How else would you measure the velocity of a spacecraft?

Yes, the speed of light in a vacuum is constant for all observers, independently of the relative velocity of the emitter and observer, but the velocity of a spacecraft is measured relative to a particular inertial reference frame, not light itself.

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Conscious reasoning is an attempt to justify the choice after it has been made.

Call me foolishly optimistic, but I chose, 'maybe in a thousand years'. Sure, our present day understanding of physics say, ' No way, uh uh, end of story.' But our present day physics of just a century and a half ago said 'Splitting the atom? No way, uh uh, end of story.'
That isn't a long time.
So, I still hope, rationally or not, we find a way to explore the utter depths of the sky, falling deep into infinities heart.

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It depends what you mean by faster than light.

There are lots of supposed ways to traverse space-time from point a to point b faster than light can travel from point a to b through just pure velocity.

For example, Worm holes. You don't go faster than light, you just don't travel through the space between point a and b.

Or Warp where you create a bubble of space where the space around you is contracted and expanded around that bubble allowing you to move from a to b faster than light.

Or Hyper-dimensional where you travel into a higher dimension of space time which makes the points a and b closer together.

I mean, do you mean, can someone ever accelerate their mass through normal space-time beyod the speed of light OR do you mean can you reach point b from point a quicker than light?

The OP question was "Is faster than light travel possible?". This implies exceeding the speed of light as a velocity. Wormhole shortcuts, etc, were later mentioned, but the poll also didn't imply this interpretation.

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Conscious reasoning is an attempt to justify the choice after it has been made.

Yes, but which reference frame. It's arbitrary.

Not if the spacecraft was launched from Earth. That would be a very good reason for choosing a local reference frame.

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Conscious reasoning is an attempt to justify the choice after it has been made.

I miss the poll option "Yes, take me to your leader!"

kidding.. don't change the poll after 3 pages

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin
"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
Meet the OOONG TOE.

That's always implied.

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Conscious reasoning is an attempt to justify the choice after it has been made.

A couple of hundred years ago most scientists would have said it is totally impossible to have a little gadget that would allow you to sit in Central Park (or most places) and talk to friend in Hyde Park (or most places). And it only costs a few cents a minute.

I am sure there will be lots of new discoveries in Physics that we cannot now even imagine.

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/onyE

Really? What physical law would they have referred to which disallowed it?

There's a world of difference between not knowing how to do something, and having a pretty well established physical law that seems to preclude it.

Very well put. And such a common misconception, too. It's almost as if you can imagine them picturing some angry red faced scientist blustering, "Impossible! Why the idea is preposterous!"

People been watching too many movies, methinks...

Other common misconceptions are that A few hundred years ago, scientists claimed that Powered flight was impossible and that we couldn't go faster than 65mph. Totally false. In fact, scientists postulated about flight thousands of years ago, including Heron of Alexandria.

Another is that a few hundred years ago scientists thought the Earth was flat. Eratosthenes would be surprised at this news.

I've been paying attention to Kurzweil's ideas for quite a while. But even if we (including cybernetic enhancements) become extremely intellectually competent, we can't make the impossible happen. We can't add new whole numbers between one and ten. We can't substantially increase the chemical energy released by oxidizing octane. I think the reasons that we can't travel faster than c might become better understood, but they probably won't change.

I expect that the "singularity" will lead us to being able to handle the complexity of nano-technology and molecular biology... and possibly advances in sociology and government. Great stuff, but it won't make the physically impossible possible.

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Forming opinions as we speak

That's not how I perceive it, anyway, what isn't in dispute is that for orbit calculations to be correct the effect of gravity needs to be input as instantaneous. Osbservation and experimentation confirms this without any doubt.

In Newton's day, you would not find any argument. However, Newton's theory of gravity has been found to be not quite right. Observation and experimentation confirms this without any doubt.

The speed of gravity can be calculated from observations of the orbital decay rate of binary pulsars PSR 1913+16 and PSR B1534+12. The orbits of these pulsars around each other is decaying due to loss of energy in the form of gravitational radiation. The rate of this energy loss ("gravitational damping") can be measured, and since it depends on the speed of gravity, comparing the measured values to theory shows that the speed of gravity is equal to the speed of light to within 1%.

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Everyone is entitled to his own opinion, but not his own facts.

And the interpretation of the result was disputed. The observations & experiments I am talking about are orbit calculations that require gravity to propogate instantaneously. These are proven to be correct as they are also applied to satellites, probes etc.

EDIT - Sorry wrong experiment although the one you mention has an important caveat;

"However, measuring the speed of gravity by comparing theoretical results with experimental results will depend on the theory; use of a theory other than that of general relativity could in principle show a different speed, although the existence of gravitational damping at all implies that the speed cannot be infinite."

Until there is independent and undisputed proof that the speed of gravity is c then I am sure scientists and engineers will continue to use instant propagation speeds in their formula (actually I'm sure they will continue with those formula whatever happens regarding the speed of light proof).

Hey, just trying to clue you in, Webbo. If you insist on staying clued out, well, that's your choice.

That's not how Nature does it.

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Everyone is entitled to his own opinion, but not his own facts.

How does it work then and how is this applied to orbit calculations?

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Forming opinions as we speak

I don't. It's calculated as instant by man. I was just interested in Nature's take on it. Where would I go to ask that?

I sure hope so! I'd love to imagine away around relativity's pain of a speed limit .. Some loophole with tachyons or warp drive or wormholes. Yes, I'm an Sf fan and might just be in an overly optimistic mood tonight but I do think we have to keep in mind Arthur C. Clarke's first (or was it second or third?) law :

If distinguished but elderly scientists say that something is possible then it probably is, if the same scientists say that something is impossible, they are very likely wrong! ;-)

Mind you, any such discovery does seem at least a hundred years off if not longer ... Although given any such development could potentially violate casuality (thus enable time travel) who knows!?

BTW. If I were granted one wish by the legendary fairy tale magic genie it would be to have my own faster than light starship and all it takes to fly it wherever I choose!

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I'd suggest doing so here on the BAUT but via starting a new thread dedicated to that question - are you able to start one? I'd imagine you should be ..

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I voted no. But as I understand it, it is possible to go anywhere as quickly as you like by traveling below the speed of light. The speed limit is only a problem if you plan on making a return trip, and expect to find things more or less as you left them.

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Principal Principle Offender

I know enough about the speed of gravity question to say that Webbo is
not entirely right, but he isn't entirely wrong, either. I don't know enough
about it to explain it. In vague terms, gravity is different from the electric
force in that when things interact gravitationally, their uniform motions are
in effect taken into account, so that it is almost as though each object
"knew" where the other object was at that instant, rather than at the
earlier time that would seem to be required by the light travel time delay.
When objects are accelerated by forces other than gravity, the difference
would theoretically become visible, and you would see that gravitational
force actually propagates at the speed of light, not instantaneously.
But that is a very difficult experimental situation to set up. In practical
situations, gravity looks as though it propagates instantaneously.

-- Jeff, in Minneapolis

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http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

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Brett
Peters Creek, Alaska
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There is quite a difference between traversable wormholes and the Alcubierre drive.

Wormholes represent a shortcut in space, so that different parts of the universe are connected by a shorter route; you travel through this shorter route, but you never exceed the speed of light.

The Alcubierre drive contracts the space in front of the ship and expands the space behind it, so that the ship remains motionless but travels towards its destination. Its speed relative to its start and end point is not constrained by the speed of light any more than the expansion of the universe is so constrained.

These are very different solutions to the same problem; but unfortunately both rely on something unobtainable in order to work their magic. That something is exotic energy; also known as negative energy, phantom energy, averaged null energy condition violating exotic mass-energy...

none of which are available in non-trivial amounts in the real world at the present. According to this Scientific American article by Lawrence Ford and Thomas Roman, exotic energy in non-trivial amounts might be forever out of our reach.
Warning, PDF file
http://www.phy.duke.edu/~hsg/55/rela...s-jan-2000.pdf

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That's ok, I'm happy to stick the real world answer that is used in application and calculations of the orbits of planets, probes, satellites etc. It's instant.

We perceive and understand the dimensions we live in, why? Because we can understand
them. If spacetime is a fabric, it must have structure, and that structure can allow for
faster than light speed, why? Because other dimensions are involved.
Nokton.

I have no idea what you just said.

I had a dream last night. I was travelling at 99.99999999% the speed of light through a vast vacuum when it happened. I entered a relatively dense pocket of gas. Suddenly, it felt as if I was travelling faster than light. I couldn't even see my exhaust plume anymore. Some guy Cerenkov told me I wasn't crazy either.

Does that count? hehe

That would have been a hot time...

I imagine it would have felt like sitting still and watching a cloud of gas come toward you at nearly the speed of light.

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Forming opinions as we speak