My expectation is that wormhole travel is a thing better achieved by a
Kardashev 2 civilization. The grandchildren's work at intercepting a large
factor of the emitted solar photons. Oh, those crazy grandkids! The figure that
I sporadically arrive at is some 40-50 thousand years from now. Since I
imagine that to do miracles like a transverable wormhole, they are going to be
rather good at energy production, as well as other dream stuff.
Until then, we and our roboto descendant's have much cosmological research to
conduct. This will require a quite large budget.
Thx.
On Monday, January 17, 2022 Lawrence Crowell <everything-list@googlegroups.com>
wrote:
Sabine Hossenfelder's video is about the warp drive, based on the Alcubierre
warp solution of the Einstein field equations. Her conclusions are more or less
on the mark I think. A sub-luminal (slower than light) warp drive could work.
Even with negative mass-energy if the moduli for these fields is compact the
vacuum could be stable. However, if it reaches the speed of light there occur
horizons in the warp bubble that would disrupt it by preventing causal
communications through it.
The main investigator of this report of a possible warp bubble is Harold White,
who has a history of being a bit "out there" on things. Healso advanced the
so-called EM drive last decade which was found to not work.Why anyone though
that would work is beyond me. White has been a big exponentof the Alcubierre
warp drive. To be fair though, this claimed result, isjust a calculation of an
energy spectra of the Casimir effect comparable to what a warp bubble would
give, is how KipThorne proposes to generate wormholes. Wormholes and warp
drives share the sameenergy feature with T^{00} < 0, for for a source that is a
quantum field 〈0|T^{00}|0〉 < 0.
https://bigthink.com/starts-with-a-bang/no-warp-bubble/
The Casimir vacuumprovides the energy conditions required for the warp drive.
The negative vacuumcan be a source for hyperbolic geometry for exotic
structures such as wormholesand warp drives. This experiment employed the
Casimir vacuum and came up withresults that appear suggestive of a warp bubble.
This does not though mean wehave conclusive evidence of one. There are some
other reasons to maintain askeptical perspective on this.
The Alcubierre warpbubble is probably only stable for sub-light speed. If it
is set above thespeed of light it has particle horizons that causally separate
the bubble. Thismeans it is not stable, for Unruh-like radiation occurs.
This may lead to deepquestions. for the vacuum energy is related to the moduli
of curves, such as inthe Poincare disk and half-plane, and this is also in some
ways related to themoduli of gauge symmetry. Each curve bounds a region,
thinking in 2-dimensions,and this region is associated with entropy and
curvature. For this to work thevacuum has to be stable, which means it is
Virasoro or CFT_2 or more. I thinkthis imposes this limit on the warp bubble as
being sub-light speed.
This warp bubble mightexist, and for various reasons it would be a fascinating
development for thefoundations of physics. This is not to say I think we will
be using this forspaceships, at least not at all soon. These DARPA results are
suggestive, but actual experiments will have to rise to what might be called
the 5-σ level. Iam rather skeptical of this however, even though if this is
real it would pavethe way for a major probe of the quantum vacuum.
As for fusion, just getting a fusion powerplant is a big hurdle to jump. The
Chinese have made an announcement of a fusion device that sustained 15 million
K temperatures for 100 or a 1000 second. I cannot remember which. This has a
long way to go, and as the joke goes, 20 years from now fusion power will still
be 20 years in the future. As for a space power or propulsion, that is far out.
We still do not have fission powered space systems or propulsion, and fusion
will be far more difficult. The Chinese system is fairly large and the ITER
program involves a really large reactor. Space based systems need to be small
and as low mass as possible.
LC
On Saturday, January 15, 2022 at 10:55:58 PM UTC-6 spudb...@aol.com wrote:
So earlier today I watched Sabine hassenfelder the physicist from Germany
indicate that any kind of wormhole travel or FTL is strictly unlikely. What I'd
like to ask is, whether all the work that's done today for creating commercial
nuclear fusion is more or less likely, than using the same technology to
develop fusion plasma rockets to travel much more swiftly within the solar
system? Our fusion plasma rockets the lower hanging fruit, versus commercial
nuclear fusion? Thanks!
On Saturday, January 15, 2022 Lawrence Crowell <everyth...@googlegroups.com>
wrote:
It is possible for a binary starsystem to interact with a third star so there
is an exchange. We do normally expect binary star systems tohave similarly
oriented angular momenta.
This is an interesting result. To computethis would have been tough. This is a
case of a Robinson-Trautman twisting solutionor a twisting type N. The addition
of the two angular momenta results in theoccurrence of angular momenta
perpendicular to the initial angular momenta.This can be seen in with the
classical group [L_i, L_j] = ε_{ijk}|L|^2 n_k, forn_k a unit vector. This means
there is the emission of angular momentum in thegravitational radiation. The
calculation was most likely done numerically.
LC
On Thursday, January 13, 2022 at 1:13:02 PM UTC-6 johnk...@gmail.com wrote:
On Thu, Jan 13, 2022 at 1:37 PM Brent Meeker <meeke...@gmail.com> wrote:
> Kudos to whomever did the calculation for this. But I would have thought
that most collisions would be misaligned in both spin axes and impact plane.
The Sun's spin axis isn't aligned with the Milky Way's axis of rotation, so I
had assumed most stars have randomly directed spin axes.
Stars do have random axis of rotations in general but not if you're talking
about double stars, and the sun is rather unusual in being only a single star,
most stars are double stars, and they were created at the same time from the
same rotating cloud of gas and dust and thus have similar axis of rotation, so
when the resulting stars turned into Black Holes they would also have similar
axes. And indeed most of the Black Hole mergers so far detected by
gravitational waves have been of that sort, but not this one, that's what makes
it so unusual. This system must've been formed by two stars that formed at
different places at different times but then got close together and somehow
went into orbit around each other.
John K Clark See what's on my new list at Extropolisqbj
Brent
On 1/13/2022 3:49 AM, John Clark wrote:
For the first time a sort of gravitational wave rocket has been found. By
re-examining the data from the LIGO and Virgo gravitational wave observatories
researchers report on January 6 they have detected the merger of 34 and 29
solar mass Black Holes that resulted in a Black Hole of about 62 solar masses
with about one solar mass being converted into gravitational waves. What makes
this merger unusual is that it was not symmetrical, the axis of spin of the 2
black holes were not aligned with each other and neither was aligned with the
axis of orbit around each other. This would indicate that the 2 stars that form
them (assuming these 2 large Black Holes were actually formed from the corpses
of dead stars) were not born in an isolated system but probably came from a
denser environment like a globular cluster. Even more interesting is that the
misalignment of the spins means that the gravitational waves emitted were not
emitted symmetrically, and gravitational waves carry some linear momentum. So
the resulting 62 Solar mass Black Hole must've received a pretty substantial
kick causing it to move pretty fast, and that's just what the researchers
found, because of that kick the huge 62 solar mass Black Hole started moving at
least 700 km a second and probably closer to 1500. It's probably moving fast
enough to escape whatever galaxy it was in.
Evidence of large recoil velocity from a black hole merger signal
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