Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Osmosis Jones]

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.

So you're saying time has mass as well?

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

Ninjas everywhere :/

[kaijyuu]

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.

Isn't "space time distortion" the underlying cause of gravity anyway? Sort of like the opposite of buoyancy.


Anywho I don't claim to be an expert; most my knowledge is from wikipedia and a physics 101 course. So if I'm spouting BS, call me out on it

[RedWarrior0]

Ignore what I was saying in my last couple posts about the mass of a photon. That was me being stupid and misremembering.

[Kogan Loloklam]

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.

No, I am not missing the point here. The point here is that a major part of science is proving itself wrong and adjusting and adapting.
Yes there are a lot of fine nuances here. Like how in "the time of the change from geocentricsm to heliocentrism" religion wasn't just something someone had, but defined the very being of people of the time. Yes this was known previous to it's eventual adoption, but that wasn't the point. The point is that Science has an obligation to itself to question everything. To do anything else takes it out of the realm of science and into the realm of religion. Science isn't about beliefs, it's about facts. If those facts are comfortable, fine. If not, also fine. As long as it's questioned then science is still plodding in a forwardish direction.

I like your examples though. They highlight what I was trying to say. Everyone knew that light functioned like a wave, but suddenly it didn't. People probably went "Why is everyone always trying to prove science wrong?" regarding that too, when the truth is that questioning if it really does work like that is what makes science science.

[Virex]

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.

No, I am not missing the point here. The point here is that a major part of science is proving itself wrong and adjusting and adapting.
Yes there are a lot of fine nuances here. Like how in "the time of the change from geocentricsm to heliocentrism" religion wasn't just something someone had, but defined the very being of people of the time. Yes this was known previous to it's eventual adoption, but that wasn't the point. The point is that Science has an obligation to itself to question everything. To do anything else takes it out of the realm of science and into the realm of religion. Science isn't about beliefs, it's about facts. If those facts are comfortable, fine. If not, also fine. As long as it's questioned then science is still plodding in a forwardish direction.

I like your examples though. They highlight what I was trying to say. Everyone knew that light functioned like a wave, but suddenly it didn't. People probably went "Why is everyone always trying to prove science wrong?" regarding that too, when the truth is that questioning if it really does work like that is what makes science science.

I don't think the problem, or at least my problem, was that questions are being asked. However, what got me to RAEG is that there seems to be an idea that scientists are unwilling to ask these questions themselves and therefor have to rely on the benevolence of the public to ask them. Whenever something happens, people, and especially journalists and self-proclaimed amateur scientists, are running each other over to be the first to claim that this is "The end of relativity" or other such meaningless claims (for some reason there are very few calling this "the end of causality", even though that is at this point just as possible), without considering that these claims normally take quite a bit more than an anomalous reading to be acceptable. You'd think people that are serious about science would practice a bit of nuance. But instead we get the assumption, as aired by Aqizzar, that since Science constantly fails to revolutionize itself as expected, then scientists must be religiously clinging on to outmoded models and forcing everything to fit that view, while the fact of the matter is that said view is held because it works.

[Starver]

I'm wondering if someone has ever done an experiment with the ability to check whether a large cohort of photons is seen (or not seen) to gravitationally affect other photons, which would be definite proof (one way or another, once the accuracy is high enough) of whether the photons traditionally massed-as opposed to merely space-time bent. It would be a small effect, I can't think of anything experiment that would actually accumulate enough "source" photons in an area to make any significant (by many orders of magnitude) effect upon a any stream of test photons (perhaps something nuclear, but good luck with the measurement part of the apparatus, even if you can handle the "noise" in the system (and from without[1]), and I'm already pretty much wedded to the no (actual) mass idea, but perhaps there's an observable effect achievable through the Diamond Light Source synchrotron, or a similar project...


[1] I always remember measuring the constant big-G in an early Uni practical lab and learning how to spot when someone had entered the corridor (or for a couple adjacent floors) at the end of the wing the lab was in, from the way the experiment reacted...   On the other hand, nobody's going to be walking around in the vicinity of the nuclear source, unless they're called Banner.

[Siquo]

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.

Isn't "space time distortion" the underlying cause of gravity anyway? Sort of like the opposite of buoyancy.

We Don't Really Know. YET. This is one of the reasons why we're looking for the existence of the predicted Higgs-boson.


Anyway, causality is overrated . If the cookiejar is empty and my daughter has crumbs all over her face, according to her there's nothing that could explain that.

[Starver]

Quantum tunnelling also applies to children.

"Did you cross the road?"
"No."
"Did you cross the road?"
"No."
"Look, we're standing here on the other side of the road from where you should have been.  Did you cross the road."
"No!"

[Siquo]

Quantum tunnelling also applies to children.

Of course, the cookies quantum tunneled into her mouth. How could I have missed that?!

[Virex]

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.

Isn't "space time distortion" the underlying cause of gravity anyway? Sort of like the opposite of buoyancy.

We Don't Really Know. YET. This is one of the reasons why we're looking for the existence of the predicted Higgs-boson.

That whole discussion is moot anyway since we don't know if photons, or for that matter light, really exists either. For that matter, we don't know if neutrinos really exist either, for all we know, the measurements were caused by fairies with flashlights.

[Siquo]

Well, yeah. You're now dealing with stuff which we can only imagine with metaphores such as "particle" and "wave". For all we know they're strange, charming, up or down, or just fairies with flashlights.

Nevertheless, we can make calculations and predict those metaphores, so it's still relevant and not moot at all.

[Il Palazzo]

I'm wondering if someone has ever done an experiment with the ability to check whether a large cohort of photons is seen (or not seen) to gravitationally affect other photons, which would be definite proof (one way or another, once the accuracy is high enough) of whether the photons traditionally massed-as opposed to merely space-time bent.

That there is always a question of accuracy makes it impossible to have a "definite proof". All we can do, is establish an upper limit of photon mass, which can be done in experiments like this: http://www.princeton.edu/~romalis/PHYS312/Coulomb%20Ref/TuCoulomb.pdf . Check pages 4 and 8 for lists of all the experiments ever used. You need to have a good grasp of higher maths as well as physics to be able to grok how it's done though.
Ultimately, you're always going to be limited by the uncertainty principle, so you'll never really know for sure, no matter the accuracy of your measurements.

http://www.scribd.com/doc/62099162/22/Dispersion-of-starlight  describes experiments(starting with De Broigle's in 1940) like the one you have specifically proposed.

edit:

I like your examples though. They highlight what I was trying to say. Everyone knew that light functioned like a wave, but suddenly it didn't. People probably went "Why is everyone always trying to prove science wrong?" regarding that too, when the truth is that questioning if it really does work like that is what makes science science.

You know we(me, you, Virex) are all on the same side of the barricade, right?
Nobody is advocating not questioning science. What is being advocated is moderation in how it's done. In the light-as-a-wave example, you could have three basic reactions:
1.Science is religion, ergo light cannot be made of particles.
2.Science is wrong, ergo light cannot be a wave anymore.
3.Science changes to fit the data, ergo we've got wave-particle duality to describe behaviour of light.

What is being said, is that 2 is just as radical an approach, and just as bad as 1.

[Starver]

Some bedtime reading there, in the .PDF and I'll drag out my physics notes for the bits I've largely forgotten about over the last decade or so!

The Scribd one's giving me some problems (Firefox refuses to display pages on the page-shaped spaces, IE has the old "script causing IE to run slowly") but I'll see if I can grab that too.  Perhaps I'm making my machine do too many other things at the same time to represent the actual inner workings of spacetime.

[Virex]

I like your examples though. They highlight what I was trying to say. Everyone knew that light functioned like a wave, but suddenly it didn't. People probably went "Why is everyone always trying to prove science wrong?" regarding that too, when the truth is that questioning if it really does work like that is what makes science science.

You know we(me, you, Virex) are all on the same side of the barricade, right?
Nobody is advocating not questioning science. What is being advocated is moderation in how it's done. In the light-as-a-wave example, you could have three basic reactions:
1.Science is religion, ergo light cannot be made of particles.
2.Science is wrong, ergo light cannot be a wave anymore.
3.Science changes to fit the data, ergo we've got wave-particle duality to describe behaviour of light.

What is being said, is that 2 is just as radical an approach, and just as bad as 1.

I was actually arguing that
4. Guys! These new measurements that were just published totally invalidate the theory that light waves are one of those mass-particle-thingies! Guys! Guys? Why aren't you listening? Just because I don't have a clue doesn't mean you aren't wrong! Guys?!

Is getting a bit out of hand at times, especially when you consider that most can't distinguish between someone who knows the current theories and someone who's knowledge doesn't go beyond "light is supposed to be a mass-wave-particle-energy fluctuating field-something that flies through the aether and curves space".

[Il Palazzo]

The Scribd one's giving me some problems (Firefox refuses to display pages on the page-shaped spaces)

http://support.scribd.com/entries/23552-i-only-see-blank-space-where-the-document-s-contents-should-appear