Wednesday, April 19, 2006


I have this nerdy trick question that I like to ask people sometimes:

"What's the furthest you can see?"

Usually people assume you mean on the earth, so they'll say a mile or ten miles or whatever. But then I get a smug look and tell them, "Well I can see for about 2 million light years." (OK, I never actually do this because it would be insufferable, but I'm thinking it.)

Even in light-polluted skies, on a clear night you can see the Andromeda Galaxy, which is more than 2 million light years distant. A fact which strikes me as one of those mind-blowing bits of trivia that's so well-known as to have become banal. Which is what gave me the idea for this design:

And then there's the Grand Canyon. In Arizona, your sense of visual distance is easily fooled because the air is so clear, you don't get the usual clues that help you determine distance and scale. For example, we were walking around the Painted Desert and saw some striated mountains in the distance. They looked just like all the other sandy hills you see there, and we wondered out loud how far they must be. After a few more minutes of walking we realized that they were only a few dozen yards away and were in fact, only about 30 feet high!

Similarly, we drove from Canyon de Chelly to Monument Valley. A few miles out of Tuba City, still about 80 miles from our destination, we saw a distinctive mesa in the distance which looked just like the ones you see on postcards from Monument Valley. But we thought, there's no way we could see that from here. We were wrong again.

And don't forget the Grand Canyon. When you're on the south rim, it looks like the north rim is easily a couple of miles away. Come to find out, it's ten miles! And at the Grand Canyon, on a clear night, you can see at least 10 million light years -- NGC 891 in Andromeda is a naked-eye object, if you can believe that.

All I'm saying is that every stargazer should go there once before you die, if only to see what the real sky looks like.

In my experience, that rocky outcrop is the single best place to set up your telescope in the lower 48 states.


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