The Bible tells us that the next step after creating the heaven and the un-formed earth, God said, "Let there be light" and there was light. (Genesis 1:3) [My speculation: That is when God fired up the sun.]
But for all of recorded history, we human beings have wanted to know more about light than that.
We have known that the lights that appear in the sky are way, W - A - Y far away, and that the light has to travel to get here.
Maybe that's all that was known until modern times when some enterprising scientists whose names I have forgotten made a rather successful attempt to discover the order of magnitude of the speed of light.
Now that we know to several decimal places "HOW FAST?" we come to the question "HOW?".
I speculated that it was somewhat like a rope-wave. The energy is transmitted along the physical rope and one can see the waves. (Only there is no rope. There is no medium. There is no "Aether".)
The roof fell in on me. Not because I suggested the rope-wave analogy. But because I speculated it in somebody else's Thread -- "hijacking". MigL suggested I ask the questions on my own Thread.
[An ancient folk-tale from India depicts a magician doing astounding tricks -- and for a grand finale, he causes a rope to stand vertically. He climbs the rope until he is clear up out of sight, and then pulls the rope up after himself. A cynic is depicted as saying, "Very good. Now do it without the rope."]
The rope analogy is not really much good for the transmission of light -- because light does it without the rope.
For those who have not done it, tie one end of a rope to a post, and pull the other end so that the whole rope is clear of the ground. Now move your hand. You can see a wave move along the rope. The energy of your hand is transmitted the whole length of the rope. At each point, the movement of each short length of the rope is transmitted to the next short length. If you move your hand up and down, you produce vertical waves. If you move your hand in a circle, you make circular waves.
Light is like that -- only faster -- and without the rope. Hmmmmm?
Fifty or sixty years ago our Physics Professor took apart the "Aether" explanation with an account of a careful experiment that involved the speed of star light six months apart. This not only had the observation points on the earth 2 AU apart, but going in the opposite direction. The light from that same star arrived at the same velocity. Some of us opined that some of the Aether was scooting right around with the earth. He very carefully demolished that speculation, too.
So (for me) it remains a mystery.
Is light little particles called Photons -- that travel at c?
Is light some kind of waves called Photons -- that travel at c?
Is light something ELSE -- called Photons -- that travel at c?
If light has no mass, how can it make the black and white vanes in those trick light-bulb (radiometer?) thingies revolve?
If light has no mass how does it force electrons to move when it hits a solar panel?
Edited by email@example.com, 19 May 2017 - 04:39 PM.