Dark matter

[Michael Kieth Adams]

If dark matter has gravity, it bends space.  We should be able to see bends in light  resulting from this.  We probably wouldn’t be able to see it, but we might be able to know where it is.

 

[saac]

In theory it would seem so. To be pedantic for a second though , matter does not have gravity - matter deforms spacetime and it's the curvature of spacetime which we know as a gravitational field.  To paraphrase Einstein, spacetime tells matter how to move while matter tells spacetime how to curve.  There is a thought that "dark matter"  - if it does exist  - may  bend spacetime in the opposite way to normal matter -  in effect creating a repulsive field rather than an attractive gravitational field that we are familiar with .   So instead of forming valleys in spacetime it would form hills and mountains.  Gravitational lensing due to dark matter I think, and I may well be wrong here , is already incorporated in our conventional understanding of gravitational lensing by massive objects.  

https://www.nasa.gov/content/discoveries-highlights-shining-a-light-on-dark-matter

 

Jim 

[andrew s]

1 hour ago, Michael Kieth Adams said:

If dark matter has gravity, it bends space.  We should be able to see bends in light  resulting from this.  We probably wouldn’t be able to see it, but we might be able to know where it is.

 

That is exactly how we "observe" it. That is we deduce the existance of dark matter from it's effect on light.  For example we don't  see enough normal matter to explain some gravitational lensing.

Regards Andrew 

[Michael Kieth Adams]

Thankyou!