I'm sure you don't believe that light will travel forever, you aren't taking into affect the laws of conservation, which very much effects photons as much as anything else. We don't know how long any light has been traveling, that's the funny thing about our perspective is that we don't have anything more than speculation about such things. But, if sufficient power is behind a photon, such as an explosion, I'm sure it can do some travelingLight will travel forever unless it hits something
Light from the deepest part of the Universe has been traveling for about 13 billion years before it hit earth
Not much of it but a tenny weeny bit
Most of it hits a lot of other stuff between the far distant reaches and tiny Earth
You do not see the light going sidewise passed Earth
and crisscrossing across space
because light is invisible
Why flat earth?
- Thread starter Tralay
- Start date
Your sureness is quaint in its simplicity but quite erroneous
I am sure
god does not exist
Earth has not been visited by super duper aliens
Earth is more than 6 to 10 thousand years old
I do not believe in souls ghost flying saucer UFOs << that's probably covered under aliens
I'm sure you can follow my train of thought
If not I will explain more the next time it leaves the station
DaveC426913
Valued Senior Member
Getting back to the OP:
I think this hits closer to the mark.
IMO, Flat Earthers aren't so much about literally the Earth is flat, than they are about 'don't blindly accept popular truths'.
The Flat Earth reference is simply a lightning rod for their message. It is more tongue-in-cheek - but delivered deadpan.
I think this hits closer to the mark.
IMO, Flat Earthers aren't so much about literally the Earth is flat, than they are about 'don't blindly accept popular truths'.
The Flat Earth reference is simply a lightning rod for their message. It is more tongue-in-cheek - but delivered deadpan.
Go on youtube and watch their videos, they are very literal about the earth being flat. I have a 10' long conversation in my facebook
messenger with a friend of mine who is trying his best to sway me towards the earth being actually flat with huge ice mountains surrounding it keeping the water from spilling over the edge, and he's dead serious.
They won't actually answer, but I did get my friend to say that he thinks that it is just eternal ground.
''eternal ground'' But I only weigh 9.5 stone (that's 133lbs)? But wouldn't I also be flat if that's true?
There is so much that is wrong with their theories that it actually bends the brain and causes symptoms akin to hemorrhaging lol.
exchemist
Valued Senior Member
There are some strange remarks here. Photons do not rely on "power" "behind" them to make them travel. They travel at c, indefinitely, until they encounter matter with which they can interact. As for the time of travel of photons in the cosmos, we certainly do have some indications of how long they have been travelling, since the red shift gives us a pointer to this.
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Well, no; we put light bulbs in different places because walls block light. At the scales you are talking about (inside structures) you will always be able to see a light if you are looking at it. The light doesn't "stop" after X meters or anything.
But move that 20 watt light ten miles away and you might need a small telescope to see it. Put it on the Moon and even that telescope wouldn't be enough. That's not because the light is stopping - it's because so few photons from the light are hitting your eye (or the telescope) that your eye can't detect it any more,
And, are they also suppose to be self sustaining electromagnetic waves? So, in theory they can be eternally travelling.
exchemist
Valued Senior Member
That is exactly what I am saying, yes. An individual photon does not dissipate. Though interestingly according to the hypothesis of cosmic inflation, the red shift is due to the expansion of space itself stretching out the wavelength and thereby reducing the frequency. So maybe I am wrong to say - at any rate on cosmic timescales - that an interaction with matter is required.
you can have a large room with no walls and it requires multiple light bulbs to sufficiently light the room, even though there are no walls in it.
You can view a table from 10 miles away with a telescope as well, so your statement doesn't prove that photons continue traveling. The photons are
only lighting up to a certain distance away from the source in direct proportion to the wattage pushing it.
"All isotropic localized sources of light create effectively spherical wavefronts for the light that spread out in all directions. Since the area of the spherical wavefront is increasing with distance as r2 and since the total energy in the light wave must be conserved, the energy density of the light dissipates according to 1/r2 . It's not that the light is destroyed or absorbed when traveling through free space, but that the light is stretched over a larger and larger area, and therefore must be locally weaker.
Even a laser beam, which seems to be perfectly collimated and go on for ever, experiences divergence because of diffraction. If you look over a large enough distance of propagation, you can see the laser beam light spreads out as it travels and gets dimmer at each point."
It's turtles all the way down.
exchemist
Valued Senior Member
Electromagnetic.
And we sort of "know" they exist, in a same way we "know" molecules exist, i.e. just as much as most things that are part of well-established theories in science. Do we "know" that electric currents exist in a circuit?
Well, we know what we call "current" exists in a circuit but what it actually is is still just a theory. Photons are just a theory as well and we don't know if there are actual photons "traveling" through the air or is the air full of photons already and they are just being excited in some way causing a chain reaction? Who knows? So I guess until we know for absolutely sure about the perpetual qualities of a photon, or any actual qualities of one, it's safer just to realize that we don't know.
Right. But you can always see the light - unless a wall blocks it.
You are seeing reflected photons from the table. Same same.
Nope, they go forever unless the are absorbed by something. You just lose the ability to detect them below a certain distance due to reduction of photons per square meter. They do not "expire."
Correct. But again, what happens is the total flux per square meter declines, and eventually your eye is no longer sensitive enough to see it.
that's all speculation anywhos