Black Holes

[aramis]

When I hear about the event horizon, the gist I get from whatever physicist is talking about it, is that after the event horizon all the time dilation and other strange effects begin to take hold. At least that's what it sounds like some times, but I'm guessing what they really mean is that all the time dilation and stretching probably happens long before then.

The event horizon is the point where (1) everything below is black, (2) you're not leaving via N-space/NAFAL drives, and (3) you're no longer able to get a message out. In most cases, it's also the point where dilation is getting extreme enough that the universe becomes a blinding microwave glow...

 

[simonh]

This means that as r appoaches R_s time moves slower and slower until one reaches the event horizon (R_s = r), at which poiny t_d = 0 (i.e. time passes at 0 seconds per second as seen from a far distance - in other words, time stops at the event horizon).

I thought I'd found a way to get messages out of a black hole from below the event horizon without violating relativity, but this is what torpedoed my cunning plan.

The idea was to put relay stations at different orbital altitudes over the black hole. A laser signal sent from the event horizon or lower could never reach a distant target because it would get attenuated to zero, but if you could get a signal some fraction of the way out to a relay station, it could fire of a fresh, unattenuated signal - and so on. This could work if your black hole was big enough that tidal forces at the event horizon would be survivable for your space probe.

Of course time dilation means that while such a scheme is theoretically possible physically, it would take literaly foverver (infinite time, or more) for the signal to get out.

Dang it - back to the drawing board!

Simon Hibbs

 

[Blue Ghost]

This has always been a pet peeve of mine. Because of some of the spinning black holes eject energy laterally at the poles, then, by definition, light actually can escape via a vector using the right hand rule.

And, if that's the case, and if black holes are susceptible to stuff like gamma radiation, then their evaporation can be induced, and the effects of a black hole (in theory at least) negated.

If that's the case, then through some handwave "magic" tech, there might be a case for exploration of one of these beasts.

It just strikes me that the time dilation effect in and of itself may actually be subject to yet another frame of relativity, or, perhaps, that the severe effect of relativity is only apparent when within a certain radius of the black hole.

 

[whulorigan]

This has always been a pet peeve of mine. Because of some of the spinning black holes eject energy laterally at the poles, then, by definition, light actually can escape via a vector using the right hand rule.

The Relativistic Jets from the rotational poles are composed of material that has never fallen past the Event Horizon. The material originates in the accretion disk.

http://en.wikipedia.org/wiki/Astrophysical_jet

 

[tjoneslo]

The one thing that hasn't been considered here is how does the Gravity control technology present in Traveller alter the ability to get close to a black hole.

As described in canon (by complete non-physicists) the technology violates at least three fundamental laws of physics. In addition it never goes through all the implications of being able to manipulate a fundamental force with such ease.

Depending upon how you think the maneuver drive, repulsor beams, and gravity focusing elements for the laser system work in relation to gravity and relativity it may be possible to get a probe down to the event horizon and back out again. I'm not sure I'd want to try and get a person down there, as I'm quite sure they wouldn't survive.

So the probe has a repulsor bay on it, and a huge (for its size) overpowered m-drive. The two are build to interact in a way the probe creates a less bent section of space in a line out to the scout ship, a tunnel through the space bend by the black hole. This allows communication, and retrieval of the probe. In theory.

But, since the black hole is spinning, the tunnel created by the probe isn't straight. And as the black hole spins, the tunnel gets bent more and more until it breaks.

The other problem is all the material inside the black hole is terrifically compressed, and compressed material is very hot. But as the probe crosses the invisible event horizon, material inside the black hole can suddenly escape. Stuff so hot it has decomposed into it's quark state. It's going to come blasting out and will destroy everything in it's path.

 

[Blue Ghost]

The Relativistic Jets from the rotational poles are composed of material that has never fallen past the Event Horizon. The material originates in the accretion disk.

http://en.wikipedia.org/wiki/Astrophysical_jet

But we've got photos of stuff being ejected from spinning masses. If that were the case, then we wouldn't be able to capture those images.

It's probably a rare thing, and I'm guessing that most black holes actually do keep everything to themselves, but the fact that there seems to be a "right hand rule" in operation, makes me wonder about black holes, and specifically their true mechanics.

 

[whulorigan]

But we've got photos of stuff being ejected from spinning masses. If that were the case, then we wouldn't be able to capture those images.

All of the "photos" of stuff being ejected is material above the Event Horizon that has never fallen in. If it passes the Event Horizon, it is gone. Unless it can travel faster than light.

 

[Blue Ghost]

The one thing that hasn't been considered here is how does the Gravity control technology present in Traveller alter the ability to get close to a black hole.

As described in canon (by complete non-physicists) the technology violates at least three fundamental laws of physics. In addition it never goes through all the implications of being able to manipulate a fundamental force with such ease.

Depending upon how you think the maneuver drive, repulsor beams, and gravity focusing elements for the laser system work in relation to gravity and relativity it may be possible to get a probe down to the event horizon and back out again. I'm not sure I'd want to try and get a person down there, as I'm quite sure they wouldn't survive.

So the probe has a repulsor bay on it, and a huge (for its size) overpowered m-drive. The two are build to interact in a way the probe creates a less bent section of space in a line out to the scout ship, a tunnel through the space bend by the black hole. This allows communication, and retrieval of the probe. In theory.

But, since the black hole is spinning, the tunnel created by the probe isn't straight. And as the black hole spins, the tunnel gets bent more and more until it breaks.

The other problem is all the material inside the black hole is terrifically compressed, and compressed material is very hot. But as the probe crosses the invisible event horizon, material inside the black hole can suddenly escape. Stuff so hot it has decomposed into it's quark state. It's going to come blasting out and will destroy everything in it's path.

Well, I hate to admit it, but in my third or fourth semester of engineering physics I tinkered a little with gravity vectors. My math was inadequate, but using what I did know, it seemed to me that black holes were following another set of physics layered on top of quantum mechanics.

It seems to me that grav tech might allow closer inspection of black holes, but that would be a referee's call.

 

[RandyB]

Well, I hate to admit it, but in my third or fourth semester of engineering physics I tinkered a little with gravity vectors. My math was inadequate, but using what I did know, it seemed to me that black holes were following another set of physics layered on top of quantum mechanics.

It seems to me that grav tech might allow closer inspection of black holes, but that would be a referee's call.

It just occurred to me that Traveller grav tech could be explained (though likely not in OTU canon) as derived from more thorough and accurate examination of one or more black holes.

 

[whulorigan]

As described in canon (by complete non-physicists) the technology violates at least three fundamental laws of physics.

For the sake of the discussion (and so that we are on the same page), would you be able to list the 3 fundamental laws of physics to which you are referring?

In addition it never goes through all the implications of being able to manipulate a fundamental force with such ease.

Depending upon how you think the maneuver drive, repulsor beams, and gravity focusing elements for the laser system work in relation to gravity and relativity it may be possible to get a probe down to the event horizon and back out again. I'm not sure I'd want to try and get a person down there, as I'm quite sure they wouldn't survive.

To manipulate gravity directly, the problem is analogous to creating a force without creating the "charge" (in this case Mass) which gives rise to the force. It would be like trying to create a non-zero electric field without utilizing the electric charge from which the force arises. That is why I generally see gravitics as a force that is a corollary force arising from gravity (perhaps additional secondary fields that arise from gravity that can be manipulated or "screened" with respect to the actual gravitational field, or perhaps an effect that arises from gravity operating in multiple higher dimensions).

If gravitics works by taking advantage of an as-yet undiscovered corollary force to gravity (i.e. not changing the gravity itself but rather a secondary force reacting against the gravitational field)^*, then gravitics may not have any affect on time-dilation or space-time curvature (or have a tangential effect of some sort). If that is the case, then the shape of the Event Horizon and the corresponding temporal effects might remain largely unchanged. It would then simply be a matter of how much force can I exert to keep myself from falling in.

^* - Note that published Traveller material (MT, et al) has suggested that "Artificial Gravity" is a force related to but distinct from the normal gravitational force. (This is supposedly why artificial Gravity attenuates so rapidly).
​

OTOH, if gravitics does interact directly with gravity/spacetime-curvature, the gravitics may actually produce time dilation itself (although in every day situations, probably with minimal effect, similar to that experienced by GPS satellites orbiting at a higher gravitational potential than the Earth's surface). If a strong enough gravitic projector could be built under this presupposition, then I would think that the actual "shape" of the Event Horizon would be distorted as the gravitic field approaches (perhaps creating a "dimple" or "depression" in the locus of points defining the Horizon. I would think the new geometry would still define a barrier-limit to objects being able to leave the volume it encloses, however, since the Event Horizon corresponds to a mathematical surface along which time comes to a halt.

The other problem is all the material inside the black hole is terrifically compressed, and compressed material is very hot. But as the probe crosses the invisible event horizon, material inside the black hole can suddenly escape. Stuff so hot it has decomposed into it's quark state. It's going to come blasting out and will destroy everything in it's path.

By and large, the material that has fallen in will have been crushed to a point at the singularity of infinite density, since it would be necessary to travel faster than light in order to halt the downward motion.

 

[Blue Ghost]

Well, for gaming purposes, I think saying that there's tech to deal with extreme gravity is all you need. Wanting to explain that in terms of Traveller "hard science" is a different matter entirely, and may be up to a referee or some aspects of borrowed fiction.

 

[tjoneslo]

For the sake of the discussion (and so that we are on the same page), would you be able to list the 3 fundamental laws of physics to which you are referring?

The second law of thermodynamics - The energy required (as described) to move a mass is several orders of magnitude smaller than the energy you can get out of a system by moving that mass.

The Theory of General Relativity - As you note in your description, the question of how you bend space to provide gravity like effects without mass. More specifically, General Relativity defines gravity as an accelerating frame of reference with some specific characteristics. In order to describe how grav modules work, you need to break some part of GR to make it fit.

Quantum mechanics fundamental constants of the universe - The constants like speed of light, planck constant, mass of an electron, charge, etc are all related to one another. If you manipulate one, the leading contender is the the Higgs Field to make objects less massive by disconnecting them from the rest of the universe, all the other physical constants change too. It doesn't take a lot of changes to these physical constants to destroy everything in the field.

You could, correctly, argue that the latter violations would be affects of attempts to explain the earlier ones.

 

[WistfulD]

But we've got photos of stuff being ejected from spinning masses. If that were the case, then we wouldn't be able to capture those images.

It's probably a rare thing, and I'm guessing that most black holes actually do keep everything to themselves, but the fact that there seems to be a "right hand rule" in operation, makes me wonder about black holes, and specifically their true mechanics.

It is impossible to tell from the posts whether we've explained stuff to you enough for understanding. LEt's go over some basics:
1) No, it is not a rare thing, it is a never thing. If something passes the event horizon, it is gone. Stuff ejected from the black hole is from the accretion disk falling towards the black hole which gets energized by the tidal forces acting on it, and a small portion (usually high energy particles and EM energy) of it is violently shot back into space.
2) Gamma rays do not induce anything from a black hole except being absorbed by them. Black hole evaporation is a constant, continuous effect that happens automatically.
3) What exactly are the true mechanics that you want answered?

 

[Blue Ghost]

Mister WistfulD; I've read differently. There are thing called "ejection events" of bright plasma, usually associated with X-ray bursts. Maybe there's a black hole classification I'm not aware of that you're trying to tell me.

I did read your posts. Are you perchance a university professor?

 

[Adam Dray]

You're wrong, Blue Ghost. I think you misunderstood something you read.

Here's a pretty authoritative page that talks about the "ejection events" you mentioned:

To begin with, it sounds illogical that black holes could even generate massive eruptions. After all, hasn't it always been said that nothing, not even light, can escape a black hole? This remains true, but only when matter passes inside the "event horizon" of a black hole. This is a black hole's point of no return, when nothing is capable of escaping from its intense gravity. In other words, it's what puts the "black" in "black holes."

Matter that gets close to a black hole but remains outside the event horizon can undergo a very different experience and is sometimes expelled in violent jets. Such jets, probably originating from an energetic, magnetized, spinning disk around the supermassive black hole, produced the enormous cavities seen in MS 0735. The creation of these huge structures is a vivid demonstration of the enormous power that can be generated by supermassive black holes.

Emphasis added.

The event horizon is basically the boundary of the universe in space. The curvature of space becomes so "steep" at that point that the laws of physics as we understand them allow nothing -- no form of matter or energy -- to return.

The so-called "loopholes" are things like Hawking radiation (which relies upon the event horizon to work), which rips a virtual particle in half. Half goes into the black hole, never to be heard from again. The other half escapes the gravity well as radiation.

 

[aramis]

Mister WistfulD; I've read differently. There are thing called "ejection events" of bright plasma, usually associated with X-ray bursts. Maybe there's a black hole classification I'm not aware of that you're trying to tell me.

I did read your posts. Are you perchance a university professor?

THat's a result of impact outside the event horizon. The eejecta is material in non-equatorial orbit that approaches (but does not cross) the horizon.

Time dilation due to gravity and due to speed prevents the near-C object from crossing the event horizon and escaping, as it is below orbital velocity at crossing.

The only possible way out is some version of FTL drive, or QM & GR being dead F*ing wrong.

 

[Blue Ghost]

Can anyone recommend a good reference on the subject? Because I'm just going by what I see in various documentaries and calling up my college astronomy as best as I can.

 

[rancke]

I could have sworn that I've read somewhere that Stephen Hawking had figured out that black holes lose mass over time and eventually dissipate (If they're not fed).


Hans

 

[Lycanorukke]

I could have sworn that I've read somewhere that Stephen Hawking had figured out that black holes lose mass over time and eventually dissipate (If they're not fed).Hans

Yup. Via Hawking Radiation.

With vacuum energy you have particle/antiparticle pairs popping into existence all the time, but because they annihilate each other immediately after, conservation of energy is not violated.

However if they pop into existence very close to the event horizon, one of the pair may get ‘eaten’ by the black hole, while its partner escapes. Now that the virtual particles are ‘real’ the black hole has to make up the energy debt and thus loses a bit of mass. Eventually the hole loses all its mass and evaporates in a flash of radiation, though this still takes an incredibly long time. (A solar mass black hole takes about 10^60 years to evaporate)

An interesting effect of pair production is if a virtual particle pair pops into existence just inside the event horizon and one of them quantum tunnels out of the black hole while its partner is left behind. The effect is the same as the pair popping into existence outside the hole, but it means a tunnelling effect can technically escape from inside the event horizon.

Now 2300 Stutterwarp ships which achieve FTL by tunnelling on a macro scale….

 

[aramis]

I could have sworn that I've read somewhere that Stephen Hawking had figured out that black holes lose mass over time and eventually dissipate (If they're not fed).


Hans

That's Hawking Radiation. Which has been mentioned above several times. The quantum dislocation of particle/antiparticle pairs onto the horizon followed by one of the pair falling inside the horizon and the other colliding with infalling but still external to the horizon matter. Either way, a small amount of energy escapes.

If, however, Hawking's radiation is due to random pair spontaneous generation rather than quantum dislocation, the whole thing fails, because then the hole continues to feed even in empty space.

Not that everyone working in the field even accepts the virtual partical pair (VPP) phenomenon, anyway, and even some who do reject Hawking Radiation as they believe it's spontaneous generation instead of quantum dislocation. And, if you can get the VPP as spontaneous generation, then you also have potential Zero Point Energy - just collide the wrong particle with it, and the energy release from the impact of the one and the annihilation of the other...