Some perspective on our place in the universe

My goal while star viewing Saturday night was to learn to locate the Andromeda galaxy, our nearest galactic neighbor. I practiced finding it for over two hours, so I should have it down now.

Telescopes, because they see such a small part of the sky, are of little use in looking at Andromeda. The galaxy stretches across four moon widths in our view. The problem is everything but the intensely-lit core of the galaxy is too dim to see with the naked eye. With binoculars on a dark night, however, the whole thing becomes much more clear.

It was quite a feeling to see that neighboring galaxy not as a faint speck in the distance, but as a well-defined green blur spread across a large part of our sky. I got the the feeling I was looking out a window of our galaxy towards the neighbor's back yard. It was tough to imagine that the light that I saw from that galaxy Saturday night took 2.3 million years to arrive in Tucson.

To give some perspective: If each galaxy were about the size of a quarter, the galaxies would be spread about one foot apart. The known universe, which contains at least 150 billion galaxies, would spread about two miles in every direction.