A few questions about light and how things work

In summary, the conversation discusses the concepts of light traveling on photons, redshift, and the behavior of photons when they collide. The possibility of light being overcome by gravity is also mentioned, with a reference to black holes. However, the conversation concludes with the suggestion that more research and reading is needed to fully understand these concepts.
  • #1
Ananki
Hello first time posting anything like this to people that have a better grasp on these ideas. Please pardon the lack of proper language structure.

So to my understanding that light travels on photons. The light from a source comes out in waves and particles. As it travels redshift will happen and in time will stop when it loses all energy if it never collided with anything because it was traveling on the edge of the expanding universe.

So when it stops is that it just done? I read that photons have the be absorbed by an electron. If no electron is there, and it no longer is moving in any direction for that instance it has no mass what would happen.

On that same thought when you collide two gamma wave photons they break down into the electron positron pairs then recombine and move on? Would this be because the two photons have higher mass then visible light and when they collide that tips in the just enough so they interact with each other and for an instant the no longer would be moving and thus mass would drop to 0 without being absorbed by an electron they create the pairs?

So would our loan photon turn into an electron and positron? Now if that is possible and accurate the pair would then merge? Fuse? Back into a photon like the gamma rays do? But then it again would have no mass. Or would it gain some from the redshift or the reaction of the electron and positron coming together? Thus it moving again in its original path. Could this be why the universe is expanding?

And I will stop right there. If you read the block thank you for your time and any insight to help me straiten my path out would be super thank you.
 
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  • #2
Ananki said:
So to my understanding that light travels on photons.
I don't think that is a good description.
Light can be described using the concept of photons.
Ananki said:
The light from a source comes out in waves and particles.
No it does not.
Ananki said:
As it travels redshift will happen
If it travels through space for billions of years: yes.
Ananki said:
and in time will stop when it loses all energy
It doesn't. The energy as function of time follows (roughly) an exponential distribution: it never reaches zero.
Ananki said:
because it was traveling on the edge of the expanding universe.
There is no such thing.

Unrelated to the cosmology questions:
Ananki said:
I read that photons have the be absorbed by an electron.
Every charged particle can absorb a photon.
Ananki said:
On that same thought when you collide two gamma wave photons they break down into the electron positron pairs then recombine and move on?
Most likely the photons just move on without an interaction. Very rarely, and only if their energy is sufficient, they produce an electron/positron pair (or heavier pairs, if the energy is sufficient) and these two particles then fly away. Even less frequent is a scattering: two outgoing photons, but going in different directions. If the energy is just right you can also produce a Higgs boson.
Ananki said:
Would this be because the two photons have higher mass then visible light and when they collide that tips in the just enough so they interact with each other and for an instant the no longer would be moving and thus mass would drop to 0 without being absorbed by an electron they create the pairs?
Photons have a mass of zero. I don't understand the rest of the question.
Ananki said:
So would our loan photon turn into an electron and positron?
No.
Ananki said:
Could this be why the universe is expanding?
That question doesn't make sense.
 
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  • #3
Ok I will look further into this and see if I can formulate a better question. Thank you.
 
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  • #4
Ananki said:
Ok I will look further into this and see if I can formulate a better question. Thank you.
You really need to read much more about this before you will be able to ask the 'right' questions. There are many good 'Popular Science" books which will improve your background knowledge. Stephen Hawkin's book A Brief History of Time has, apparently, been translated into 35! or more different languages so you should find a version that is easiest for you to read. The first chapter is more gentle than the rest but many total non Scientists (even) get a lot from it.
PS I did not imply Factorial 35 when I added the !. :biggrin:
 
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  • #5
So I have been looking around for an answer to a question I had and can't seem to find anything.

Can gravity overcome light.

What I mean by this. Could you introduce light to an amount of gravity that would overcome lights potential energy (don't know if I used that right) to return it to equilibrium.
 
  • #6
Ananki said:
Can gravity overcome light.

What I mean by this. Could you introduce light to an amount of gravity that would overcome lights potential energy (don't know if I used that right) to return it to equilibrium
https://en.wikipedia.org/wiki/Black_hole
 
  • #7
Aww yes a black hole. So what I understand is that they don't trap light, light "moves around" it. Because the closer it travels to the mass the longer it would take it to get to the other side and that's why we see the lensing.
Don't think that answered If gravity can stop it and reduce it to its resting mass. Or if light can/will at some point ignore it to continue its path
 
  • #8
Ananki said:
Aww yes a black hole. So what I understand is that they don't trap light, light "moves around" it. Because the closer it travels to the mass the longer it would take it to get to the other side and that's why we see the lensing.
Don't think that answered If gravity can stop it and reduce it to its resting mass. Or if light can/will at some point ignore it to continue its path
You didn't read the article yet, did you...? :smile:
 
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  • #9
I did read it, understand all of it maybe not. Is it saying that gravity can become a force that will effect everything even the models we currently have to explain what would happen? That as gravity increases (for lack of a better way of saying) the rules of the game change with it?

Secondary question if we created something that could enact that much gravity force on light we just black holed ourselves right?
 
  • #10
Ananki said:
Can gravity overcome light.

What I mean by this. Could you introduce light to an amount of gravity that would overcome lights potential energy (don't know if I used that right) to return it to equilibrium.

Your question, unfortunately, doesn't make any sense. Light has no equilibrium to return to.

Ananki said:
I did read it, understand all of it maybe not. Is it saying that gravity can become a force that will effect everything even the models we currently have to explain what would happen?

No, it's saying a lot of things, one of which may be that our models break down near the singularity of a black hole, but not that gravity becomes a force that affects our models.

Ananki said:
Secondary question if we created something that could enact that much gravity force on light we just black holed ourselves right?

Pretty much.
 
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  • #11
x712o.jpg
Ok cool. All this started with the CERN article about how the universe should not exist. And if that is possible or if the energy that the annihilation of the particles and anti-particles created could then reform into particles. If it could under what conditions would the energy released have to undergo this transformation.

One of those conditions that I was looking into was where the light that was released came to a stop and splits into pairs. As shown in the pic where the gamma ray collided with an electron.
 

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  • #12
Ananki said:
All this started with the CERN article about how the universe should not exist.

I don't think anyone at CERN is qualified to say whether the universe "should" or "shouldn't" exist, so I wouldn't pay too close attention to whatever the article claims.

Ananki said:
One of those conditions that I was looking into was where the light that was released came to a stop and splits into pairs. As shown in the pic where the gamma ray collided with an electron.

Note that the light never stopped moving. It scattered off of an atom, giving up part of its energy to a newly created electron-positron pair and an electron from the atom whose tracks you see, and then interacted with another atom to give up the rest of its energy to another electron-positron pair. It likely ceased to exist once this 2nd pair of particles was created.
 
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  • #13
Drakkith said:
Note that the light never stopped moving. It scattered off of an atom, giving up part of its energy to a newly created electron-positron pair and an electron from the atom whose tracks you see, and then interacted with another atom to give up the rest of its energy to another electron-positron pair. It likely ceased to exist once this 2nd pair of particles was created.
The second pair is probably from an independent photon.
 
  • #14
mfb said:
The second pair is probably from an independent photon.

Ah, good to know. Thanks!
 

FAQ: A few questions about light and how things work

1. What is light?

Light is a form of electromagnetic radiation that is visible to the human eye. It is a type of energy that travels in waves and can be seen as colors ranging from red to violet.

2. How does light work?

Light travels in waves and can be created through a variety of sources such as the sun, fire, or artificial light bulbs. When light hits an object, some of it is absorbed while the rest is reflected. The reflected light then enters our eyes, which sends signals to our brain to interpret the light as color and shape.

3. What is the speed of light?

The speed of light is approximately 299,792,458 meters per second, or about 670,616,629 miles per hour. This is the fastest speed possible and is used as a constant in many scientific calculations.

4. How does light interact with matter?

Light can interact with matter in three main ways: reflection, refraction, and absorption. Reflection occurs when light hits a surface and bounces off, changing its direction. Refraction is when light passes through a medium, such as water or glass, and bends due to a change in speed. Absorption is when light is absorbed by an object, causing it to heat up.

5. What is the electromagnetic spectrum?

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation, including light. It includes all types of electromagnetic waves, from radio waves to gamma rays. Light falls within a small portion of this spectrum, with shorter wavelengths being more energetic and longer wavelengths being less energetic.

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