[digler999]

the same thing could have been said about the discovery of Neptune [1]: "there's no evidence a planet is there, it's pure speculation. The changes in Uranus' orbit must be the result of mathematical error and not another planet."

[1] https://en.wikipedia.org/wiki/Neptune

[ClayFerguson]

If man had discovered Gravitational Lensing BEFORE Einstein had formulated General Relativity we would have given some name to the effect, and perhaps even considered it a characteristic relationship between stars and light. The relationship happens to be an INDIRECT one. Star mass bends space, and the light merely "appears" to bend, when it traverses that space. It doesn't actually bend.

What I'm saying about Dark energy/matter, is that there is also an INDIRECT relationship there. It's not just a special invisible mass and invisible energy. It's a fundamental misunderstanding about what spacetime is. I think the "dark" quantities are every bit as much an illusion as the "light bending" illusion created by stars.

[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.