Empty Glass

4/16/06 –4/22/06

By C. Zaitz

All my life I’ve looked at the Universe as if it were mostly empty. Blackness upon velvety blackness, interrupted by sprinkles of brilliant diamond stars, on and on with no end to the emptiness. I knew that the Milky Way alone contains hundreds of billions of stars and that it is one of billions of galaxies in the observable universe. It sounds pretty crowded, but the truth is that there is lots of room. One of our nearest neighbors, the Andromeda Galaxy, lies well over 2 million light years from us. Andromeda is home to massive numbers of stars, like the Milky Way, and furthermore, she is headed toward us. Scientists think that in no less than 3-4 billion years, our two galaxies will collide! But there is so much nothing in these galaxies that they can pass right through each other without a single star ever colliding. That’s what I mean by the universe being pretty empty – even the most densely packed regions, the galaxies, are generally made of nothing.

Now astronomers think that the nothing is actually something and that most of the universe is made of this something that looks and feels like nothing: dark matter and dark energy. Together these mysterious dark nothings add up to filling the universe. Though we aren’t clear about the nature of dark energy and dark matter, I’m sure we will figure it out soon. I feel like a paradigm shift is coming, as when people had to stop thinking of the earth as being the center of the universe and admit that we were orbiting a much larger star. Now instead of this vast empty universe, we are in fact apparently embedded in a rich and connected fabric of spacetime whose weft and warp are made of dark matter and energy.

Pete Townshend of the rock band The Who wrote a song called Empty Glass. He said it was an allusion to the fact that you can’t come to the Universal Bar with a full glass and expect to get something in it. You have to have an empty glass. I think he meant that if you want to gain some sort of knowledge or insight you have to have an open mind, not one full of preconceptions. Our conception of the Universe as being empty perhaps distracted us from the fact that it was full of stuff, only it was stuff we couldn’t see. Now astronomers are hard at work looking for the invisible. Some say that dark energy may be a kind of “quintessence” or a vacuum energy of empty space. Dark matter seems to be embedded in the galaxies themselves, giving them more heft and explaining why the spiral arms don’t wind themselves up after a few rotations of a galaxy. I am very much looking forward to the day that we have a better description and explanation for dark matter and dark energy. I’d like to know what the universal glass is full of.

Our evening sky will be peppered with the stars of spring and two evening planets. Mars is still the westerly member of the duet and Saturn hangs high in the south in the early evening. Jupiter rises later in the evening and is best seen starring opposite Venus in the morning sky.

Until next week, my friends, enjoy the view!