by Chris Peterson » Tue Apr 25, 2017 10:25 pm
warmingwarmingwarming wrote:Chris Peterson wrote:Timbo69 wrote:When I look at a spiral galaxy, it appears to me like a drain, with much debris swirling to it's inevitable end, being sucked up by the huge super massive black holes at the center of it, like a huge water drain, all the debris, not really moving relative to its medium (the water), but just being sucked up by the flow of the medium, eventually, down the drain, except in this example, all the individual clumps of matter are also holes, and each hole an accumulation of many many smaller holes, any debris in the water can not fit down the drain, so it must clump together, and increase the size of the drain, causing an even faster flow, while it itself is being dragged.
Yet, this is just an illusion. In reality, nothing in a galaxy is being pulled into the center. Stars and gas follow approximately circular orbits. The central black hole, even in galaxies with active nucleuses, only absorbs
an insignificant amount of mass, and that from very, very close to it.
" ....
an insignificant amount of mass per unit of time only .. very significant over a larger unit of time .. also, according to your comment, each black hole should be surrounded by massless space, the black hole having consumed everything close to it, unless the universe was created, like, yesterday or the day before.
No, an insignificant amount of mass compared with the mass of the galaxy, and over billions of years. There is nothing that allows material to generally get closer to the center of a galaxy. A black hole only collects mass when there is some mechanism to bleed that mass of angular momentum. One is gravitational radiation, but that is only significant when a body is orbiting almost at the event horizon. The other is when gas or dust is dense enough that it acts like a fluid, and there are frictional losses. That's what forms an accretion disk. But most black holes don't have those, and most supermassive black holes only have them occasionally.
From the standpoint of a body orbiting a ways out from the center, the central mass is dominated by stars, not the black hole.
[quote="warmingwarmingwarming"][quote="Chris Peterson"][quote="Timbo69"]When I look at a spiral galaxy, it appears to me like a drain, with much debris swirling to it's inevitable end, being sucked up by the huge super massive black holes at the center of it, like a huge water drain, all the debris, not really moving relative to its medium (the water), but just being sucked up by the flow of the medium, eventually, down the drain, except in this example, all the individual clumps of matter are also holes, and each hole an accumulation of many many smaller holes, any debris in the water can not fit down the drain, so it must clump together, and increase the size of the drain, causing an even faster flow, while it itself is being dragged. [/quote]
Yet, this is just an illusion. In reality, nothing in a galaxy is being pulled into the center. Stars and gas follow approximately circular orbits. The central black hole, even in galaxies with active nucleuses, only absorbs [color=#FF0000]an insignificant amount of mass[/color], and that from very, very close to it.[/quote]
" .... [color=#FF0000]an insignificant amount of mass[/color] per unit of time only .. very significant over a larger unit of time .. also, according to your comment, each black hole should be surrounded by massless space, the black hole having consumed everything close to it, unless the universe was created, like, yesterday or the day before.[/quote]
No, an insignificant amount of mass compared with the mass of the galaxy, and over billions of years. There is nothing that allows material to generally get closer to the center of a galaxy. A black hole only collects mass when there is some mechanism to bleed that mass of angular momentum. One is gravitational radiation, but that is only significant when a body is orbiting almost at the event horizon. The other is when gas or dust is dense enough that it acts like a fluid, and there are frictional losses. That's what forms an accretion disk. But most black holes don't have those, and most supermassive black holes only have them occasionally.
From the standpoint of a body orbiting a ways out from the center, the central mass is dominated by stars, not the black hole.