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[Starver]

You're misunderstanding I think. Both transmitter and receiver are sending their signals greater than c.

I know that, I was using the light flashes as references.  Which I think you missed.

And the only way a half-light-minute-away receiver gets the signal .5 minutes faster than it should have is if the signal is instantaneous.  At 2c, it's a quarter of a minute faster than expected.  The rest...  No, I don't get, unless tied in with this confusion.

[Bohandas]

...Why are people so eager to call science wrong anyway?

Wait, did you really ask that? We aren't talking about Religion here, we are talking about Science, whose fundamental process involves questioning EVERYTHING.
If someone is eager to call science wrong, it is likely because they are questioning things being "right". Seems to me that is keeping within the spirit of what science is all about. Sure this can be taken to extremes, but as long as the scientific method is used it's still science. I'm more concerned about people who are claiming that this doesn't need to be tested because "This can't be wrong, too much hard science proves it was right for too long!"

I'm not saying it is right, I'm just saying that you can't expect things not to be questioned.

Exactly. The purpose of science is not to open the door to infinite wisdom but to close the door to infinite folly.

[RedWarrior0]

Look, I'm not saying it was aliens...

But it was aliens.

Also, for those wondering, first of all gravity is also constrained to c, so, for example, if the sun just poofed away we would still orbit it until about 8.5 minutes later, when it goes dark.

Secondly, if you plot mass as a function of speed, superluminal objects have imaginary mass. I believe mass in motion is equal to rest mass divided by the square root of (1- (speed squared over c squared). So if a superluminal object just poofs into existance, it would have extremely large but imaginary mass. The wonky thing is, as the speed continues to increase, the mass actually decreases. An object at speed 2c has 1/3i of its rest mass and 4 c squared/9i times rest mass in energy. I don't feel like doing the math right now, but I feel like the derivative past speed = c is going to be close to or possibly even below 0.

[Montague]

Didn't they theorize neutrinos went FTL a long time ago? I know there are particle interactions that exceed the speed of light, anyways.

Neutrinos have always been weird particles anyways, they have virtually zero mass and they zip through Earth like it's not even there. About 65 billion solar neutrinos per second pass through every square centimeter perpendicular to the direction of the Sun in the region of the Earth.

With M-theory and all that, it's probably something that exists primarily in another dimension, like gravity. That or the people studying them are not reading their instrumentation correctly, or their instrumentation isn't working as intended.

[Virex]

...Why are people so eager to call science wrong anyway?

Wait, did you really ask that? We aren't talking about Religion here, we are talking about Science, whose fundamental process involves questioning EVERYTHING.
If someone is eager to call science wrong, it is likely because they are questioning things being "right". Seems to me that is keeping within the spirit of what science is all about. Sure this can be taken to extremes, but as long as the scientific method is used it's still science. I'm more concerned about people who are claiming that this doesn't need to be tested because "This can't be wrong, too much hard science proves it was right for too long!"

I'm not saying it is right, I'm just saying that you can't expect things not to be questioned.

You make a valid point, I should expect things to be questioned and I do. However, the scientific method relies on the formulation of hypotheses that are at least halfway coherent and to do that, one needs to go beyond the basal reaction of "Well maybe you're wrong, why can't you accept that". You know, that is an option we hadn't considered yet and that people don't bring up pretty much every time there is something sciency in the news. If you have an idea of what we should reject and what we should keep, and a rough idea as to how to test that, then please bring it up, but don't expect people to take a hypothesis such as "relativity is wrong" on face value because it's essentially as worthless as bringing your car to a car factory and telling the plant manager that it's making a strange noise.

[Zaerosz]

Um. Complete physics noob here (high-school almost-dropout), but couldn't any particle with less mass than a photon reach a speed higher than c with the same amount of energy? Using E=mc² and the average energy of a photon (found through Google) being 1.026 E-22 (4sf), I calculated the average mass of a photon to be 1.141036574 E-39. Is there any reason that anything with less mass couldn't travel at a higher velocity with the same amount of energy?

[Kogan Loloklam]

However, the scientific method relies on the formulation of hypotheses that are at least halfway coherent and to do that...

No, it does not. If it did, we wouldn't be where we are today.
A hypothesis needs to
1) Describe a mechanism in which observed phenomena function.
2) Be testable.

Those are the only real requirements for a hypothesis to be subjected to the Scientific Method. Coherency or distance from fringe are not required. In fact, most of the more revolutionary ideas are entirely on the Fringe and do throw out EVERYTHING. You know, like the fact the sun doesn't revolve around the earth after all? We take it for granted, but at one time that was throwing everything everyone knew and based information on out the window.

[MonkeyHead]

...

Um. Complete physics noob here (high-school almost-dropout), but couldn't any particle with less mass than a photon reach a speed higher than c with the same amount of energy? Using E=mc² and the average energy of a photon (found through Google) being 1.026 E-22 (4sf), I calculated the average mass of a photon to be 1.141036574 E-39. Is there any reason that anything with less mass couldn't travel at a higher velocity with the same amount of energy?

Yes, many. The main ones are covered by the theories of relativity. Basically very fast stuff doesnt act like stuff moving at "normal" speeds. High speeds have initially difficult to understand effects on mass (chiefly, as you approach c your mass increases), which has knock on effects on force/acceleration/energy...

I have some issues with the idea of an average photon energy (depends on wavelength/frequency... work done by Max Planck, E=hf), and also the concept of mass of a photon when they exists at c and hence relatavistic velocities, which as mentioned above plays tricks with mass. Also pretty sure than E=mc^2 wont yield the mass of a photon based on its "kinetic energy" - E=mc^2 is more of a mass/energy equivalence tool - as in, "if i turn this 5 kg of plutonium into energy, what will i get back?"

[Zaerosz]

Well, shit. And I used up my daily allowance of braining on that, too.

[RedWarrior0]

I believe a photon is one quantum mass unit, so any less mass and physics just plain goes wonky.

[kaijyuu]

Photons have a rest mass of 0. They're literally pure energy; a ripple in space/time.

They do have mass when moving (and they're always moving) which can be determined by good ol' e = mc^2.

[RedWarrior0]

Photons have a rest mass of 0. They're literally pure energy; a ripple in space/time.

They do have mass when moving (and they're always moving) which can be determined by good ol' e = mc^2.

Right. A moving photon has one quantum unit of energy and mass, and velocity of c.

Also, another tidbit: Mass is never created or destroyed. Mass does not convert into energy, matter does.

[Osmosis Jones]

Photons have a rest mass of 0. They're literally pure energy; a ripple in space/time.

They do have mass when moving (and they're always moving) which can be determined by good ol' e = mc^2.

Right. A moving photon has one quantum unit of energy and mass, and velocity of c.

Also, another tidbit: Mass is never created or destroyed. Mass does not convert into energy, matter does.

Errrr... reference please? My physics lecturers and textbooks taught me otherwise. Since my textbooks are still in packing crates, I'll undertake the cardinal sin and quote wikipedia;

The photon is currently understood to be strictly massless

Possibly you are thinking of momentum? Photons have an energy and a momentum, but not a mass. Their energy may be equivalent to the rest energy of a particle with mass m such that E = mc² holds, but they do not have a mass per se. Further, mass can be converted into energy;

Nuclear decay is a perfect example; when a nucleus decays into daughter particles, you can add the weights (in atomic mass units, natch). If the decay is purely particulate, the mass before and after will equal. If a gamma ray was also evolved, the masses are not, and the photon would have an energy equal to the rest energy of a particle with a mass equal to the discrepancy.

[kaijyuu]

Photons are "massless" in the sense that they aren't composed of matter. Note that photons are affected by gravity, which is only possible if they have mass. Maybe I'm using the term "mass" incorrectly; I dunno. I just know they're heavier the stronger they are.


I would be extremely hesitant to call them a quantum unit of energy, though, since different photons have different energy. A gamma ray has a lot more energy than an x-ray, and it's not on a quantum scale afaik (you can get photons of almost any wavelength; it's limited by the atom that's emitting the photon).

[Il Palazzo]

However, the scientific method relies on the formulation of hypotheses that are at least halfway coherent and to do that...

No, it does not. If it did, we wouldn't be where we are today.
A hypothesis needs to
1) Describe a mechanism in which observed phenomena function.
2) Be testable.

Those are the only real requirements for a hypothesis to be subjected to the Scientific Method. Coherency or distance from fringe are not required. In fact, most of the more revolutionary ideas are entirely on the Fringe and do throw out EVERYTHING. You know, like the fact the sun doesn't revolve around the earth after all? We take it for granted, but at one time that was throwing everything everyone knew and based information on out the window.

You're missing the point. When something new is discovered, some piece of information disagreeing with a given theory, it is not automatically branded "wrong", rejected, and forgotten in its entirety. After all it IS a theory - it explains some observed phenomena and can produce valid predictions. Unless you can refine the current theory, or find a completely new one that would explain the new bit of information as well as everything the previous theory did, then the conflicting information is going to be treated as an exception to the current theory.

Take for example light - up until late 19th century, the theory of wave-like properties of light was used to explain all of the observed phenomena. Then as more detailed information came through, and light was shown to sometimes behave as a bunch of particles, the previous theory(light is a wave) HAD NOT been rejected. It still described e.g.interference or diffraction.

Also, even when you do make an effort to refine the incomplete theory to take account for the problematic observation, you do not reject all of the postulates of the previous one. It's as if the last century's disovery of quantum and relativistic effects would have been enough to call the entirety of Newtonian laws of motion and gravity false.

Finally, this being a minor nitpick, the change from geocentricsm to heliocentrism was only revolutionary in the sense that it contradicted religious dogma, not in a sense of it being an original scientific idea. It simply changed the frame of reference, to one in which calculations of the motion of celestial bodies is easier. Also, the geocentric approach is still a valid one, and produces testable predictions.

People who scream "down with the wrong theory" seem to think that there can be no incomplete theories in science. They appear to have taken the realisation that science by definition can be wrong to the extreme, ready to tear down and cast into oblivion any theory that is shown to be lacking.

Note that photons are affected by gravity, which is only possible if they have mass.

That is a bold statement. Actually, Einstein's GR theory proposes a different explanation for gravitational lensing - the space-time is distorted around mass.