re: The case against dark matter

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Are you saying that we should see a ring because a star is passing behind the black hole relative to our view of it? If so, we don't because the distance between the star and the blackhole and the size of the star relative to the black hole.

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Objects a massive as a blackhole, and this one is a supermassive blackhole, should have a large gravitational field, or a large "warping of spacetime" surrounding it. That should be sufficient enough for some gravitational lensing to occur.

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As with the proof of general relativity by Sir Arthur Eddington in 1919, the black hole is bending the path of the star's light so that we "see" it before it's actually clear the of the black hole from our viewpoint.

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So you're saying we are seeing the effects of gravitational lensing, but there is no ring? Why is there no change then? Why doesn't the star's image jump or have some kind of effect when it passes near the black hole? If general relativity is correct we should see some visible change.

According to general relativity, we should see this:



or at least some form of phenomena from the light being bent by spacetime's "warping"

But we don't. And there's a simple explanation for it if you use simple science:

There is no atmosphere or anything around the black hole to refract light.

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Recall that Eddington used a solar eclipse to show that a star could be seen even while the sun was between the star and the viewer.

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That test, as with other examples of "gravitational lensing" can be deduced to refraction, yet again. The sun emits a whole hell of a lot of plasma and light will be bent travelling through it.

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This is actually the same effect as lensing but no ring is seen because the object being observed is not big enough for the effect to be realized.

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That makes no sense in regards to general relativity. There should be lensing. The size of the star shouldn't matter. Lensing should happen from any light source passing by or behind any source of gravitational "warping" of spacetime.

Nasa says they can see a distant galaxy with an Einstein ring like this:



In terms of scale that's actually a smaller object (galaxy) behind a much larger cluster of objects (galaxy cluster) at a much further range and they say they'll get lensing due to the massive "warping" of "spacetime" around this cluster.

But we can't see any lensing when there's a much closer object (star that orbits the center of our own galaxy) orbiting an object with far more mass than it (supermassive blackhole Saggitarius A*) that would have an immense "warping" around it, but we can't see it because the star is too small?

Get out of here with that.

If general relativity is correct we should ALWAYS see Einstein rings. In fact, there's so many stars behind other stars or other celestial bodies that actually looking into deep space would be incredibly difficult because of how distorted it all would be. But we don't, It's incredibly rare to see this phenomena.


Later this year that little star orbiting the black hole that we shouldn't be able to see an Einstein ring from is passing near it again. Everyone is going to be looking at this little guy. If there's no Einstein ring, I'm sure they'll use your explanation. If there is, I'll gladly come here, find you, and eat crow, and change my views.