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The speed of light

This crap is weird. Basically, mass and energy are the same thing. The speed of light is the constant that connects them. So if you want to know how much energy is bound up in a mass, you can calculate that with c. If you converted a given mass into pure energy (electromagnetic radiation) this tells you how much energy you'd have.

Honestly, this crap is mostly above my head. I read a book and think I get it but then a few years later I'm lost again.
Take the example of photosynthesis. Plants can't grow without sunlight, which must mean that light is a source of energy, otherwise it shouldn't be a factor. I suppose you could try to explain it away as the plant using the heat generated by the sun, but you can put a plant in a dark room thats heated and it won't grow. Weird stuff.
 
Take the example of photosynthesis. Plants can't grow without sunlight, which must mean that light is a source of energy, otherwise it shouldn't be a factor. I suppose you could try to explain it away as the plant using the heat generated by the sun, but you can put a plant in a dark room thats heated and it won't grow. Weird stuff.
That one’s not hard. The plant is biologically designed to absorb energy from light at certain frequencies in order to trigger the chemical reactions that break down CO2 into glucose. Looking closer, specific light frequencies excite electrons in the chlorophyll to the point where they may be ejected. When this occurs inside of a reaction center, the electron from the chlorophyll molecule jumps to a carbon dioxide molecule (starting the glucose creation) and is then replaced with one from a water molecule, thus creating oxygen.

Energy conveyed by any frequency other than the attuned will not excite the chlorophyll electrons and therefore there will be no reaction.
 
That one’s not hard. The plant is biologically designed to absorb energy from light at certain frequencies in order to trigger the chemical reactions that break down CO2 into glucose. Looking closer, specific light frequencies excite electrons in the chlorophyll to the point where they may be ejected. When this occurs inside of a reaction center, the electron from the chlorophyll molecule jumps to a carbon dioxide molecule (starting the glucose creation) and is then replaced with one from a water molecule, thus creating oxygen.

Energy conveyed by any frequency other than the attuned will not excite the chlorophyll electrons and therefore there will be no reaction.
"Absorb energy from light".
 
"Absorb energy from light".
I explained after that how the energy carried by light at the frequency attuned by the chlorophyll molecule excites electrons. That’s the “absorption.” That energy can be passed from chlorophyll molecule to molecule until it is released in fluorescence or it can be used in the reaction that creates O2 and glucose. Are you looking for why electrons are excited by energy?
 
I explained after that how the energy carried by light at the frequency attuned by the chlorophyll molecule excites electrons. That’s the “absorption.” That energy can be passed from chlorophyll molecule to molecule until it is released in fluorescence or it can be used in the reaction that creates O2 and glucose. Are you looking for why electrons are excited by energy?
That's kind of the basis of this thread. If light contains energy, how can the theory of general relativity be accurate?
 
That's kind of the basis of this thread. If light contains energy, how can the theory of general relativity be accurate?
The energy of the photons comes from their momentum and not their mass. Since light particles are always in motion, they can have zero mass and fulfill the equation. Light behaving as a wave allows it to have momentum without mass thus carrying energy without mass E = pc.
 
The energy of the photons comes from their momentum and not their mass. Since light particles are always in motion, they can have zero mass and fulfill the equation. Light behaving as a wave allows it to have momentum without mass thus carrying energy without mass E = pc.
Ok, but that means that light is variable and not a constant. If photons do contain energy, that means they were blasted off from the source without being affected by its gravity. That sounds fine, but it also makes black holes impossible.
 
Ok, but that means that light is variable and not a constant. If photons do contain energy, that means they were blasted off from the source without being affected by its gravity. That sounds fine, but it also makes black holes impossible.

An interesting thing about the equation for "escape velocity" - it's independent of the mass of the object trying to escape. A massive object is going to require more energy than a smaller object, but the escape velocity required is the same for both. Earth's escape velocity is 11.2 km/s. You can use that to calculate how much energy you'd need to escape earth's gravity.

The equation is pretty simple. For a given mass, you can solve for the radius at which the speed of light is the escape velocity. That's where the event horizon of a black hole is.

Instead of thinking of gravity as a force pulling on the photons, think of it as curved space. When the space is so curved that every single photon path you can plot turns back on itself, you have a black hole. It's like launching baseballs from earth at 11.1 km/s - eventually earth will pull them back in. If you're an observer with a baseball detector far far away, no baseball will ever reach you.
 
The only thing I am sure of is what ever the speed of light is at any moment under any situation, is exactly that much faster than neurons firing in our new President's brain.
 
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