[lutusp]

> Star mass bends space, and the light merely "appears" to bend, when it traverses that space. It doesn't actually bend.

On the contrary, it actually bends. Spacetime curvature is a real, not an apparent, effect.

"Spacetime tells matter how to move; matter tells spacetime how to curve." -- John Wheeler

More on this topic: https://en.wikipedia.org/wiki/Einstein_ring

[ClayFerguson]

The light is traveling in a straight line ALWAYS, but merely appears (to us) to bend, because the space it's traveling thru (in a straight line) is itself bent. The space itself is bent. The light goes straight.

That's the distinction i was attempting to point out, when I said if mankind had visually noticed star-induced 'lensing' (before Einstein explaining what to expect) we would have ASSUMED the light itself was bending, and that space was 'flat' (unbent). Thinking space is flat and light is bent (the opposite of what is true), would have been the same kind of blunder we are making today believing that Dark matter/energy is actually real.

[lutusp]

> The light is traveling in a straight line ALWAYS, but merely appears (to us) to bend, because the space it's traveling thru (in a straight line) is itself bent. The space itself is bent. The light goes straight.

Space is curved, and the light passing through it is also curved. That was the point of my link to the Einstein Ring page -- to show that light is in fact curved along with space.

The first important confirmation of GR was an experiment conducted in 1919 that showed curved light paths of starlight passing near the sun, observed during an eclipse.

If you happened to be located near a black hole, at 1.5 times the radius of the event horizon, by looking along a tangential path, you would see the back of your own head, regardless of which direction you looked. The reason? Light is curved along with space.

It's not accurate to say, as you are doing, that light always follows straight paths. It is accurate to say that light follows the curvature of the space through which it passes.

> ... would have been the same kind of blunder we are making today believing that Dark matter/energy is actually real.

Try to avoid moving ahead of the evidence. The present evidence is that dark matter and energy are real, again following Occam's razor. But I can't say these things are real as a matter of concluded fact, and you can't say they aren't. No one knows, and science requires us to wait for observation and theory to sort it out. Science doesn't progress by proclamation, but by way of theories that resist sincere efforts at falsification.

Apropos: https://youtu.be/b240PGCMwV0?t=37

[ClayFerguson]

I do understand why you think what you do. Most physics articles (and even the Wikipedia page on Gravitational Lensing) are explaining it wrong. They are saying that the light bent. That's not what's really happening. The light doesn't bend relative to the space it's flowing thru. It flows in a perfectly straight line. Gravity has no direct effect whatsoever on light, because light is massless. Gravity only can effect the SHAPE of the spacetime density field. The fact that the spacetime is bent makes it look to us, as if the light changed direction. It didn't. Light passing thru an ordinary optical glass lense DOES bend, but light passing by a massive object in space absolutely does not bend. It merely "looks" like it did.

[lutusp]

> Most physics articles (and even the Wikipedia page on Gravitational Lensing) are explaining it wrong.

Ah, the encyclopedias are wrong. That may be true, but only if you meet your burden of evidence. You cannot meet your burden of evidence, and you show no sign of even trying.

[ClayFerguson]

Oh, I can prove it with evidence. The only thing that can change the direction of motion of a particle is a force. Photons have zero mass and zero charge, therefore no force (including gravity) can act on light (strong and weak interactions are not applicable here). Therefore light will always travel in a straight line. When light appears to 'bend' it is not because the light itself changed direction in its reference frame, but because the space the light is traveling thru in is warped. Any physics professor will understand precisely what i'm saying, and all agree. Someone who has only read a few articles online will not. I've understood this since 1986. I'm very old and wise you little child.

[lutusp]

> The only thing that can change the direction of motion of a particle is a force.

Quite false. You're overlooking the fact that photons are the carrier particle of the electromagnetic field, which takes the form of waves in space -- waves that change direction without the application of forces. An optical lens changes the direction of photons without exerting a force. So does curved spacetime. These are examples of hundreds of things about physics that contradict your outlook.

Also, masses respond to gravity by changing direction, and gravity is not a force: http://curious.astro.cornell.edu/physics/140-physics/the-the...

Again, at 1.5 times the radius of a black hole, looking tangentially, you would see the back of your own head. So even in this local frame of reference, light has taken a curved path along with curved spacetime. In other frames of reference, light is obviously not traveling in straight lines. In fact, it can be argued that light never travels in straight lines -- that would be true only in a universe without any mass at all.

You could argue that water always travels along straight lines inside a pipe and never changes direction, and in the case of the pipe itself changing direction, you could argue that the water is always traveling in a straight line from its own perspective inside the curved pipe, but having said that, people would see your ideas for what they are.

> Any physics professor will understand precisely what i'm saying, and all agree.

You appear to have forgotten I have already disproven this with my John Wheeler quote: "Mass tells space-time how to curve, and space-time tells mass how to move." As with masses, so with photons. If masses could travel at c, they would take the exact path photons do -- curved ones.