about Bob's article on absolute or relative time

[Johnny]

Photons having zero mass is another whole can of worms in regards to modern physics.

They say photons have no mass but that they do have momentum, which is proven by the small but measurable recoil that lasers experience.

So if momentum = mass x velocity (p=mv), how then does something with no mass have momentum?

Photons have no rest mass, but they do have "relativistic mass". Their momentum is defined by Einstein's famous equation:

E² = m²c⁴ + p²c²

substituting m=0

E² = p²c²
or
E = pc

solving for momentum:
p = E/c

Experimentally, it's virtually impossible to show that photons actually have 0 rest mass because there is always some margin of error in our measurements. The best we can do is put an upper limit on what its mass could be. Right now that upper limit is 3.9 × 10^-22 times smaller than an electron.

I saw your response to my last post but I simply don't have the time to type up a substantive response. I just want to post a quick note to say that it's not that I'm ignoring you, I'm just got too many pots on the stove to be a consistent participant in the thread.

Thanks Clete.

 

[pozzolane]

Photons having zero mass is another whole can of worms in regards to modern physics.

They say photons have no mass but that they do have momentum, which is proven by the small but measurable recoil that lasers experience.

So if momentum = mass x velocity (p=mv), how then does something with no mass have momentum?

They also have energy. How does something without mass have energy?

 

[dan1el]

How, exactly, did this go against the idea that c was constant, or that nothing acted faster than light?

If we noticed the change in gravity before everything went black, that would mean gravity traveled faster than light.

 

[Lighthouse]

Wow. Are you gonna use the "my dad can beat up your dad" line next?

You put my level of comprehension into question. And I responded with the facts.

I only assumed that it was because that's exactly what I was conveying to you.

You apparently have no idea what you said.

RE: Photons having zero mass.



:chuckle:

OK, Lighthouse, you got me. Photons have mass. One photon is equal to 17 LHBM-eons ⁽¹⁾. Each LHBM-eon having the mass force of a single flap of a pink fairies wing, or 3 sprinkles of pixie dust.

1) LHBM-eon - Weigh scale derived on "Lighthouse's Brain Mass"

As Clete pointed out, they do have momentum. So, how is that possible?

And how are lasers that can cut through diamonds possible? And how does gravity effect light? I mean, if photons have no mass that is...

If we noticed the change in gravity before everything went black, that would mean gravity traveled faster than light.

Thank you. I don't know why that was so hard.

Of course, the idea that gravity travels is another problem. There is no need for it to travel. It has pull. That is all. It doesn't move from one source to another. It doesn't travel.

 

[Memento Mori]

And how does gravity effect light? I mean, if photons have no mass that is...

Gravity curves space time. And since light has to travel through space-time, it appears slower.

 

[Johnny]

As Clete pointed out, they do have momentum. So, how is that possible?

They have energy, and momentum can also be defined as "E/c".

And how are lasers that can cut through diamonds possible?

They have energy.

And how does gravity effect light?

Light travels through curved space, thus altering its apparent trajectory.

 

[Lighthouse]

Gravity curves space time. And since light has to travel through space-time, it appears slower.

So, space, which is nothing, and time, which is intangible, are affected by gravity...

Do I really need to explain how completely illogical that is?

And, the irony is that if some of you people could accept the Bible as being true in some cases, including the ones about the heavens being spread out like a curtain, we might have a bit of an agreement here.

They have energy, and momentum can also be defined as "E/c".

It makes more sense that we can't measure their mass, rather than stating that they have n mass as a fact. Especially after the argument that there are no facts in science.

They have energy.

Doesn't energy require mass? E=MC²

Light travels through curved space, thus altering its apparent trajectory.

So, are you saying light isn't affected by gravity?

 

[pozzolane]

You apparently have no idea what you said.

Right, because you know far better what I mean than I do. Not only are you incredibly stupid, but you are incredibly arrogant, too.

As Clete pointed out, they do have momentum. So, how is that possible?

Because they have energy.

And how are lasers that can cut through diamonds possible? And how does gravity effect light? I mean, if photons have no mass that is...

Space-time is curved by gravity. Light moves through the curved space-time.

Of course, the idea that gravity travels is another problem. There is no need for it to travel. It has pull. That is all. It doesn't move from one source to another. It doesn't travel.

Do you ever just sit and contemplate for a few minutes/hours about something before you open your mouth? There have been a few videos already posted that have nice animations that graphically show how mass curves the "fabric" of space-time resulting in what we feel as "gravity". If you watched them and even just half-attempted to understand, you wouldn't have said anything as remotely stupid as you just did. Gravity has a range at which its effect has influence on another body with mass. If that mass were to suddenly vaporize, how would it be possible for the effects of the gravitational change to be felt first if nothing can travel faster than the speed of light. Nothing is instantaneous. The universal speed limit is light in a vacuum. But Newtons theory predicts that the first thing noticed would be a sudden loss of gravitational "pull". This is impossible.

 

[Stripe]

Space-time is curved by gravity. Light moves through the curved space-time.

Or one could eliminate the middle-man and simply say that gravity affects light.

Why do we need to make a non-physical thing into something "real" in order to explain something?

 

[pozzolane]

Or one could eliminate the middle-man and simply say that gravity affects light.

Why do we need to make a non-physical thing into something "real" in order to explain something?

Right. So we drop the theory that makes extremely accurate predictions, and accurate explanations of how and why, for... what?...magic? Gravity affects light because...?! Magic?

Because the light fairies that carry the electromagnetic radiation through space prefer to have a rest at every rock, moon, and galaxy they fly through. Right Stripe?

 

[dan1el]

Thank you. I don't know why that was so hard.

I won't say anything about the difficulty, but it should've been unnecessary to point out if you, as you've claimed to do, have a basic understanding of relativity.

Of course, the idea that gravity travels is another problem. There is no need for it to travel. It has pull. That is all. It doesn't move from one source to another. It doesn't travel.

Why should the universe conform to what you think it needs and doesn't need to do?

While current observations do not yet provide a direct model-independent measurement of the speed of gravity, a test within the framework of general relativity can be made by observing the binary pulsar PSR 1913+16. The orbit of this binary system is gradually decaying, and this behavior is attributed to the loss of energy due to escaping gravitational radiation. But in any field theory, radiation is intimately related to the finite velocity of field propagation, and the orbital changes due to gravitational radiation can equivalently be viewed as damping caused by the finite propagation speed. (In the discussion above, this damping represents a failure of the "retardation" and "noncentral, velocity-dependent" effects to completely cancel.)

The rate of this damping can be computed, and one finds that it depends sensitively on the speed of gravity. The fact that gravitational damping is measured at all is a strong indication that the propagation speed of gravity is not infinite. If the calculational framework of general relativity is accepted, the damping can be used to calculate the speed, and the actual measurement confirms that the speed of gravity is equal to the speed of light to within 1%. (Measurements of at least one other binary pulsar system, PSR B1534+12, confirm this result, although so far with less precision.)

Source.

So, space, which is nothing, and time, which is intangible, are affected by gravity...

Do I really need to explain how completely illogical that is?

I think you need to get rid of some misconceptions.

It makes more sense that we can't measure their mass, rather than stating that they have n mass as a fact. Especially after the argument that there are no facts in science.

It doesn't make more sense when we have lots of evidence indicating it has no mass, and none indicating it does.

Doesn't energy require mass? E=MC²

That equation relates rest mass to energy, if I'm not mistaken.

 

[Stripe]

Right. So we drop the theory that makes extremely accurate predictions, and accurate explanations of how and why, for... what?...magic? Gravity affects light because...?! Magic?

Because the light fairies that carry the electromagnetic radiation through space prefer to have a rest at every rock, moon, and galaxy they fly through. Right Stripe?

Don't be a retard.

Theorising that gravity affects light will leave us just as capable of recording observations correctly and using that knowledge to make predictions.

In fact it should make things easier to comprehend.

You do not know how gravity affects space. It is no loss to admit I do not know how gravity affects light.

 

[dan1el]

Or one could eliminate the middle-man and simply say that gravity affects light.

Why do we need to make a non-physical thing into something "real" in order to explain something?

Well, there's the whole thing about all the evidence indicating that's what's actually happening. I have no doubt, however, that you, as usual, won't care about that. It's just not how you roll, I guess.

 

[Johnny]

Space-time is curved by gravity. Light moves through the curved space-time.

Or one could eliminate the middle-man and simply say that gravity affects light.

In general relativity, gravity does not curve spacetime (though its often stated this way in common vernacular). Gravity is curved spacetime. Gravity is not a force under general relativity.

Don't be a retard.

Theorising that gravity affects light will leave us just as capable of recording observations correctly and using that knowledge to make predictions.

In fact it should make things easier to comprehend.

You do not know how gravity affects space. It is no loss to admit I do not know how gravity affects light.

See above.

Once again we're back to stripe favoring the dropping of theories that explain a vast number of phenomena and that have been experimentally supported in favor of "guesswork".

Your position continues to be ludicrous, and your continual support of it is completely anti-science. And as such, your relevance in scientific discussions continues to shrink.

Why do we need to make a non-physical thing into something "real" in order to explain something?

Even though you don't know the answer to this question, do you suppose that scientists have a reason to accept this model?

 

[Stripe]

Even though you don't know the answer to this question, do you suppose that scientists have a reason to accept this model?

I know the answer to my question. Relativity is required because a constant is required by which sense can be made of data that is affected by the tools used to sample it. The answer to this problem is to apply a mathematical correction called relativity. This application of mathematics does not force a physical nature upon the universe.

 

[pozzolane]

In general relativity, gravity does not curve spacetime (though its often stated this way in common vernacular). Gravity is curved spacetime. Gravity is not a force under general relativity.

Yes, thank you Johnny! This is an important distinction.

 

[Memento Mori]

So, space, which is nothing, and time, which is intangible, are affected by gravity...

Do I really need to explain how completely illogical that is?

Yes actually, you do need to explain how this is illogical.

Space is measurable. Time is measurable. Get a ruler and a watch. Unless you exist as a singularity, in which case you should definitely contact some scientist.

 

[Lighthouse]

Right, because you know far better what I mean than I do. Not only are you incredibly stupid, but you are incredibly arrogant, too.

I didn't say anything about what you meant. Pay attention.

Because they have energy.

:bang:

E=MC²

Space-time is curved by gravity. Light moves through the curved space-time.

Prove that space and time are connected...

And then prove that time curves.

Do you ever just sit and contemplate for a few minutes/hours about something before you open your mouth? There have been a few videos already posted that have nice animations that graphically show how mass curves the "fabric" of space-time resulting in what we feel as "gravity". If you watched them and even just half-attempted to understand, you wouldn't have said anything as remotely stupid as you just did. Gravity has a range at which its effect has influence on another body with mass. If that mass were to suddenly vaporize, how would it be possible for the effects of the gravitational change to be felt first if nothing can travel faster than the speed of light. Nothing is instantaneous. The universal speed limit is light in a vacuum. But Newtons theory predicts that the first thing noticed would be a sudden loss of gravitational "pull". This is impossible.

Unless of course gravity doesn't travel. It only pulls. That's it.

And seeing as how it's eight seconds for the light to travel, I don't think we are going to notice the difference in gravity before the light disappears.

I won't say anything about the difficulty, but it should've been unnecessary to point out if you, as you've claimed to do, have a basic understanding of relativity.

Did I say that? When and where?

Why should the universe conform to what you think it needs and doesn't need to do?

:squint:

Source.

:doh:

I think you need to get rid of some misconceptions.

Such as?

It doesn't make more sense when we have lots of evidence indicating it has no mass, and none indicating it does.

It has no measurable mass, but it has potential energy. If it didn't then it couldn't have any kinetic energy, i.e. it would never be not at rest. But light is the opposite, never at rest...

That equation relates rest mass to energy, if I'm not mistaken.

Mass at rest to potential energy. But kinetic energy cannot exist if there is no potential energy. And potential energy cannot exist if there is no mass.:think:

Yes actually, you do need to explain how this is illogical.

See above.

Space is measurable. Time is measurable. Get a ruler and a watch. Unless you exist as a singularity, in which case you should definitely contact some scientist.

:rotfl:

Of course they are measurable. And?

 

[Memento Mori]

:rotfl:

Of course they are measurable. And?

Therefore, they exist. Unless you can make calculations and measure something which doesn't exist? I certainly don't know how to do it.

 

[Johnny]

Why do we need to make a non-physical thing into something "real" in order to explain something?

Even though you don't know the answer to this question, do you suppose that scientists have a reason to accept this model?

I know the answer to my question. Relativity is required because a constant is required by which sense can be made of data that is affected by the tools used to sample it. The answer to this problem is to apply a mathematical correction called relativity. This application of mathematics does not force a physical nature upon the universe.

That's not an answer to your question. You also didn't answer my question.

You also ignored the rest of my post.

More and more you appear as if you're taking blind stabs in the dark, disagreeing at every turn, and saying things like "cut out the middle man" -- which shows that you haven't even bothered to educate yourself on a basic wikipedia level about that which you're arguing against. Really, I can't count the number of basic misunderstandings you've been corrected on by the participants in this thread. It's not even that you have to think the theory is correct, you just don't even show the slightest understanding of the theory. Perhaps you're hoping that one of these blind stabs will stick, and then you'll be able to follow that line of argument.