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Given matter-energy equivalence, matter cannot travel at c, so how can energy(light) travel at c?

In other words, light shouldn't travel at the speed of light.

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  • Asked by jiwasiw
  • on 2011-03-03 11:39:56
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Categories: Our universe.

Tags: cosmology, Speed-Of-Light, Universalweirdness.

 

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How do we know that the universe is isotropic and not, for example, fractal in its structure?

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Categories: Our universe.

Tags: physics, cosmology.

 

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When cosmologists talk of the early universe, what yardstick do they use to measure time?

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Categories: Our universe.

Tags: physics, cosmology.

 

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Does the whole universe have spin?

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Categories: Our universe.

Tags: physics, cosmology.

 

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from where the universes of multiverse get energy to float, collide & expand?

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  • Asked by sandeep
  • on 2010-11-29 11:13:53
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Last edited on: 2010-11-30 08:21:14

Categories: Our universe.

Tags: Space, Universe, cosmology, Stringtheory, m-theory, multiverse.

 

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How do we know the true shape of Galaxies?

This one's making my brain hurt.

Given the enormity of galactic bodies, doesn't it follow that (unless we're lucky enough to regard a galaxy at an exact right angle to its plane of rotation) the light from its more distant edge has taken aeons longer to reach us than that from its nearer edge?

Consequently, doesn't it follow that the "flat" images our telescopes are seeing are hopelessly distorted versions of what's really there?

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Categories: Our universe.

Tags: cosmology, Galaxy, telescope, observablelight.

 

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How does Hawking Radiation transmit negative mass to a singularity?

If you define an arbitrary plane in free space, then the mass, momentum, and energy of virtual particles crossing the surface will balance (statistically over a given time period). If this plane is parallel to and very close to an event horizon, then an imbalance occurs as some of the virtual particles are lost to the event horizon, making re-combination impossible and thus creating a surplus. The net surplus at the other side of the surface in terms of the mass, momentum and energy of the orphaned particles is then balanced by the mass, momentum and energy of the particles that strayed far enough from the original plane to cross the nearby event horizon. This implies that if an event horizon occurs, it will leak energy (mass and momentum from orphaned virtual particles) into the "real particle" universe.

 

My problem is that this model leaks from the "vacuum energy", and creates Hawking Radiation in equal, statistically interchangeable, forms on both sides of the gap between the arbitrary plane, and the event horizon. Everything you loose on one side, you have therefore gained, as an orphan, on the other. You get opposite charge, but still the same individual mass and overall momentum. So the total vacuum energy erodes (very slowly) but the black hole expands (also very slowly).

 

Even if you invoke negative energy particles, they are either repelled by the gravitational field (making things much worse) or at best they cancel the in-falling Hawking Radiation, and produce some very strange external emissions, but no net loss of mass from the black hole. I can’t create a bias, as it implies a bias in free space. Besides, I can’t tell in advance which virtual pairs will become separated, or which individuals orphaned, so there is no biasing mechanism available.

 

If this was the case then black holes would remain stable. Can someone please explain what is missing from this model? How does it differ from the accepted model of Hawking Radiation and the decay of Black Holes?

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  • Asked by mcquillp
  • on 2010-07-08 18:46:00
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Categories: Our universe.

Tags: ouruniverse, relativity, blackhole, cosmology, quantum, Event-horizon, casimir, vacuumenergy, QED, HawkingRadiation.

 

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Do we know exactly where the Big Bang took place?

Directly after the Big Bang, all matter began expanding in all directions and is still doing so.  Therefore, if we "roll back" time and watch everything return to where it originated, that would be the point where the Big Bang took place.

Do scientists know where that is?  That would be the center of the universe, correct?

 

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  • Asked by Robcon
  • on 2010-02-26 01:46:13
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Categories: Our universe.

Tags: ouruniverse, cosmology.

 

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The real question

 

What the meaning of life the universe and every thing and not 42.

 

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Categories: Our universe.

Tags: Universe, cosmology, 42, meaningoflife.

 

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Why does everything spin

From the smallest particle to the largest galaxy, and maybe even the universe itself, everything seems to be in a spin. What causes this spinning? Is it fundamental result of physical laws? How did it start? Can it be stopped?

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  • Asked by alandix
  • on 2009-11-23 19:43:51
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Categories: Our universe.

Tags: physics, Universe, cosmology, ParticlePhysics, spin.

 

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