This is what blows my mind, if only I'm correct that is. James Clerk Maxwell, a Scottish scientist, reportedly derived the speed of electromagnetic radiation and when his cross-Atlantic colleagues measured the speed of light (c), they found out that, this is where it gets interesting, c = the speed of electromagnetic waves. This led to the obvious conclusion that light was an electromagnetic wave!

Faster than light travel?

Have a look at this :point: Time Lag Argument For Idealism @Bartricks

According to Bartricks' the perceived present moment hasta be the true present moment (light should possess infinite speed or light is an illusion, thereabouts) and ergo, he argues, materialism (limited by the finite speed of light) is false.

I tried to run this by a physics forum but they aren't keen on hypotheticals and thought experiments. — TiredThinker

You need a physics forum that allows speculations. A philosophy site isn't really going to have a lot of members that know their physics.

How close to light speed could this ship go? — TiredThinker

Same speed limit as one that carries its fuel with it, except a lot more efficiently.

A light-sail sort of works this way, with the energy supplied remotely by a 'stationary' source, thus giving hypothetical indefinite thrust. Relative to a local inertial frame, nothing can go as fast as c, but it can get arbitrarily close.
A rail gun is also far more efficient than a rocket, and doesn't require this illegal fuel transfer you suggest.

But one doesn't need the fancy scenario either. Relative to say some muon in the upper atmosphere, I move at nearly light speed, else I'd not be able to reach it before it decayed. No rocket required, which is only needed to change velocity, not to already be at some arbitrary velocity.

Another way of getting around it: Don't use an inertial frame to do your measurements. For instance, relative to the cosmic frame, and per Hubble's law, a galaxy 20 billion light years away is receding from us at around 1.3c (again without benefit of rockets), so all you have to do is be far from something to be moving faster than c relative to it (using cosmological coordinates, not inertial coordinates).

There are other ways to go at a least a bit faster than c utilizing gravitational potential and such, another thing which goes beyond the inertial limits of special relativity.

they found out that, this is where it gets interesting, c = the speed of electromagnetic waves. This led to the obvious conclusion that light was an electromagnetic wave! — Agent Smith

Happens to be that EM waves are light, but it doesn't necessarily follow from the evidence. Gravitational waves also travel locally at c, and yet they're not light.

How did Maxwell measure this speed? It's not like he could sync clocks on different continents. Sagnac effect says that in the frame of Earth's surface, westbound light is faster than eastbound light, such that light sent one way through a fiber optic cable around the world will arrive back at the source at a different time than light sent the other way. This doesn't violate relativity since a non-inertial frame was used to take the measurements.

How close to light speed could this ship go? — TiredThinker

The short answer is that it can go arbitrarily close the speed of light without ever reaching the speed of light. With more fuel magically available it can increase it's momentum indefinitely, getting closer and closer to the speed of light (from our perspective on earth).

Long answer, the ship will always measure the speed of light as C on the ship, so relative the ship's frame of reference it stays stationary relative the speed of light (its motion relative to us on earth changes, but the speed of light stays constant for all observers, so the ship never measures the speed of light different).

Or perhaps it would eventually convert into energy ceasing to be the ship in order to travel at light speed? — TiredThinker

This would not occur. Only massless particles can travel at the speed of light (and no other speed). Particles with mass travel can get arbitrarily close but never reach the speed of light.

As points out, cosmic rays can go incredibly close to the speed of light, and are a good example of your external energy experiment (energy being supplied to the particle by a quasar or super nova).

Some particles hit our atmosphere with the kinetic energy of a major league baseball pitch, which I find pretty incredible a single particle would have the impact of a 90 mile an hour fast ball (if all the energy could be dumped in a catcher's mitt).

The thing difficult to wrap one's head around is the speed of light being constant for all observers regardless of their relative motion, but there's plenty of youtube videos that explain it in different ways.

The more philosophical aspect of it is that such a principle means the universe has no preferred reference frame, and there's no logical reason for that to be the case (entirely possible to imagine a universe that clearly has a "standing still" frame of reference with some observable effects simply for not being still, with larger effects the less still you are). This no-preferred reference frame (and thus speed of light is the same for all observers), fits in with a series of philosophical / seemingly observed assumptions about cosmology, such as there is no centre to the universe (universe is similar in all directions on large scales), no special time (in the sense of recording events), the laws of physics are the same in the whole universe through both space and time, particles are identical and have no unique identities, and a few others.

Even something as fundamental as the electric and magnetic fields aren't special, what is a magnetic effect from one perspective can be an electric effect from a different perspective. Likewise a gravitational field can be indistinguishable from acceleration.

There's a sort of theme to these "no special reference point" and "no-special place" and "no-special particles" and "no-special laws" and "no special time" set of principles. There's no "logical" reason that this needs to be the case.

As puzzling as these nothing-special principles are, is that there are exceptions to the theme in that there's a special direction to entropy (increases rather than decreases) and special moments in time (beginning of the universe as well as the present moment ... again, just as there's no logical necessity to the first nothing-special principles, there's no logical necessity to either a beginning in time nor consciousness perceiving one moment in time, rather than all time at once or then going backwards or forwards with no particular preference or even just jumping around randomly through time). Non-unique, uniform types of particles (although the kinds of particles are a special quantity for no particular reason), combine to form unique objects with tractable histories. Your consciousness is also special to your body ... again, not really any reason for that when you think about it.

Only sci fi offers solutions to interstellar or intergalactic travel. Wormholes/space warping(folding),subspace/hyperspace/stargates etc.
We are on our way to meeting up with the stars and planets of the Andromeda Galaxy. Perhaps at the end of that event we will have some newbies, moved in, close by!
Carl Sagan seemed to feel that the wormhole idea was the most plausible for his book/movie Contact.
I have always trusted Carl's ideas.

I think we could get to Proxima and Barnard's star etc by making 'stepping stone stations' along the way.
Might take a while though!

Ok. How do we know that light can only travel at exactly 1 speed? Massful things can vary in speed. How can light have only 1 speed? Perhaps light that exceeds our measure of "lightspeed" can't be measured in the massful world. Basically only light's lowest energy state represented here?

How do we know that light can only travel at exactly 1 speed? — TiredThinker

It doesn't. It depends on the medium through which it travels. It can be made to creep very slowly indeed in the laboratory.

It doesn't. It depends on the medium through which it travels. It can be made to creep very slowly indeed in the laboratory. — jgill

:rofl:

Happens to be that EM waves are light, but it doesn't necessarily follow from the evidence. Gravitational waves also travel locally at c, and yet they're not light.

How did Maxwell measure this speed? It's not like he could sync clocks on different continents. Sagnac effect says that in the frame of Earth's surface, westbound light is faster than eastbound light, such that light sent one way through a fiber optic cable around the world will arrive back at the source at a different time than light sent the other way. This doesn't violate relativity since a non-inertial frame was used to take the measurements. — noAxioms

Danke!

Please tell me why it's speed of light and not velocity of light? A laser can be pointed in a particular direction, oui?

Please tell me why it's speed of light and not velocity of light — Agent Smith

c is a scalar, the so called speed of light, which, given the postulates of relativity, is constant regardless of inertial frame.
Velocity is a vector, and the vector of light is not constant, and is frame dependent.
The same pulse of light might be in the +x direction in one inertial frame and +y in another, and yes, a laser can be pointed in any direction.

Why you ask? I didn't mention velocity at all in the part you quoted.

Ok. How do we know that light can only travel at exactly 1 speed? — TiredThinker

We don't know it. Theory of relativity lists that merely as an assumption (2nd premise of SR). All we know empirically is that the round trip speed of light will be measured to be c in any inertial frame. That doesn't mean it necessarily doesn't have a different speed in +x direction than it does in -x direction. Einstein's theory assumes this, but other theories don't. I know of no theory that doesn't that derived its own generalization of the theory.

Basically only light's lowest energy state represented here?

Light moves at the same speed regardless of energy. Energy of light is frame dependent just like its direction. Lower energy light will be of lower frequency and longer wavelength.
These things being frame dependent isn't new. Energy isn't absolute. Kinetic energy is also frame dependent, and any given solid non-rotating object has zero kinetic energy in its own frame.

Astronomical radio telescopes have to be pointed at a source which means radio waves have direction (vector, not scalar) and light belonging to the same family as radio waves should be vector too? We can't see around corners. :chin:

Light moves slower than your minivan

:rofl:

I feel like an hourglass - old, very old indeed! New state of matter!!! Caramaba!

received its fuel through a magical portal — TiredThinker

Strange thing that your physicists did not welcome your idea about "magical portals"! :grin:

Strange thing that your physicists did not welcome your idea about "magical portals"! — Alkis Piskas

I accepted it because the magic wasn't essential to the point asked by the OP.
One could just put fuel tanks en-route and at speed, waiting for the rocket. The rocket goes out at 10g, runs out of fuel, and there just happens to already be a tank sitting there with matched speed. The rocket refuels, continues on, and just keeps doing that. No magic required, and it doesn't violate any physics to have all these high-speed tanks at just the right spot each time. It's just an engineering problem.

Point is, (as an answer to @TiredThinker ), the rocket is never going to go faster than c relative to say the frame where it was originally stationary no matter how long it keeps doing that.

Astronomical radio telescopes have to be pointed at a source which means radio waves have direction (vector, not scalar) and light belonging to the same family as radio waves should be vector too? — Agent Smith

I never said that vectors could not be used to describe EM waves.
I'm really trying to figure out the relevance of your comment, but cannot.

I said that the local speed of light in a vacuum is constant (c), but that the local velocity of light is not since yes, it can go in any direction. Furthermore, the speed of a specific local pulse of light in said vacuum is always c in any inertial frame, but the velocity of that same pulse of light is frame dependent.

Speed of light is not c necessarily c in non-inertial frames. For example, in the frame of Paris, light near say Neptune might actually come to a stop, and then turn around and go back the way it came for a while. That's because Paris isn't inertial.

We can't see around corners.

Not in flat space, but space isn't flat, and JWST has some very nice pictures that very much show it seeing around corners.

I got it! Danke!

I tried to run this by a physics forum but they aren't keen on hypotheticals and thought experiments.

What if we had a space ship that received its fuel through a magical portal that goes to a large tank on earth that is stationary. The portal on the ship moves with the ship and continues to fuel the engines. Neither the fuel or the tank on earth count as part of the ships' mass. Lets even say the fuel mass is many times greater than the ship it propels as it goes faster and faster. How close to light speed could this ship go? Or perhaps it would eventually convert into energy ceasing to be the ship in order to travel at light speed? — TiredThinker

Take it as a compliment. Imaginative thinking is not the strength of most physics forums. Not only is your idea interesting but it is sound without the need for any magic. In planetary missions the gravitational force of the planets has been used to speed up and to redirect planetary probes to their next target. For your rocket, the portal can be substituted for by black holes and neutron stars which are plentiful and can be used indefinitely to propel your rocket, though the trip might take hundreds of million years. Just don't get too close to any of the black holes or stars or the rocket will revert into pure energy.

After reading your hypothesis the first question that came to my mind was : "Why is he putting the propulsion energy off of the ship?" You didn't really answer that question. Then I came to my own conclusion which was that : Any energy that we were using, would have to be made of energy no greater than c, given the axiom that no thing can travel past the energy/speed of light. This axiom comes into question itself given that g is greater than c, inside the boundaries of black holes. They themselves aren't massless (as we figure) but somehow attract faster than light (which is maseless). A small inconistency there. I venture to think of energy moving past the speed of light often. I wonder if you can develop your hypothesis more here, to add onto what is meant by "having a energy source some where else" and "how that effects the energy of ship, in what ways (that is)." I'd be happy to address my thoughts on FTLS more, but don't feel stimulated to do so as of now. @TiredThinker

I accepted it because the magic wasn't essential to the point asked by the OP. — noAxioms

Well, it isn't just the word "magic". It's its combination with the word "portal" that creates the whole effect. I don't know, maybe @TiredThinker should have presented the subject rather in a Sci-fi Convention. I believe it would have received a warm welcome! :grin:
(OK, enough with this joke; it was good while it lasted! As for Physics, it's not my cup of tea.)