Balck Holes too soft

[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).]

[CaptSpoogy]

I don't know a whole bunch about black holes and other phenomenon but here is my question:

A black hole has a huge mass right? So if a ship tried to orbit it, would it take lots of energy to remain in orbit?

Just Curious.

BY THE WAY, have you stopped by the updated Spoogy Federation website?
http://spoogyfederation.tripod.com

[raynor]

If a spacecraft the size of the shuttlecraft exited a hypothetical wormhole and found itself 100 KM from the outer corona of a star the size of our sun, what velocity would that spacecraft have to achieve in order to maintain a stable orbit around the star?

A multi-part question

1. A spacecraft the size of the shuttle approaches our sun on a course aimed directly for the 'center' of the star.
2. Take the main engines used to achieve escape velocity out of the equation.
3. Assume the spacecraft doesn't use any fuel until it reaches closest approach.
4. Assume that heat/radiation aren't a factor--robotic pilot if you want.

How close do you think the spacecraft can get to our sun before it must alter its course to try to enter an orbit around the star?

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

[Steve A]

Raynor,
Orbital velocity at the sun's surface is 436 km/s. Spacecraft size does not matter as long as it is significantly smaller than the sun in mass.

If a ship fell towards the sun's surface from very far away, it would be traveling roughtly at escape velocity straight towards the core when it hits the surface. That velocity is 616 km/s at the sun's surface. To get into a circular orbit at that point, you would have to reverse the 616 km/s to stop the fall and add 436 km/s sideways to enter orbit. You can do both at once (a**2 + b**2 = c**2) with a delta velocity of 755 km/s.

The game engines don't really use delta V so it's hard to answer your question. The various books and board games SE4 is loosely based on have engines that propel spacecraft at 1% to 5% of lightspeed (3000 km/s to 15000 km/s), so it should be no problem for them to hover over the surface of the sun.

Steve



[This message has been edited by Steve A (edited 31 March 2001).]

[Steve A]

capt_spoogy,
Black holes can come in many masses, from around 5 solar mass to millions of solar masses. The energy it takes to get into orbit around a 5 solar mass black hole is exactly the same as the energy it takes to get into orbit around a 5 solar mass star.

Steve

[Steve A]

Dracus,
No, our sun will eventually end up as a white dwarf unless somebody uses a stellar converter on it.

<grin>

Steve