Actually, quite a few of the photons hitting your eyes right now are billions of years old. Some as old as the universe itself (give or take).

Well THIS one is obviously a CG interpretation, perhaps arranging real photographs in a 3D program and then moving a virtual camera through them...
But the spectacular Hubble still photographs are REAL in the sense that they are graphs of real photons coming off real stuff out there. Just filtered for different spectra and then composited back together, packing more information into a single image.
http://hubblesite.org/gallery/behind_the_pictures/meaning_of_color/index.php
I know what you mean though. There are no "natural light" cameras on the Hubble. That would be a waste of space.

A spark is electrons moving rapidly from one place to another. But we see the spark. We can't see electrons. We can only see photons. So what's going on? Is a spark electrons or photons, or both?

So I'm guessing the rainbow 'wave' is the wave portion, and the squiggles under it are the photon? Or are the bumps on the 'wave' the photons? Anyone?

I was immediately apprehensive when the video stated that the light was confined to travelling along the nanowire and that it is reflected at either end and forms a standing wave. What is the photon interacting with at either end of the wire that reflects it?

The answer is that they haven't imaged light, but instead surface plasmons - oscillations of free electrons on the surface of the wire. Light is used to stimulate the plasmon, and the plasmon is used as a representation of light, which is imaged. However, electrons have mass and light does not.

A lot of reasonable people are calling this pop-science bullshit generated by the publicity department of whatever group published the study. Or rather, not that it's bullshit but that the explanation and headline are gross misrepresentations of what physical interactions are making the image.

photons are massless, its invariant mass..you will have to google that,,,,.neutrinos DO NOT travel faster than light.

The universe is the totality of existance and contains all there is..

The universe has no edge ....that would violate every accepted model of the universe...the universe is homogeneous and isotropic..

parts of the universe beyond our vision are not older than our part..we are the same age...

There is ZERO evidence to support any claim of any other universes..NONE..

You can hypothesis we live in a giants ass if you want,,,but there is no evidence to support that...the claim there are other universes,and the claim we exist in a giants ass, have the same amount of evidence..

AFAIK, photons have mass, but in a theoretical state of zero velocity they theoretically don't have mass (which can't currently be tested).

As for neutrinos, I said, "at or faster than the speed of light", not "faster than the speed of light". I never claimed they do go faster than the speed of light, because the jury's still out on that one. This is still a debate that divides the physics community and the matter is far from settled.

How about -sometimes photons appear to have mass, sometimes they don't.

As for Neutrinos, apparently they also can't exceed the speed of light. The experiment that said they might was flawed.
http://www.gizmag.com/neutrinos-sub-light-speed/22876/

Photon's have mass, certainly, but neutrinos go faster than light? First I've ever heard of that, are you sure you don't mean tachyons?

Umm... photons have mass.

Why is he saying they don't have mass?

Neutrinos also travel at or faster than the speed of light and have mass.

That's pretty much my favourite physics fact right there. From the point of view of a photon, travel is instantaneous. From the sun, from the next nearest star, from the big bang... It seemed to the photon that it was emitted and absorbed instantaneously.

We also had a brilliant bunch of lectures by Don Kurtz who told us about a book called Mr Tompkins in wonderland, in which the narrative was written by a guy who was a bicyclist in a world where the speed of light, c = 10 metres per second or so. http://en.wikipedia.org/wiki/Mr_Tompkins

We then did a bunch of questions about what that man experienced, what colour traffic lights were, what length his bike and roads were, and what time it said on the clock tower. Just great, that's what makes me want to lecture one day.

Unless you're a total dweeb, you know the Star Trek universe would totally win. Transporter, photon torpedo: bye-bye Death Star!

Sometimes I have a hard time understanding even how she wishes to explain it (yeah, I get it--relative alignment and whatnot).

I however don't view "whatever is in the mirror" as some kind of alternate universe or merely a switch of directions in my head (as she states, that most of us have a psychological impression to do so): I definitely see me, and not a "reverse".

I know, as others mentioned she is explaining it more than likely for younger audiences, but I wonder if there are better ways to do it. I find it far easier to understand it through the traditional physics explanation of photons bouncing off of objects, hitting the mirror and coming to my eyes (but, that isn't what she wants here; that is why I boiled it down into two words: relative alignment). It just makes sense, what could then end up happening--at least to me.

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