The Short and the Long

5/21/07 – 5/27/07
by C. Zaitz

I just had one of those milestone birthdays- you know, the ones that are supposed to be more special than the rest because the number is getting so high that you have to celebrate just being alive. It made me think of the age of things. Biologically, things happen on a pretty short time scale. 70-80 years is not that long when you take into consideration how long rocks live. In astronomy we talk about ages of stars, in geology we talk about the ages of rocks and planets. In human lifescales, those numbers are incomprehensible. We have no feeling for how long it takes a rock to form, much less a star. It seems like eternity to wait for your tomatoes to ripen or for your hair to grow out after a bad cut!

Though humans have a relatively short lifespan, we are still around long enough to watch things grow and develop, die and transform. Plants and animals live in our time scale, though we marvel at the 2,000 year old sequoias and ancient cedars. But things we think of as everlasting, like rocks or stars, are not eternal. All rocks move through a cycle, from being sand sediments on the surface, to being metamorphised as the pressure of layers upon layers of rock change its character, to suffering the igneous fate of melted rocks, turning into magma and reforming on the surface as lava basalt, only to be worn away again as sand and sediment. Eons pass and the dirt just keeps changing form, nothing destroyed or created, but morphing from one form to another.

The same thing happens with stars. Our sun was once diffuse gas and dust, our own planet not more than a breath of cosmic debris, sprinkled with rare elements fused in the death throes of an ancestor star. Gravity and pressure brought everything around, and our solar system will go for at least as long as it already has, some 4.5 billion years. Then it will die, only to form something new in the next “billenia.” Will it be something completely different? A double star or part of a new open cluster of stars? Or maybe a familiar life-harboring solar system?

We happen to be living in a very particular time when we as a species can begin to understand all the cycles of life and death around us. How unique and incredible for us. It’s not surprising we’re so curious about the universe, since we see our own selves reflected in the life cycles, in the growing and dying of everything around us. I think we study these cycles to try to understand what happens when we, too, die. Will we be born again in some “next cycle?”

From an old southern banjo tune:
Little birdie, little birdie,
come sing to me your song.
I've a short while to be here,
and a long time to be gone.
Little birdie, little birdie,
What makes you fly so high?
It’s because I am a true little bird
and I do not fare to die.
I guess I like to think that nothing really goes away. We all get older and will all die, but even black holes give up their dead eventually. Nothing seems to be destroyed, and it all comes back around again, sometimes in the near future, like perennial flowers, and sometimes in the long run, like planets with life.

Until next week, my friends, enjoy the view.