Starship Asterisk*

ckam wrote:orin, zero cant be longer than another zero.

orin stepanek wrote:If you were traveling to a star system at the speed of light in the same direction that the universe is moving and returned at the same speed; would the trip there be longer than the return trip, or would the travel time remain the same? Why?
Orin

harry wrote:Hello All

I thought the only thing that can go faster than light is the propagation of gravity.

Abstract. Standard experimental techniques exist to determine the propagation speed of forces. When we apply these techniques to gravity, they all yield propagation speeds too great to measure, substantially faster than lightspeed. This is because gravity, in contrast to light, has no detectable aberration or propagation delay for its action, even for cases (such as binary pulsars) where sources of gravity accelerate significantly during the light time from source to target. By contrast, the finite propagation speed of light causes radiation pressure forces to have a non-radial component causing orbits to decay (the “Poynting-Robertson effect”); but gravity has no counterpart force proportional to to first order. General relativity (GR) explains these features by suggesting that gravitation (unlike electromagnetic forces) is a pure geometric effect of curved space-time, not a force of nature that propagates. Gravitational radiation, which surely does propagate at lightspeed but is a fifth order effect in , is too small to play a role in explaining this difference in behavior between gravity and ordinary forces of nature. Problems with the causality principle also exist for GR in this connection, such as explaining how the external fields between binary black holes manage to continually update without benefit of communication with the masses hidden behind event horizons. These causality problems would be solved without any change to the mathematical formalism of GR, but only to its interpretation, if gravity is once again taken to be a propagating force of nature in flat space-time with the propagation speed indicated by observational evidence and experiments: not less than 2x1010 c. Such a change of perspective requires no change in the assumed character of gravitational radiation or its lightspeed propagation. Although faster-than-light force propagation speeds do violate Einstein special relativity (SR), they are in accord with Lorentzian relativity, which has never been experimentally distinguished from SR—at least, not in favor of SR. Indeed, far from upsetting much of current physics, the main changes induced by this new perspective are beneficial to areas where physics has been struggling, such as explaining experimental evidence for non-locality in quantum physics, the dark matter issue in cosmology, and the possible unification of forces. Recognition of a faster-than-lightspeed propagation of gravity, as indicated by all existing experimental evidence, may be the key to taking conventional physics to the next plateau.

Abstract. Gravity has no aberration, and propagation delays cannot be used without destroying angular momentum conservation at an unacceptable rate. Even the curved spacetime explanation (“gravity is just geometry”) breaks down when masses and speeds are large, as in binary pulsars. But if gravity or spacetime curvature information is carried by classical propagating particles or waves, a modern Laplace experiment places a lower limit on their speed of 1010 c. The so-called Lorentzian modification of special relativity permits such speeds without need of tachyons. But there are other consequences. If ordinary gravity is carried by particles with finite collision cross-section, such collisions would progressively diminish its inverse square character. Gravity would gradually convert to inverse linear behavior on the largest scales. Curiously, at all scales greater than about 2 kiloparsecs, gravity can be modeled without need for dark matter by an inverse linear law. The orbital motions of Mercury and Earth may also show traces of this effect. Moreover, if gravity were carried by particles, a collapsed ultra-dense mass between two bodies could shield each of them from the gravity of the other. Anomalies are seen in the motions of certain artificial Earth satellites during eclipse seasons that behave like shielding of the Sun’s gravity. Certain types of radiation pressure might cause a similar behavior, but require far more free parameters to model. Each of these effects of particle-gravity models has the potential to lead to a breakthrough in our post-Einsteinian understanding of gravitation. This would also change our views of the nature of time in relativity theory.

In September 2002, two US scientists made some very accurate measurements of the position of a quasar as it passed behind Jupiter. They argued that the exact amount of apparent motion of the quasar (as the path of the radio waves from it was bent in Jupiter's gravitational field) depended on both the speed of light AND the speed of gravity. The measurements they took then proved that the speed of gravity is the same as that of light, ruling out some of the more bizarre modifications to the laws of gravity which have been proposed, and further backing General Relativity (BBC news article on the experiment).

Ed Fomalont of the National Radio Astronomy Observatory in Charlottesville, Virginia, and Sergei Kopeikin of the University of Missouri in Columbia made the measurement, with the help of the planet Jupiter.

"We became the first two people to know the speed of gravity, one of the fundamental constants of nature," the scientists say, in an article in New Scientist print edition. One important consequence of the result is that it places constraints on theories of "brane worlds", which suggest the Universe has more spatial dimensions than the familiar three.

But the assumption of light-speed gravity has come under pressure from brane world theories, which suggest there are extra spatial dimensions rolled up very small. Gravity could take a short cut through these extra dimensions and so appear to travel faster than the speed of light - without violating the equations of general relativity.

Electric signals can be transmitted at least four times faster than the speed of light using only basic equipment that would be found in virtually any college science department.

Scientists have sent light signals at faster-than-light speeds over the distances of a few metres for the last two decades - but only with the aid of complicated, expensive equipment. Now physicists at Middle Tennessee State University have broken that speed limit over distances of nearly 120 metres, using off-the-shelf equipment costing just $500.

but for the most part it is accepted that at some early energetic stage of the universe, the strong, weak and electro-magnetic forces were all unified and indistinguishable; the thought is that if you go back far enough, gravity is also unified with the others

harry wrote:Hello Orca
You are assuming that there is a start to all this and that the BBT is correct.

In my opinion, there was never a start and there will never be an end. Just a process of recycling and evolution of stages and phases of the objects within the universe.

But! you statement maybe correct within compact star cores and the so called Black holes as ultra dense plasma matter.

orin stepanek wrote:

ckam wrote:orin, zero cant be longer than another zero.

True! But how do you arrive at 0?

ckam wrote:

orin stepanek wrote:

ckam wrote:orin, zero cant be longer than another zero.

True! But how do you arrive at 0?

flying through space with c, you could arrive anywhere at no time (literally).

harry wrote:Mate, If you think that the Big Bang is it so be it. By next year the theory will be exposed. Its onlly a matter of time.

orin stepanek wrote:

ckam wrote:

orin stepanek wrote: True! But how do you arrive at 0?

flying through space with c, you could arrive anywhere at no time (literally).

Than if we had a machine [ship?] that could bend the space time continuum; [literally create our worm holes;] we could own the deepest reaches of the universe? But what would happen to the time everyone else lived in while we were [maybe weren't] gone? If that's true then the photons life across the universe is 0 time. Interesting!
Orin

harry wrote:One more point, many people think that the big bang started from one point. That is a mistake. If the the big Bang did occur it would have occured at the same time in many spots.

Actually, the Big Bang theory states that it happened everywhere at the same time. It's just that 'everywhere' happened to be much smaller at the time

It's just that 'everywhere' happened to be much smaller at the time

Qev wrote: There you go saying "just a theory" again. Everything in science that isn't an observation is a theory, and no theory can ever be proven, only supported or falsified.

harry wrote: The first part I garee with, but not the add on. What does smaller mean in an infnite universe.

harry wrote:Hello Orca

What logical traps?

The mind experiment went something like this: if you have an a static universe full of stars, gravity would, over time, cause them to come together. So the universe would end up with one big ball of stars. An infinite static universe would have an on-going cascade of such "star balls" constantly crashing together. So what if you had an infinite universe where you had an equal distribution of stars, so no one star was any more distant than another. Well, for one, the whole sky would appear white, as any line of sight would eventually fall onto the surface of a star. Another problem is that if any one star moved the slightest bit, you'd again have a difference in forces, and clumps of stars coming together.