Even high-speed mergers keep an event horizon
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Friday, October 3rd, 2008
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HEAD-ONA computer simulation shows that two black holes of equal mass colliding at close to the speed of light — an extreme scenario — form a new black hole and release energy in the form of gravitational waves.Sperhake et al. No matter how hard you try to push their boundaries, black
holes always seem to preserve their modesty. Indiscreet astrophysicists have simulated
the most violent collisions of black holes yet, and found that the resulting black
hole still has an event horizon — the surface through which even light cannot
escape and that hide black holes’ interiors.
An international team of researchers created a computer
simulation of what they call the most violent collision imaginable: Two black
holes of equal masses smashing into each other head-on, moving at close to the
speed of light.
Previous studies have suggested that when black holes collide
they merge into one larger black hole, radiating huge amounts of energy in the
form of gravitational waves — ripples in the very shape of space — that travel
at the speed of light. This study’s results were no exception. But the extreme
velocities of the team’s simulated black holes led to waves of unprecedented
energy. Up to 14 percent of the black holes’ masses, instead of just a few
percentage points, was converted into gravitational waves, the team reports in
an upcoming Physical Review Letters.
The simulations also showed that the resulting black hole
conformed to a long-standing conjecture, often attributed to Roger Penrose of
the University of Oxford in England and called the cosmic
censorship hypothesis.
SIDESWIPE A slightly more realistic scenario in which the collision of two black holes is not exactly head-on. The result is still a black hole, including its event horizon.Sperhake et al. Physicists believe that at the center of every black hole
lies a singularity, a region where space curls up so much that the known laws
of physics cease to apply, including general relativity, Albert Einstein’s
theory of gravity. But a black hole’s event horizon prevents the singularity
from interacting with the outside world.
Mathematically, “naked” singularities, or those without
event horizons, can exist, but physicists wouldn’t know what to make of them.
All known mechanisms for the formation of singularities also create an event
horizon, and Penrose conjectured that there must be some physical principle — a
“cosmic censor” — that forbids singularity nakedness, explains coauthor
Emanuele Berti of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We hope
it’s true,” he says of the cosmic censorship hypothesis, “because it basically
hides the failures of general relativity behind the event horizon.”
The scenario that Berti and colleagues simulated was
admittedly unrealistic because real black holes would not travel at close to
the speed of light. But even in such extreme conditions, the event horizon
draping wasn’t lost.
Greg Cook of Wake Forest University
in Winston-Salem, N.C., says that the results are interesting,
but that many questions remain. What happens, for example, when the ultrafast colliding
black holes have different masses, or are rapidly spinning?
Coauthor Ulrich Sperhake, now at Caltech, says that his and
other teams will keep trying to produce naked singularities, but that he doubts
that they really exist. “If you ask me, ‘What am I going to put my next two
salaries on?’ That Penrose was right.”
Found in: Atom & Cosmos
I wonder if anyone has considered black-holes produced by the aggregation of pure electrons, i.e., maximally mass-specific electrically charged black holes, wherein the electrical charge would have been instilled in a volume of space that is equal to or smaller than the volume that would result in the formation of an event horizon otherwise. Perhaps some exotic means could produce such a black hole perhaps by teleportation of the electrical charge, instillation of the charge by wormholes etc.
Perhaps the “black-holes” thus formed would have an un-cloaked singularity being that the electromagnetic force is approximately 10 EXP 40 times stronger than the gravitational force. It is interesting to consider whether an asymmetrically or non-spherically disposed electrical charge distribution within such a would be event horizon would be felt as non-symmetric electrical field flux lines extending out from the would be event horizon of such a black-hole.
It is interesting to consider the collision of two such super-charged such black-holes wherein the electrical charge instilled within each black hole would have the same sign and the same magnitude, the caveat being the ability to produce macroscopic black holes with enough collision energy in consideration of the enormous repulsive forces that would be felt between such black holes before they would merge. Pairs of black holes with differing masses and therefore differing quantities of electrical charge of the same sign could also be modeled.
Another possibility is to model black holes that have opposite signed electrical charges such as might, for the sake of argument, be produced, one from positrons and one from electrons, wherein the black holes would attract each other with veracious force and the resulting unheard of gamma factors that could result by such acceleration thus leading to unheard of gamma factor collisions. Perhaps it is even possible that the black holes coulombic attraction in the case of oppositely charged black holes, or coulombic repulsion in the case of black holes of the same sign charge would be enough to pull the black holes apart before they could merge.
An interesting case to study would be a model of two oppositely charged black holes wherein the magnitude of the charge on one black hole differs from that of the other black hole wherein the black hole so formed by collision would have a net positive or a net negative electrical charge.
Regarding black holes that are rotating, the testing of the model with two colliding black holes that are rotating at just under C with the whole variety of possible rotational axes of relative orientation or a good representative sample thereof would be interesting. The collisions of two black holes as such with different masses would also be interesting to model.
Also of interest would be the modeling of two colliding black holes wherein one black hole would be traveling with a much higher gamma factor than the other, but wherein the spin of one or both of the black-holes would have a relativistic or highly relativistic velocity and wherein one black hole would have a mass greater than the other and/or wherein the colliding black holes would have the same momentum perhaps allowing all of their kinetic energy to be transformed into stationary center of mass frame products. A representative sample of relative spin orientations would also be interesting to consider.
Regarding electrically charged black-holes, the modeling of the collision of two or more of such black-holes simultaneously wherein the net electrical charge of the system is zero, positive, or negative would be interesting to consider. Also, the collision of rapidly rotating black holes that are electrically charged, perhaps with rotation speeds just under C, and wherein the full range of relative axes of orientations or a representative sample thereof is considered, would be interesting to model.
The collision of non-charged black holes rotating near C with non-charged backhoes rotating much less than C with the full range of spins, masses, gamma factors, spin orientations, and black hole rest masses, or a representative sample thereof, would be interesting to model. Such a system of multiple black holes wherein one or more or all of the black holes is(are) extremely positively charged, and/or where one or more of the black holes is(are) extremely negatively charged, and/or one or more of the black holes is mildly charged would also be interesting to model; once again, with consideration of the full range of relative spin orientation combinations, translational gamma factors, spin velocities, and black hole rest masses. Also of interest would be to model the collision of a set of multiple (2 or more) such black holes (with all of the above parameter variations being tested) except for the case where any of the colliding black-holes would be charged.
Perhaps the testing of the full range of the above variables or a representative sample thereof can be performed wherein an attempt to excite resonant oscillatory modes within the black hole formed by the collision of the two or more black holes can be made. Such oscillatory modes might be brought to such a high amplitude such that the black hole shatters in a manner analogous to the failure of a piece of machinery under amplified vibrations of the machines natural oscillatory frequency modes.
The excitation of black hole oscillatory modes required to shatter a black hole might be produced through sequential collisions of more than two black holes in stead of simultaneous collisions of more than two black holes.
Note that by testing the full range of variables described above and any un-mentioned variables might permit the study of any symmetries or asymmetries in the structure of general relativistic space-time, or perhaps even such as might be the consequence of String Theory, The Theory of Branes, M-Theory, Loop Quantum Gravity, and/or Lattice Quantum Gravity.
Also, the testing of black holes made at least in part from matter and/or energy in the form of particles of the proposed yet to be discovered forms according to the theory of Supersymmetry may be relevant here also. It has been stated that black holes can only be defined by their mass, spin, and electrical charge, however, perhaps the electrical charge and electrodynamic field Supersymmetry analogues of the photino and the squarks and sleptons play a role here as well. Assuming that black-holes might have or be capable of super-symmetric hair, the super-symmetric analogues of electrical charge and associated fields might also be tested for the full range of collisional behaviors as described above.
Unlike of belief in God Creator that is belief in Thief.
There are no "black holes" in our universe, there is no constancy of light speed, there is no relativism.
My explanations are in http://bourabai.kz/catechesis.html
Karim Khaidarov, physicist http://bourabai.kz/index.html
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