- #1
Sidewalk
- 10
- 0
Hi all -
This is the first time I have posted here, and at this point I have a very limited understanding of physics, and science in general, but I have found much of what I've read here (the parts which I could follow) to be very interesting.
I have a very simple question, but it's something I don't really understand, so I'd appreciate some feedback if anyone can spare a moment...
I understand that there are physical laws which state that matter as well as energy can be neither created nor destroyed, but that they simply change form.
I know light has unusal properties, something about being both a wave and a particle, and that nothing can travel faster than it as it is a physical impossibility. So if I were driving a car at close to the speed of light, the headlights in the front would still be lighting the way as the light emitted from them would be ahead of me - right?
My general question is what happens to light as it dissipates, or "fades"?
That is, picture someone standing in a dark wooded area with no light source other than a lantern hanging on a tree branch. The light is moving away from the lantern at the speed of light, thereby lighting the surrounding area, but as you move away from it, the world gets darker and darker (ie, the light fades).
I know we can see stars as they were years ago from billions of miles away and I assume this is because of their incredible luminosity, the light has enough energy to get here, but about 500 feet (let's say) away from the lantern the light has completely vanished.
OK - So here's my actual question:
I believe that light has no mass, correct me if I'm wrong, so I assume it's pure energy, and nothing but. What is light "made of" which gives it the properties of being visible, and if it loses these properties (or energy) after a certain distance (or time?) like the lantern light, where does that energy go and what is replacing it ?
Thanks for your patience, I'm so new at this type of discussion.
Cheers,
Sidewalk
This is the first time I have posted here, and at this point I have a very limited understanding of physics, and science in general, but I have found much of what I've read here (the parts which I could follow) to be very interesting.
I have a very simple question, but it's something I don't really understand, so I'd appreciate some feedback if anyone can spare a moment...
I understand that there are physical laws which state that matter as well as energy can be neither created nor destroyed, but that they simply change form.
I know light has unusal properties, something about being both a wave and a particle, and that nothing can travel faster than it as it is a physical impossibility. So if I were driving a car at close to the speed of light, the headlights in the front would still be lighting the way as the light emitted from them would be ahead of me - right?
My general question is what happens to light as it dissipates, or "fades"?
That is, picture someone standing in a dark wooded area with no light source other than a lantern hanging on a tree branch. The light is moving away from the lantern at the speed of light, thereby lighting the surrounding area, but as you move away from it, the world gets darker and darker (ie, the light fades).
I know we can see stars as they were years ago from billions of miles away and I assume this is because of their incredible luminosity, the light has enough energy to get here, but about 500 feet (let's say) away from the lantern the light has completely vanished.
OK - So here's my actual question:
I believe that light has no mass, correct me if I'm wrong, so I assume it's pure energy, and nothing but. What is light "made of" which gives it the properties of being visible, and if it loses these properties (or energy) after a certain distance (or time?) like the lantern light, where does that energy go and what is replacing it ?
Thanks for your patience, I'm so new at this type of discussion.
Cheers,
Sidewalk