View of the Universe distorted by gravitational lensing?

[Smersh]

(The question is "Is our view of the Universe distorted by gravitational lensing?" but I couldn't fit it all into the title field.)

Today, a member at my own site asked the following question in a thread we have running about black holes, so I thought I'd ask it over here:

Shouldn't our view of the universe be so distorted by gravitational lensing that it would be like looking through a diffused screen of gravitational anomalies. Why is it so clear? You would think that with almost infinite points of refractions we would only see a mixed jumble of what is really out there.

Or are we seeing what peers out between the shadows, the creases between?

http://en.wikipedia.org/wiki/Gravitational_lens

Cheers!

 

[MeteorWayne]

Well, in fact the view is distorted by gravitational lensing. However, they key question is how big is the ditortion, and is it significant. In most directions, it is immeasurable small. Very close to the sun, there's a few arc seconds of distortion.

For distand galaxy clusters with dark matter halos it's even smaller.

It's sort of like looking through a window. Is it distorted? Yes, that's just simple phyiscis. No piece of glass is PERFECT so it is filled with dostortions. Is it distorted enough to notice in 99.999999% of the directions you look? No.

Wayne

 

[Smersh]

Thanks Wayne, but have astronomers found a way of measuring the distortion when looking in various directions that you know of? Are we really sure that "what you see, is what you get?" do you reckon?

(EDIT) Oh sorry you said "immeasurably small" so I guess not then ...

 

[MeteorWayne]

Yeah, I think the wondowpane analogy is a good one. Unless you are very close to a significant mass it makes no measurable difference. If it's like a pice of real old glass that's got a bubble in it, you can't detect the distortion.