our call and wanted to contact us. Of course, it would take our signal about two million years to reach Andromeda in the first place, and maybe possibly maybe humanity won't even exist two million years from now. In any case, anyone in Andromeda who heard our call would have to exist two million years from now, when our signal finally made it there. And if that person (or being) sent us a reply, it would take another two million years to reach us. Would we be here to answer? And if we did, would the species in Andromeda that answered our first call be there to answer our follow-up message another two million years into the future?

The farther away in space that an event takes place, the more it is cut off from our own reality here on Earth. If that expedition bound for Alpha Centauri failed and everyone on board died, when would we know it had happened?

Ann
Last edited by Ann on Mon Oct 23, 2017 11:32 pm, edited 1 time in total.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby neufer » Mon Oct 23, 2017 4:08 pm

Click to play embedded YouTube video.
Ann wrote:
If you cut your hair, distefanom, you could, in theory at least, speak to me over the phone in real time and inform me that it was happening.

I remember the Moon landings (yes, I do). The average light speed distance between the Earth and the Moon is about 1½ second, so when the reporter on the Earth asked some astronauts a question, it took about three seconds before we could hear the astronauts' answer. The time delay was very noticeable.

:arrow: It's not even clear if the Earth & Moon share the same calendar.
Last edited by neufer on Mon Oct 23, 2017 9:52 pm, edited 1 time in total.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Mon Oct 23, 2017 8:59 pm

The delay between trasmission and receive, it's a thing I know very well.
It's the same question I asked to my Phisics teacher at the high school over 30 years ago (don't be afraid Ann: I do remember Moon landings too).
The question is: i.e. If I snap my fingers now... is this moment (instant) the SAME BY DEFINITION (not because I can measure it) in ALL THE UNIVERSE?
My she-techer (and also I do) gave me the answer: YES
Conseguently the "APOD portrait" snapshot of two dancing BH are a snapshot of something on it's way to happen around 300 Ml years ago, when the two objects where still 25000 light years apart.
But NOW (and with "NOW" I mean the instant indicated by my "finger snap" above) the coalescing event is ALREADY HAPPENED.
And we all know this is the reality, even if we still can't see it yet.
We should wait another (at least) 25000+ years to actually "see" in a similar portrait what is happened AFTER the final BH "touch down".
Hope is clearer now.
ciao
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Chris Peterson » Mon Oct 23, 2017 9:20 pm

distefanom wrote:The question is: i.e. If I snap my fingers now... is this moment (instant) the SAME BY DEFINITION (not because I can measure it) in ALL THE UNIVERSE?
My she-techer (and also I do) gave me the answer: YES

Basically, she was wrong. The way physicists generally look at it, when an event happens at some time, it is happening elsewhere at a later time. "Now" isn't a well defined concept. It is generally tied to causality, which is tied to the speed of light.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Tue Oct 24, 2017 2:42 pm

Chris Peterson wrote:
distefanom wrote:The question is: i.e. If I snap my fingers now... is this moment (instant) the SAME BY DEFINITION (not because I can measure it) in ALL THE UNIVERSE?
My she-techer (and also I do) gave me the answer: YES

Basically, she was wrong. The way physicists generally look at it, when an event happens at some time, it is happening elsewhere at a later time. "Now" isn't a well defined concept. It is generally tied to causality, which is tied to the speed of light.


Ciao Chris,
so, one can say that the two BH haven't still "kissed" each other, they haven't merged together even thou, we all know, this is already happened, long time ago...
From my p.o.v. it seems like to say that Mr. OBAMA do not exist, only because I could never met him in my lifetime.
...INTERESTING !!! :D 8-)

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Chris Peterson » Tue Oct 24, 2017 2:52 pm

distefanom wrote:
Chris Peterson wrote:
distefanom wrote:The question is: i.e. If I snap my fingers now... is this moment (instant) the SAME BY DEFINITION (not because I can measure it) in ALL THE UNIVERSE?
My she-techer (and also I do) gave me the answer: YES

Basically, she was wrong. The way physicists generally look at it, when an event happens at some time, it is happening elsewhere at a later time. "Now" isn't a well defined concept. It is generally tied to causality, which is tied to the speed of light.


Ciao Chris,
so, one can say that the two BH haven't still "kissed" each other, they haven't merged together even thou, we all know, this is already happened, long time ago...
From my p.o.v. it seems like to say that Mr. OBAMA do not exist, only because I could never met him in my lifetime.
...INTERESTING !!! :D 8-)

Since the observation of the collision will mark the beginning of anything we can possible see, including all the effects the collision might have on other structures, that really becomes the "when". About the only time when we give a lot of consideration to a different kind of "when" is when something happened so long ago that we're observing the Universe in a significantly different evolutionary state (e.g. early galaxy formation).
Chris

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Tue Oct 24, 2017 5:43 pm

Another question : Imagining two BH spinning each other in a similar way ; but at so high speed, mass, rotation speed, angle so that they could only "touch" each other, and "bounce" away again, for the cinetic energy, instead of coalescing... Could this (at least) teorically happen?

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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby Chris Peterson » Tue Oct 24, 2017 5:59 pm

distefanom wrote:Another question : Imagining two BH spinning each other in a similar way ; but at so high speed, mass, rotation speed, angle so that they could only "touch" each other, and "bounce" away again, for the cinetic energy, instead of coalescing... Could this (at least) teorically happen?

No. Remember that when the collision happens, both black holes are already inside the same event horizon.
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Re: APOD: Two Black Holes Dancing in 3C 75 (2017 Oct 22)

Postby distefanom » Tue Oct 24, 2017 6:13 pm

Hi Chris
Thanks for your kind response.
I just visited also, your Cloudbait Observatory and I want make you a *lot* congratulations for your activity!!!
The instrumentation set is *serious* for a probate Astronomer!!!
I appreciate your wonderful initiative and the photo gallery.
You, As a private, can say it's more than FANTASTIC!
I just bookmarked the website!


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