Posted on 05/19/2016 1:06:30 PM PDT by BenLurkin
Ever since Democritus... argued that all of existence was made up of tiny indivisible atoms, scientists have been speculating as to the true nature of light. Whereas scientists ventured back and forth between the notion that light was a particle or a wave until the modern, the 20th century led to breakthroughs that showed that it behaves as both.
These included the discovery of the electron, the development of quantum theory, and Einstein’s Theory of Relativity. However, there remains many fascinating and unanswered questions when it comes to light, many of which arise from its dual nature. For instance, how is it that light can be apparently without mass, but still behave as a particle? And how can it behave like a wave and pass through a vacuum, when all other waves require a medium to propagate?
...
By the late 19th century, James Clerk Maxwell proposed that light was an electromagnetic wave, and devised several equations (known as Maxwell’s equations) to describe how electric and magnetic fields are generated and altered by each other and by charges and currents. By conducting measurements of different types of radiation (magnetic fields, ultraviolet and infrared radiation), he was able to calculate the speed of light in a vacuum (represented as c).
In 1905, Albert Einstein published “On the Electrodynamics of Moving Bodies”, in which he advanced one of his most famous theories and overturned centuries of accepted notions and orthodoxies. In his paper, he postulated that the speed of light was the same in all inertial reference frames, regardless of the motion of the light source or the position of the observer.
(Excerpt) Read more at universetoday.com ...
There are a few like that. When I talk to students about energy, I always start out by saying that I am happy to talk about energy, just don’t ask me what it is. Because I don’t know. Nobody does, other than in terms of abstractions, “the ability to do work”, a potential field, a property of matter, the conserved quantity associated with the temporal invariance of the Lagrangian density. But what is it, really, in its essence (and no dodging by invoking Special Relativity)?
Of course not, nor does your horn work........
Reflection. Yes, I agree. Only I think of it as a shadow. It is like we are waiting for the next eureka moment, which will change everything.
Actually if you look at the night sky, even in the darkest places on Earth, the furthest STARS you can see aren’t much more than 1500 light years away.
The furthest galaxy you can see without a scope may be M81 and it has to be REAL dark and you better have good eyesight.
Occasionally there will be a supernova in some close galaxy that you can see with a scope, that would be the furthest star you can see with a scope. There was one in M82 a few years ago that could easily be seen with a small scope.
The furthest galaxy you can see with a telescope is 3c273.
If I remember right its 2.3 Billion LY. You need a good scope to see it.
Basically, yes.
A real car, consisting of a certain amount of mass, would require an infinite amount of energy to attain that speed.
Slightly more realistically, let's assume that the car is traveling at 99 percent of the speed of light. Then imagine that a person at a distance in front of the car of one light year detects the light coming from the headlights.
Although the light would probably be very dim, the observer would measure the photons as having a speed of 300 million meters per second. He would also detect a pronounced blue-shift in the frequency of the light. Each photon would carry a great deal of energy; much more than would be measured by an observer moving with the car.
Finally, after 3.65 days of observing this unusual light, the observer would be run over by an extremely fast moving car.
You're onto something there. As some would say, just because you can't see it, doesn't mean it isn't there. The so-called "vacuum" appears empty to us because we can't detect anything in it. There is a bunch of dark matter in the Universe hiding from us. It fills the so-called "vacuum" with energy fields and light propagates through that medium. It also binds celestial bodies together with electro-magnetic energy. Someday scientists will be able to readily detect dark matter and how it exists within the "vacuum" of space.
It's the pictures that got small.
If you are traveling the speed of light in your car and turn on the headlights, do they light up anything? ;-)
Of course not, nor does your horn work........
Sorry speed. I’d blame auto-correct, but it’s just an operator head-space error.
Whereas heavy travels slowly...Thus we have a unified theory...
Usually in a straight line.
“How does one travel light? Never figured that one out.”
One carryon, no checked baggage.
That was just a great time to be a scientist. You could do cutting edge research with everyday things like lanterns and copper wire and corks and apples and kites and stuff.
Nice explanation.
Traveling at light speed is probably not a good idea anyway. Bumping your car into a clump of dust at light speed would release a huge amount of energy, similar to a small nuke.
Thanks.
Whereas heavy travels slowly...Thus we have a unified theory...
One carryon, no checked baggage.
Wish I could learn to travel light. I am spoiled by the fact that most of my travel is by car.
Well, we know that it travels at least one mile per second slower than the speed of dark, because dark can't be see leaving the room when ya turn on the light. Thanks BenLurkin.
Good answer to the car question.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.