Is lightspeed really a limit?

"We don’t (yet) have any way to test this, but University of Adelaide
applied mathematicians are suggesting that an extended version of
Einstein’s Theory of Special Relativity also holds true for
velocities
beyond lightspeed.

One of the main predictions of Special Relativity is that the speed
of
light is treated as an absolute cosmic speed limit, the line which
can
never be crossed; and even the notorious “faster-than-light neutrino”
incident in 2011 has left the theory intact as one of the most robust
in physics.

However, during the speculation that surrounded the neutrino
discussion last year1, the University of Adelaide’s Professor Jim Hill
and
Dr Barry Cox considered the question of how the mathematical
contradictions posed by a faster-than-light particle could be aligned
with
Special Relativity.

Their solution, which Professor Hill discussed with The Register,2
rested
on ignoring the speed of light’s status as an absolute limit, and
instead,
using the information where the relative velocity of two observers is
infinite.3."

See:

http://www.theregister.co.uk/2012/10...y_mathematics/

I haven't studied this to any great detail so I'll admit right up front
I could be missing something here, but the idea of an infinite speed
limit between two objects in motion relative to each other does appear
to be in conflict with the physics I was taught.

Mathematically you can postulate almost anything. In the real physical
universe, unless theory (well established theory, backed up by
experiment) is wrong, what I was taught is that two objects in motion
relative to each other will observe red-shift or blue-shift depending on
direction of travel (either away from or towards). The closer the delta
speed approaches 'c' the more severe the shift. To the point where very
near 'c' essentially the objects become invisible to each other due to
the shift. So even if there were an infinite speed allowable between
objects in motion, it is a useless postulate in the physical universe.

Dave

On 12-10-11 18:13 , David Spain wrote:
I haven't studied this to any great detail so I'll admit right up front
I could be missing something here, but the idea of an infinite speed
limit between two objects in motion relative to each other does appear
to be in conflict with the physics I was taught.

Mathematically you can postulate almost anything. In the real physical
universe, unless theory (well established theory, backed up by
experiment) is wrong, what I was taught is that two objects in motion
relative to each other will observe red-shift or blue-shift depending on
direction of travel (either away from or towards). The closer the delta
speed approaches 'c' the more severe the shift. To the point where very
near 'c' essentially the objects become invisible to each other due to
the shift.

Well, there seems to be no reason why such invisibility should be
impossible.

The explanation for the lightspeed limit that I was taught is that two
observers moving with a relative velocity larger than lightspeed could
disagree on the order of events that they both observe. This would mean
that while one observer would see that dropping an egg from your hand is
followed by the egg smashing on the floor, the other observer would see
the egg magically reassembling itself on the floor and then levitating
to meet your hand. Since special relativity postulates that all
observers are equivalent in that they see the same physics, including
causality, this would be a contradiction.

So far special (and general) relativity agree with observations (I'm
told) so there you are. But I'm not sure if this really proves that the
equivalence postulate is true, always and everywhere.

--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
. @ .

Niklas Holsti wrote:

The explanation for the lightspeed limit that I was taught is that two
observers moving with a relative velocity larger than lightspeed could
disagree on the order of events that they both observe.

There are two issues here that I am aware of.

For one take us as an observer between the two moving objects. The
transformations of Special Relativity say that I see both of them as
moving under (or over) C, but because the unverse is relative they also
see each other as moving under (or over) C. Unlike in General
Relativity, in Special Relativity there's nothing to say objects can't
go above C there's just no way to transistion from below to above and
vice versa. As photons can be made to decay into particles in principle
according to SR ignoring GR the process could create tachyons. That's
way the recent neutrino news was so interesting. The neutrinos were
newly created. Tachyons created at the big bang will have been beyond
the observable horizon long agao.

This would mean
that while one observer would see that dropping an egg from your hand is
followed by the egg smashing on the floor, the other observer would see
the egg magically reassembling itself on the floor and then levitating
to meet your hand. Since special relativity postulates that all
observers are equivalent in that they see the same physics, including
causality, this would be a contradiction.

http://www.theculture.org/rich/sharp...es/000089.html

That's a very long write up on FTL. It ends up with the conclusion that
either FTL is impossible or causality is wrong. But the examples that
break causality involve objects travelling near C communicating with
each other. I'm not worried about launching craft at 0.8 C looping back
towards Earth and telling us stuff.

So far special (and general) relativity agree with observations (I'm
told) so there you are. But I'm not sure if this really proves that the
equivalence postulate is true, always and everywhere.

So far. Time will tell if FTL is impossible or causality is wrong.
Maybe eventually.

On Oct 11, 8:13*am, David Spain wrote:
I haven't studied this to any great detail so I'll admit right up front
I could be missing something here, but the idea of an infinite speed
limit between two objects in motion relative to each other does appear
to be in conflict with the physics I was taught.

Mathematically you can postulate almost anything. In the real physical
universe, unless theory (well established theory, backed up by
experiment) is wrong, what I was taught is that two objects in motion
relative to each other will observe red-shift or blue-shift depending on
direction of travel (either away from or towards). The closer the delta
speed approaches 'c' the more severe the shift. To the point where very
near 'c' essentially the objects become invisible to each other due to
the shift. So even if there were an infinite speed allowable between
objects in motion, it is a useless postulate in the physical universe.

Dave

But perhaps not c+ invisible in the quantum entangled spectrum of
photons.

On Oct 11, 10:28*am, Doug Freyburger wrote:
Niklas Holsti wrote:

The explanation for the lightspeed limit that I was taught is that two
observers moving with a relative velocity larger than lightspeed could
disagree on the order of events that they both observe.

There are two issues here that I am aware of.

For one take us as an observer between the two moving objects. *The
transformations of Special Relativity say that I see both of them as
moving under (or over) C, but because the unverse is relative they also
see each other as moving under (or over) C. *Unlike in General
Relativity, in Special Relativity there's nothing to say objects can't
go above C there's just no way to transistion from below to above and
vice versa. *As photons can be made to decay into particles in principle
according to SR ignoring GR the process could create tachyons. *That's
way the recent neutrino news was so interesting. *The neutrinos were
newly created. *Tachyons created at the big bang will have been beyond
the observable horizon long agao.

This would mean
that while one observer would see that dropping an egg from your hand is
followed by the egg smashing on the floor, the other observer would see
the egg magically reassembling itself on the floor and then levitating
to meet your hand. Since special relativity postulates that all
observers are equivalent in that they see the same physics, including
causality, this would be a contradiction.

http://www.theculture.org/rich/sharp...es/000089.html

That's a very long write up on FTL. *It ends up with the conclusion that
either FTL is impossible or causality is wrong. *But the examples that
break causality involve objects travelling near C communicating with
each other. *I'm not worried about launching craft at 0.8 C looping back
towards Earth and telling us stuff.

So far special (and general) relativity agree with observations (I'm
told) so there you are. But I'm not sure if this really proves that the
equivalence postulate is true, always and everywhere.

So far. *Time will tell if FTL is impossible or causality is wrong.
Maybe eventually.

Quantum entangled photons might not care about the limit of +/- c.

: Brad Guth
: But perhaps not c+ invisible in the quantum entangled spectrum of
: photons.

Word salad that doesn't correspond to anything in reality.
How very convincing.

On Oct 11, 9:34*pm, (Wayne Throop) wrote:
: Brad Guth
: But perhaps not c+ invisible in the quantum entangled spectrum of
: photons.

Word salad that doesn't correspond to anything in reality.
How very convincing.

Are you suggesting that quantum entangled photons do not exist?

Why do we need to see or even detect entangled photons in order for
them to exist?

Are you suggesting that gravity is not quantum entangled?