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It is an established fact that gravity bends space time and therefore distorts light. We know that Dark matter acts gravitationally. So, just for giggles, lets say I had a sphere of dark matter ejected and floating in intergalactic space. Then, shouldn't this sphere be detectable via the way it lenses light coming from galaxies that lie behind it (relative to earth). Similarly, a mass of dark matter within our own galaxy, should be detectable via the way it lenses light from stars that lie behind it ( again relative to earth). Has anything like this ever been observed? And, if not, wouldn't this be evidence that dark matter may not actually exist?

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Then, shouldn't this sphere be detectable via the way it lenses light coming from galaxies that lie behind it (relative to earth). Similarly, a mass of dark matter within our own galaxy, should be detectable via the way it lenses light from stars that lie behind it ( again relative to earth). Has anything like this ever been observed?

Yes, it should do that, and it does. This effect, known as gravitational lensing, is one of the two main pillars of evidence for the existence of dark matter.

A well-known example occurs in the Bullet Cluster, which is actually two colliding clusters of galaxies.

Bullet Cluster

The distribution of excess mass identified by lensing (blue in the image below) differs from the distribution of mass identified by direct X-ray emissions (pink). This presumably means that the dark matter from each of the original clusters passed through the collision unaffected, whereas the two clusters' luminous matter (stars and gas) ran into each other and slowed down.

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