I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

Leave it to a man to come up with a "double slit" experiment. I remember Vanessa Williams in the Penthouse spread back in the 1980s. There is no "quadruple ball" experiment . Never heard that showing up in Playgirl.

^^^^^^ Translation..... "Beer".... "Coconut rum"..... Too much time on my hands.

In all seriousness. It still freaks me out to think that it is both particle and wave. Neutrinos also freak me out thinking about how small they are.

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

No, Einstein did NOT say that light is heavy. Even through the equation E=mc^2, it is not massive because the *correct* and most general equation is E^2 = m^2 c^4 +p^2 c^2 where p is the momentum. In the case of light, m=0 and E=pc.

Now, in general relativity *all* forms of energy contribute to the gravitational field, so mass is not directly required. Conversely, light *does* move along a different path than it could if it were massive (a null path--massive paricles do not travel along null paths).

Next, the classical ideas of matter have to be modified because of what we know about the atomic realm. The reason 'classical matter' takes up space is because of something known as the Pauli exclusion principle. It applies to any 'particle' with 'half-integer spin'. Such particles are also known as fermions. For example, electrons and protons are fermions.

But then, so are neutrinos, which pass through matter quite easily. To further complicate things, electrons are thought to be point particles: they technically do NOT take up space. But they do repel each other which forces them apart. This repulsion is partily due to the fact that they are fermions. This is why most ordinary matter 'takes up space'.

There are also particles called bosons that do NOT obey the Pauli exclusion principle. While fermions don't like to be together, bosons very much do. And guess what? Photons are bosons, not fermions. And yes, there are bosons which have mass. The Higg's boson actually has a mass about the same as an atom of Cesium.

The upshot? Classical ideas about mass and matter have to be modified considerably when faced with the realities of the atomic and subatomic realms. Things just don't work at that level based on classical mechanics.

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

It helps if you think of a photon as not so much a particle, but as a package of energy in the electromagnetic field as a whole (it's both, smart people tell me).  A packet of energy would necessarily have no mass, but energetic fields react to gravity.

I've probably worded this badly.

Boru

(July 7, 2019 at 4:54 pm)polymath257 Wrote:

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

No, Einstein did NOT say that light is heavy. Even through the equation E=mc^2, it is not massive because the *correct* and most general equation is E^2 = m^2 c^4 +p^2 c^2 where p is the momentum. In the case of light, m=0 and E=pc.

Now, in general relativity *all* forms of energy contribute to the gravitational field, so mass is not directly required. Conversely, light *does* move along a different path than it could if it were massive (a null path--massive paricles do not travel along null paths).

Next, the classical ideas of matter have to be modified because of what we know about the atomic realm. The reason 'classical matter' takes up space is because of something known as the Pauli exclusion principle. It applies to any 'particle' with 'half-integer spin'. Such particles are also known as fermions. For example, electrons and protons are fermions.

But then, so are neutrinos, which pass through matter quite easily. To further complicate things, electrons are thought to be point particles: they technically do NOT take up space. But they do repel each other which forces them apart. This repulsion is partily due to the fact that they are fermions. This is why most ordinary matter 'takes up space'.

There are also particles called bosons that do NOT obey the Pauli exclusion principle. While fermions don't like to be together, bosons very much do. And guess what? Photons are bosons, not fermions. And yes, there are bosons which have mass. The Higg's boson actually has a mass about the same as an atom of Cesium.

The upshot? Classical ideas about mass and matter have to be modified considerably when faced with the realities of the atomic and subatomic realms. Things just don't work at that level based on classical mechanics.

You couldn't leave the lesbian fantasy to a simpleton like me? You actually took the time to try to explain real science?

What is next, I actually have to learn to tie my shoes all by myself?

Sometimes there isn't enough Alex's. (Alexses?, Alexi?)

Don't think gravity and mass, think gravity and curved space.

Edit: No offense polymath, some of us just miss Alex.

(July 7, 2019 at 4:58 pm)BrianSoddingBoru4 Wrote:

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

It helps if you think of a photon as not so much a particle, but as a package of energy in the electromagnetic field as a whole (it's both, smart people tell me).  A packet of energy would necessarily have no mass, but energetic fields react to gravity.

I've probably worded this badly.

Boru

I've been cracking jokes  in this thread as everyone  can see. But in all seriousness, that blur between particle and wave really does freak me out.

It is hard for laypeople to view particle and wave as fluid and not either/or.

It may be crude to think of it this way, but the melting villain from Terminator 2 might be a crude analogy.

But between particle and wave, that is the ultimate "Ford vs Chevy", "Cowboys vs Redskins" when the reality is "neither for or against" but both.

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

Light is propagation of energy in a medium whether seen or unseen. Whether aether or glass. An electromagnetic waveform, with rarefactions and compressions, up down left right, not a particle. With a rate of induction not a speed. The medium exists but light does not. The unseen medium is usually called "Dark Energy" or aether and it's everywhere. E = MC2 is stupid!

(July 7, 2019 at 5:33 pm)Haipule Wrote:

(July 7, 2019 at 4:01 pm)Rhondazvous Wrote: I’ve been laboring under the impression that photons are massless. But I’m now reading Einstein’s Universe by Nigel Calder in which he claims that Einstein said light is heavy
In some ways, it does seem that light must have mass. How could gravity bend light or trap light in a black hole if it had no mass? At the same time light doesn’t have the second property of matter. It doesn’t take up space. It wouldn’t be able to pass through solid objects such as glass, plastic. Or ice if it took up space. Only in intense concentration (laser) does light appear to take up space and  move material objects out of its way.

So, are we making a difference between mass and matter? Between photons and light?

Light is propagation of energy in a medium whether seen or unseen. Whether aether or glass. An electromagnetic waveform, with rarefactions and compressions, up down left right, not a particle. With a rate of induction not a speed. The medium exists but light does not. The unseen medium is usually called "Dark Energy" or aether and it's everywhere. E = MC2 is stupid!

We’ve been through this.   If you were born after 1880s you would have to be an uneducated ignoramus to sprout nonsense like this.    Are you an uneducated ignoramus or not?

If you are not, you should know not to say things like this.  If you are, you should know not to say anything.

(July 7, 2019 at 6:10 pm)Anomalocaris Wrote:

(July 7, 2019 at 5:33 pm)Haipule Wrote: Light is propagation of energy in a medium whether seen or unseen. Whether aether or glass. An electromagnetic waveform, with rarefactions and compressions, up down left right, not a particle. With a rate of induction not a speed. The medium exists but light does not. The unseen medium is usually called "Dark Energy" or aether and it's everywhere. E = MC2 is stupid!

We’ve been through this.   If you were born after 1880s you would have to be an uneducated ignoramus to sprout nonsense like this.    Are you an uneducated ignoramus or not?

If you are not, you should know not to say things like this.  If you are, you should know not to say anything.

Wait! That is not fair. I have a lesbian fantasy of two double slits. Now, they cant be pro slit and wave at the same time, can they?

If they are also pro particle at the same time, then they should promote billiards. Balls lives matter too.