Re: Yeah, my impression is that he is unusual, but makes a lot of sense.

So what’s up with light acting like matter?

Understanding light really requires thinking in a non-intuitive way, which as you know is very difficult when we are barraged day-after-day with intuitive thought. Here's a pretty good explanation to some of them, better than I could answer. My stuff in brackets.

"If light has no mass, then why do black holes affect it? [ie, why does it bend?]

"Surprisingly enough, we see [that bending] happen to light, which has no mass. When light passes by black holes, as it shifts in the straight line of space-time, it doesn’t speed up its acceleration, which things with mass would do, because light has a universally constant velocity.

Since a photon travels by the shortest distance between two points, light appears to bend when it passes through the warped spacetime around a massive object. [Though it really doesn't. Space-time is bending, not the light.]

What this means is that gravity doesn’t directly bend light; it’s just that the spacetime around a massive object (a black hole) is warped and light takes the shortest path, making it look like the black hole is affecting the motion of light."

That’s a tough answer to grasp for me, because one so often thinks of light as an object IN space. Like a glowing photon marble in a shoebox. And if one runs a particular version of the Two-Slit experiment, light behaves exactly like that. Which is why light is so utterly confounding.

In that case though, that perception of light is a fallacy though. It’s not an object (it has no mass) and it’s not IN space. Maybe a glowing spot in a blob of Jello is more accurate. It’s the Jello that is changing, not the glowing spot.

Or, sort of like standing in front of one of those funky circus mirrors. You LOOK bent and distorted, even though you are not. Light acts as if it is bent, even though it is not. (See my other post below regarding ants walking on beach balls and banana shaped universes.)

Here's a shot at answering the E=MC2 question, and all of the gyrations it takes to make our description match what we observe. It’s akin to making sausage. My commentary in brackets.

“Light indeed carries energy and accomplishes this without having any mass. The Einstein equation that you are probably referring to is E = mc2.

[But this is a special case of Einstein’s equation when motion is zero, which most folks assume applies to ALL cases. So some of the confusion comes from using a specific equation as a general equation.]

The full equation is this:

E2 = (mc2)2 + (pc)2.

When a particle is at rest (p = 0), this general equation reduces down to the familiar E = mc2.

In contrast, for a particle with no mass (m = 0), the general equation reduces down to E = pc.

[Take this general equation, E2 = (mc2)2 + (pc)2, cancel out the mass=0 term, take the square root of both sides and you end up with E = pc.]

Since photons (particles of light) have no mass, they must obey E = pc and therefore get all of their energy from their momentum. [So we need to understand light in a way where energy comes only from momentum.]

If a particle has no mass (m = 0) and is at rest (p = 0), then the total energy is zero (E = 0). But an object with zero energy and zero mass is nothing at all.

Therefore, if an object with no mass is to physically exist, it can never be at rest. Such is the case with light. [Light clearly exists. So, we need a workaround.]

“…all objects with no mass can never be at rest [or they wouldn’t exist at all] and they must travel at speed c in all reference frames [by definition, to make the math work, and to exist, by our equations.]

Light is such an object, and the universal speed limit c is named the speed of light in its honor. But light is not the only massless object. Gluons and the hypothetical gravitons are also massless, and therefore travel at speed c in all frames. [And while we can’t explain this phenomenon considering light as a photon, we can if we consider light as a wave.]

Consider a long jump rope held taut at both ends by two girls. If one girl shakes her end of the rope violently enough to send a wave down the rope to the other girl, the wave can jerk the other girl. The rope has not transported any mass, but it still carries momentum through its waving motion. In this way, waves can have no mass but still carry momentum. This allows light to carry momentum, and therefore energy, without having mass.

[Which makes the equation E=pc describe what we see.]

[And why in an atomic bomb, the light is the courier of the energy from the uranium or plutonium, but not the actual energy itself.]

Fordtunate Son

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Re: Catch a wave and you're sittin' on top of the world.

Jul 8, 2024, 2:27 AM

CUintulsa®

>When matter becomes energy, we see a lot of light. Since light is not matter, or a form of matter, where is it coming from?

Here’s the short answer:

Light is the one of the products from the transformation of matter. So it does come from matter, as energy, but it is no longer matter itself, after its transformation. It’s new form is radiation, including some visible light.

Here's the longer answer:

Visible light is just one form of radioactive energy. And there's a lot more radiation out there that we can't see than we can. Here's a graph.

Stuff to the right of light is safe, stuff to the left is bad. Gamma rays are real bad. They go through lead, they stuff that protects you from X-Rays.

When atoms get picked on by some external force, three things can happen.

First, an atom can just get shaken up. That's not so bad, but it still produces radiation; thermal radiation. If you bend a wire fast enough, it will get hot. First, it emits radiation you can't see but you can feel, as heat. If you keep agitating and bending, it will eventually glow. That red hot is your bending moving the wire up the spectrum from infrared heat radiation that you can't see, to radiation that you can see, as visible light.

The second thing that can happen, if enough external force is applied to an atom, is that it can get its electrons split off. And that's sometimes bad. An atom without electrons is called an ion, and some are safe, while some are not.

Ionization can also result naturally, called radioactive decay. Like with uranium. And when uranium decays, it doesn't just give off heat, it gives off gamma rays and alpha and beta particles. All bad, and all radiation, carried from the clump of uranium to your cells by those mysterious wave and photon couriers, with bad results.

The third thing that can happen, if enough external force is applied to an atom, is not just the electrons getting stripped off, but the actual nucleus itself split apart. That's real bad. That can be a nuclear explosion. That's tinkering with the Strong Nuclear Force (SNF) that holds nuclei together. But as strong as it is it still has limits. A uranium atom is so big relative to the SNF that it's just barely hanging together. In other words, that sucker is ready to blow, atomically. And if you get enough of them together to mess with each other in a chain reaction, aka, critical mass, then Boom. Here’s a description:

“The core of the Hiroshima bomb contained about 140 pounds of uranium, but only about two pounds that underwent fission. [The rest failed to ‘ignite’, because after the 2 pounds exploded, critical mass dropped again.] “The amount of mass that was converted into pure energy was about half a dimes’ worth of mass. So, if you think about a dime, break it in two – that’s about how much matter disappeared and was converted into pure energy,” producing an explosive force equal to 15 thousand tons of TNT.”

That’s a lot of energy being generated from atoms being split, atoms being stripped, and atoms being jostled, all at the same time, in one hellaciously complex process. Here's what happens to all that radiation energy (some of which was now light) getting hauled around by massless, matterless waves and/or photons.

“As the nuclear explosion begins, the bomb and all of its components are heated to extremely high temperatures of around ten million kelvin. This causes these components to emit low-energy (“soft”) x-rays and high-energy (“hard”) ultraviolet waves. These x-rays and UV waves are absorbed by the air within a few metres of the device and this causes the air to be heated to temperatures of around one million kelvin, causing it to become incandescent and emit light. This is responsible for the initial, very fast (about three hundred millionths of a second after detonation) bright peak.

At the same time, the explosive shock wave itself (the hydrodynamic front) is expanding outwards and quickly compresses the air in front of it like a piston, causing it to become superheated. Inside this shock wave, the temperature is so high that the gas inside it become completely ionised [that is, all the atoms are stripped of their electrons, making still more radiation] and this makes the shock wave opaque. [The atoms absorb everything at that temperature, including the light they just created by becoming ionized in the first place.]

Light is still emitted in the front of the blast, because the shock wave itself is incandescent and is therefore emitting light outwards, ahead of itself, but this light is about one-tenth of the brightness of the preceding and following light. As the shock wave expands, it cools rapidly, and as it cools it becomes more transparent, allowing the light previously trapped behind it to escape. This is responsible for the second bright peak, which lasts much longer than the first because the full energy of the weapon is now being fully released, with nothing to block it. As the fireball expands it dissipates, and this is responsible for the gradual decrease in brightness.”

So the short version of that is the light does come from the matter, but then it’s no longer matter itself.

Here’s a really great article on nuclear explosions, that I scalped pieces of above. It doesn’t address light explicitly, but does talk about the SNF in relation to both fission and fusion.

https://www.ploughshares.org/issues-analysis/article/science-nuclear-explosions

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Yeah, my impression is that he is unusual, but makes a lot of sense.