Coragyps writes:
The closer stars, Sirius for example, don't have any real opportunity for much of anything massive to be between them and us. And they also move over time relative to background stars (and us): only if some unseen mass moved along with them would the parallax - the triangle - stay warped the same way. And then we have thousands of parallaxes on stars out to 100 parsecs or so, and 1) members of clusters have very similar "triangles" and 2) stars whose spectra show them to be very similar are appropriately bright for their trigonometric distances. It would take a very devious gravitational field to make that happen all over the sky.
Is it possible that dark matter could form this devious gravitational field?
I guess my thinking goes something like this. I started reading various books. Hawking, Geeene, Schroeder and a couple of others. Basically I found that virtually nothing that I assumed about matter and the universe were what I had thought. Time isn't a constant, matter is really all about energy, everything is not only atoms but all atoms are particles, particles behave incredibly strangely, this whole universe is maybe a brane or a matrix or a hologram, and so on.
With all these various observations and theories, including again the theory that space and time are illusionary, it just seems to me that maybe all of these measurements that we make in space aren't what they seem either.
I realize that there are no answers to this but I get the feeling that for those who really do understand astro physics that it is likely even more confusing because it appears to me that there aren't any absolutes anymore.
Sorry I got off on a tangent.