Last week while on tour, I had a perfect view of the shadow of the earth. Yeah, and I wasn't in outer space or anything!
We were flying from out west to the northeast, and as the sun set behind us, the shadow of the curve of the earth was reflected on the atmosphere above. Unfortunately, I didn't have my camera right there, even if I would have been able to make it work. So here's some pictures of what it looked like, courtesy of http://www.chitambo.com/clouds/cloudshtml/earthshadow.html. Believe it or not, there are still people who believe that the earth is flat!
See this response to a post with a picture of the shadow of the earth (like the above):
Observing Earth's shadow
Well, the "shadow of the Earth's curve" is a nice guess, but I don't think there's anything that can prove that it's actually the Earth's shadow. It could just as well be the sun reacting oddly to the rest of the sky. I mean, we see sunsets all different colors; seeing purple doesn't really prove to me that it's the Earth's shadow.
This is actually a very interesting site. Just go by their FAQ pages for assertations such as:
General / this forum
Q: "Is this site for real?"
A: This site is real. There are members who seriously believe the Earth is flat. However, there are also members who do not.
Q: "Why do you guys believe the Earth is flat?"
A: Well, it looks that way up close. In our local frame of reference, it appears to take a flat shape, ignoring obvious hills and valleys. Also, Samuel Rowbotham et al. performed a variety of experiments over a period of several years that show it must be flat. They are all explained in his book, which is linked at the top of this article.
The stars are about as far as San Francisco is from Boston. (3100 miles)
Q: "Please explain sunrises/sunsets."
A1: It's a perspective effect. Basically, the sun is just getting farther away; it looks like it disappears because everything gets smaller and eventually disappears as it gets farther away.
A2: As the warped light intersects with the earth, a spectator further away is too low to see the light rays that didn't hit the ground and cannot receive light through the Earth.
Q: "Why are other celestial bodies round but not the Earth?"
A: The Earth is not one of the other planets. The Earth is special and unlike the other bodies in numerous ways.