Starship Asterisk*

[quote="Ellen Sentinel"]Thanks for the answer :) Never thought that two black holes can merge, rather imagined their interaction like that between a single hole and a star.[/quote]
Well, the two are very similar. When a black hole and a star come together, you could reasonably say they merge, as you are still left with a single black hole but now having the sum of the original masses (less some small losses given up as energy in the collision).

[quote="Chris Peterson"]
Eventually, one or two will be flung away at escape velocity, and the three will be in an open orbit, moving forever away from each other. It's extremely unlikely that two would collide, but it's possible. When two black holes come together, they coalesce into a single black hole with the mass of the two parents.[/quote]

Thanks for the answer :) Never thought that two black holes can merge, rather imagined their interaction like that between a single hole and a star.

[quote="ddorn777"]It is interesting to think that, I guess, our galaxy is rather average, for it's particular class, and our sun is rather average, as far as stars go (or maybe "common" would be the correct term). So does that make our planet "average" as well? Just how common IS intelligent life?[/quote]
I think our galaxy is rather above average in terms of mass. And I don't know what it means to suggest our sun is "average", given that stars in its class make up only a tiny fraction of all the stars in a galaxy.

It is interesting to think that, I guess, our galaxy is rather average, for it's particular class, and our sun is rather average, as far as stars go (or maybe "common" would be the correct term). So does that make our planet "average" as well? Just how common IS intelligent life?

[quote="geckzilla"]J1502+1115 is just a shorthand coordinate. In other words, the galaxy has no name.[/quote]

Thanks geckzilla :). I wonder if intelligent life in that galaxy think how unusual our Milky Way is in not having at least 3 blackholes! (as far as I'm aware it does not). The J1502+1115 'Galaxy Without A Name' could be GWAN1 in a GWAN catalogue (catalog in US spelling :wink: ).

If the Milky Way's size was compared to the billions of galaxies that I understand there are thought to be I wonder if it would be considered to be insignificant such that it is a GWAN elsewhere!

J1502+1115 is just a shorthand coordinate. In other words, the galaxy has no name.

I assume that 1115 in the galaxy J1502+1115 is the third blackhole. If so I would be grateful if anyone could inform me how far it is away from the pair of blackholes J1502SE and J1502SW. Also how far away from Earth is the galaxy, which also needs a better name than J1502+1115 though I guess giving a name to each is probably unrealistic in view of the billions of galaxies there may be out there! :wink:

Oops, my bad :oops:. I've now looked at the information brought up through the "J1502+1115 link and in that it states the galaxy is "more than 4 billion light years away". That just leaves how far away 1115 is from J1502SE/J1502SW.

Fully, exactly, whichever.

[quote="geckzilla"]Nobody understands exactly what happens when two black holes collide but I can't think of any event that might be more overwhelmingly violent (Big Bang itself?). I mean, how fast do two things so massive that light can't escape their gravity strike each other? Must be a lot of matter approaching c during such an event. Who the heck knows. I don't want to be in the same galaxy.[/quote]
Nobody [i]fully [/i]understands black hole collisions. They have been modeled numerically, however, so some details are probably understood. They are particularly interesting because they should be a source of gravitational waves, and detectors which are currently in operation or design are looking for such collisions (which are extremely rare, but extremely rare in an extremely large universe).

Nobody understands exactly what happens when two black holes collide but I can't think of any event that might be more overwhelmingly violent (Big Bang itself?). I mean, how fast do two things so massive that light can't escape their gravity strike each other? Must be a lot of matter approaching c during such an event. Who the heck knows. I don't want to be in the same galaxy.

[quote="hlwelborn"]"...100 million times the mass of our Sun."

I don't understand the use of the word "mass" in this sentence. Does this mean size or weight or ???[/quote]
Mass is [url=http://en.wikipedia.org/wiki/Mass]mass[/url]. A fundamental property of matter. A measure of energy (via E = mc[sup]2[/sup]).

Weight is another name for force, normally the force exerted on a massive body by gravity. Newton describe that as F = ma. The weight of an object is its mass times the acceleration of gravity it is experiencing. At 1 G, mass and weight typically have the same value (but different units).

[quote="Ellen Sentinel"]I can't help but wonder, just what will happen if one black hole gets gravitated by another and, eventually, falls into it? Is such an event possible?[/quote]
All three are gravitationally attracted by each other. That's what it means for them to be in a closed orbital system. Such systems are not stable, so this system will not last very long. Eventually, one or two will be flung away at escape velocity, and the three will be in an open orbit, moving forever away from each other. It's extremely unlikely that two would collide, but it's possible. When two black holes come together, they coalesce into a single black hole with the mass of the two parents.

[quote="hlwelborn"]"...100 million times the mass of our Sun."

I don't understand the use of the word "mass" in this sentence. Does this mean size or weight or ???[/quote]
Weight is a local measurement, made in relation to the gravitational attraction at the surface of a body. My weight on Earth is about 97 kg, but my weight on Mars would be about 38% of that, or about 37 kg -- because Mars is about 38% of the mass of the Earth while my mass remains the same. So weight isn't much use when you're talking about bodies in space.

When we refer to the mass of a body in space, we express it either in SI units, that is, as a certain number of kilograms, or we express it as a percentage or multiple of the mass of another body, as in your quote, "100 million times the mass of our Sun".

Size gets tricky when we talk about dense objects like stars and black holes. The atoms that make up the object get crushed tighter and tighter together by gravity as more of them are added, so really dense objects can be quite small. If our Sun were somehow compressed to the density of a black hole, it would be only about 3 km in radius, compared to its current radius of almost 700,000 km, yet would contain all its current mass.

I've probably just confused the issue more, but someone else will step in to clear up the mess if necessary. :)

Rob

I have run many simulation of a triple-mass orbital system, and never come up with anything that is stable over time. I am guessing that this is an intermediate stage of an evolving system that will eventually eject two of the primary bodies, with lots of fall out along the way.

Certainly adds a new meaning to the phrase 'ménage à trois'. :wink:

I can't help but wonder, just what will happen if one black hole gets gravitated by another and, eventually, falls into it? Is such an event possible?

[quote="Ron-Astro Pharmacist"]Fun APOD today but it makes me a little paranoid. Why do I feel someone is watching me?? :ninja: I'm hoping the eyes were added to simulate the radio waves. Art always adds a little something for our enjoyment.[/quote]
The white and grey ellipses represent two different point spread functions at two different wavelengths. You know how stars are really point sources but they spread out to look like fuzzy balls, sometimes with spikes? Same thing is going on here. The red outlines are just contours from the other wavelength. 5GHz is represented by the pixel color ramp. The second wavelength, 1.7GHz is represented by the red contours.

That's what I gather from the [url=http://arxiv.org/pdf/1406.6365v1.pdf]paper[/url], anyway. Interesting that they spread at different angles.

One learns so much new information on the this site. Without the first link I probably would never have known of the Dwingeloo Radio Observatory in the Netherlands let alone its named galaxies Dwingeloo 1 or 2. I wish our town had a radio telescope. It might discover a radio source behind M16's gas clouds that we would have to name the "Eagle" Nebula. Wait a minute – that sounds familiar.. :bang:


Fun APOD today but it makes me a little paranoid. Why do I feel someone is watching me?? :ninja: I'm hoping the eyes were added to simulate the radio waves. Art always adds a little something for our enjoyment.

"...100 million times the mass of our Sun."

I don't understand the use of the word "mass" in this sentence. Does this mean size or weight or ???

Interestingly, I see the Manhattan thumbnail above, but when I click the link I get the proper APOD image.

Rob

Don't trust astropix.html. Use http://apod.nasa.gov/apod/ap140707.html instead.
Why? See http://asterisk.apod.com/viewtopic.php?f=28&p=228728#p228728

I think there has been a slight mistake here. While Manhattan is mighty, it is not yet a galaxy with three black holes.

Ann

[url=http://apod.nasa.gov/apod/ap140707.html][img]http://apod.nasa.gov/apod/calendar/S_140707.jpg[/img] [size=150]J1502+1115: A Triple Black Hole Galaxy[/size][/url]

[b] Explanation: [/b] Most galaxies contain one supermassive black hole -- why does this galaxy have three? The likely reason is that galaxy [url=http://www.jive.nl/trio-supermassive-black-holes-shake-space-time]J1502+1115[/url] is the product of the recent coalescence of three smaller galaxies. The two closest black holes are [url=http://www.jive.nl/sites/jive.nl/files/cms/images/inner_pair_EVN.jpg]shown above[/url] resolved in [url=http://science.hq.nasa.gov/kids/imagers/ems/radio.html]radio waves[/url] by [url=http://en.wikipedia.org/wiki/European_VLBI_Network]large coordinated array[/url] of antennas spread out over Europe, Asia, and Africa. These two [url=http://apod.nasa.gov/apod/ap130312.html]supermassive black hole[/url]s imaged are separated by about 500 [url=http://chandra.harvard.edu/photo/cosmic_distance.html]light years[/url] and each has a likely mass about 100 million times the mass of our Sun. Currently, J1502+1115, at a [url=http://apod.nasa.gov/apod/ap130408.html]redshift[/url] of 0.39, is one of only a few triple black hole system known and is [url=http://arxiv.org/abs/1406.6365]being studied[/url] to learn more about galaxy and supermassive [url=http://science.nasa.gov/astrophysics/focus-areas/black-holes/]black hole[/url] interaction rates during the [url=http://en.wikipedia.org/wiki/Galaxy_formation_and_evolution]middle ages[/url] of our universe. [url=http://en.wikipedia.org/wiki/Gravitational_wave]Gravitational radiation[/url] emitted by such massive black hole systems may be detectable by [url=https://www.skatelescope.org/science/]future[/url] [url=http://lisa.nasa.gov/]observatories[/url].

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