(March 2, 2018 at 5:44 pm)Banned Wrote: How do we know that there isn't something else in space that bends light?
Water bends light, and in the right conditions you can't visually prove that it is in between the eye and the object.
Is it possible that space is filled with something which isn't percieved by material beings and their material instruments?
While an absense of physical evidence isn't a licence for the imagination, it is presumptuous to say that what is observable is the only truth.
Well, in a sense, that is how we discovered dark matter and how we investigate its properties. Dark matter doesn't interact with ordinary matter or light very strongly (if at all). So in a sense, it satisfies your criteria.
We use the way that dark matter bends light to map out where it is and how much is there. We do that by looking at slight distortions in the way light travels from more distant objects. So, there is a sense in which we are detecting the water just as you suggested.
