I was alerted to this by a post on the Bad Science forum. There
one of the posters had used the position of Barnard’s Star to
estimate the date a Google Sky image had been taken. Barnard’s
Star has the highest proper motion of any star known. This means
it moves across the sky compared to background stars. Looking at
the image I wondered why Barnard’s star appeared only once as a
single, very blue image. These colour images are made by
combining images of the sky taken in different colour filters.
These images are often taken years apart so for an object such
as Barnard’s star which moves very fast across the sky the
positions in each filter will be different. Hence you would
expect to see one blue, one green and one red image in three
different positions, this doesn’t appear to happen. I decided to
check out a few other high proper motion stars to see what they
looked like. Proxima Cent is a bit weird, I can’t seem to
identify it on the image, perhaps it is the blue thing on top of
a background star, there i