Balck Holes too soft

[Suicide Junkie]

quote:

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Originally posted by raynor:
If I take an object with arbitrary mass and vector, it sounds to me like you are saying that when it approaches a stellar body of planetary mass or larger, there is a 100% guarantee that said object will enter into stable orbit around the stellar body?

Fascinating...

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Noooo. I'm saying that the Captain of said object would put his ship in orbit, assuming that he's not suicidal.

The other thing that I'm saying is that anything already in orbit will not fall out of orbit just because its orbiting a black hole.

[Dracus]

I have done some more research.

There is no limit in principle to how much or how little mass a black hole can have. Any amount of mass at all can in principle be made to form a black hole if you
compress it to a high enough density. We suspect that most of the black holes that are actually out there were produced in the deaths of massive stars, and so we expect
those black holes to weigh about as much as a massive star. A typical mass for such a stellar black hole would be about 10 times the mass of the Sun, or about 10^{31}
kilograms. (Here I'm using scientific notation: 10^{31} means a 1 with 31 zeroes after it, or 10,000,000,000,000,000,000,000,000,000,000.) Astronomers also suspect that
many galaxies harbor extremely massive black holes at their centers. These are thought to weigh about a million times as much as the Sun, or 10^{36} kilograms.

The more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius (which means the radius of the horizon) and the mass are directly
proportional to one another: if one black hole weighs ten times as much as another, its radius is ten times as large. A black hole with a mass equal to that of the Sun
would have a radius of 3 kilometers. So a typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a
galaxy would have a radius of 3 million kilometers. Three million kilometers may sound like a lot, but it's actually not so big by astronomical standards. The Sun, for
example, has a radius of about 700,000 kilometers, and so that supermassive black hole has a radius only about four times bigger than the Sun.

A black hole has a "horizon," which means a region from which you can't escape. If you cross the horizon, you're doomed to eventually hit the singularity. But
as long as you stay outside of the horizon, you can avoid getting sucked in. In fact, to someone well outside of the horizon, the gravitational field surrounding a black hole
is no different from the field surrounding any other object of the same mass. In other words, a one-solar-mass black hole is no better than any other one-solar-mass
object (such as, for example, the Sun) at "sucking in" distant objects.

A black hole in a close orbit around a star can pull the top layers of the star off the surface and
down its own gravity well. Once the material passes beyond the black hole's event horizon, it is
gone, and more stuff can be consumed by the black hole. You are left with a slightly larger black
hole, and a slightly less massive star, so the black hole can pull a little more material off the star.
This continues until the star is gone, and the black hole's hunger is yet unabated.

[Nitram Draw]

If you are interested in Black Holes and such there is up to date info at www.chandra.harvard.edu

[This message has been edited by Nitram Draw (edited 30 March 2001).]

[Dracus]

here is a cool drawing of a sun being lunch for a black hole.
came from that site.




[This message has been edited by Dracus (edited 30 March 2001).]

[Dracus]

if any is interested, I found an article on how a wormhole may in theory exist/work.

[Suicide Junkie]

Agggh!

Let me make it as simple as I can.

It dosen't matter whether you are talking about:
- your ship VS an asteroid
- your ship VS a planet
- your ship VS a star
- your ship VS a Black Hole

IN orbit ==> stay in orbit ==> no crash
Not IN orbit (eg. stationary) ==> fall in ==> die horrible death

quote:

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In other words, a one-solar-mass black hole is no better than any other one-solar-mass object (such as, for example, the Sun) at "sucking in" distant objects.

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Yes! Exactly.

quote:

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A black hole in a close orbit around a star can pull the top layers of the star off the surface and down its own gravity well. Once the material passes beyond the black hole's event horizon, it is gone, and more stuff can be consumed by the black hole. You are left with a slightly larger black hole, and a slightly less massive star, so the black hole can pull a little more material off the star

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Now, one caution here:
The Hole isn't "sucking" the gas off of the star. The star's gas is slowly smeared out by the gravitational shear & drifts into the accretion disk, which radiates energy & sinks towards the hole.

The Hole & star are orbiting each other, but lets take the viewpoint of the hole.
Relative to us, we aren't moving.
The star is orbiting us, but it is really fat compared to the hole.
Now, imagine drawing an ellipse (circle) tracing out the star's path. Some of the star's gas is too far out & some is too far in. The farther out the orbit, the slower you move, so the outside (away from the hole) is moving too fast for it's orbital distance, while the inside is moving too slow.

The Gas that's moving too slow tends to drop inwards towards the hole, while the fast gas stretches outwards. The slow gas transfers from orbiting the star to the hole, where it joins the accretion disk.

The accretion disk radiates heat from the friction between different layers (inner ones orbit faster) and the gas loses energy & slowly falls in.

[Dracus]

All this stuff That I have posted comes from a number of research web sites, word for word.

Things would only orbit as long as they were outside the horizon. Different sites describe the Horizon a little different, but this may be due to the fact that no one has ever been near an actual black hole. Some say the horizon is were the grav pull increases, some say it is were light can no longer escape. either way, inside the horizon, you die. So there for I stand corrected. But we must all agree, that until we actual travel to a real black hole, we will truely never know. So everything you stated is based on the rules that man thinks it understands. But the universe has a way of surpising us now and then.

Here is a question for you--could our sun become a black hole?

I'm out




[This message has been edited by Dracus (edited 30 March 2001).]