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Wish Upon a Star
02/08/09 10:00 AM
You are stardust . . . literally
Like our Sun, stars are the "mothers" of planetary systems. On a clear night far from city lights, we can see only a few thousand with the naked eye, but the cosmos holds an astounding number — by some estimates, more stars than there are grains of sand in all the Earth's beaches and deserts. Closer to home, in our galaxy alone (the so-called Milky Way) there are hundreds of billions of stars, and a new one is birthed every year. So think of it this way . . . if you live an average lifetime, roughly 80 new stars will be born in our galaxy alone during your short tenure on this planet.
So just how do stars come to life, and how often? Current evidence suggests that stars are created when gravity collects and compresses gases and dust floating in interstellar space. When these orbs of gaseous material reach sufficient size and density, nuclear fusion begins, manifesting the Biblical admonition of "Let there be light!" The amount of material in the new star determines, in part, how long it will exist. Our own Sun is expected to have a life span of about 10 billion years, and it is in its midlife right now, or about halfway through.
Recently, astronomers have observed a galaxy much younger than our own, and they have discovered that star formation can occur at much faster rates earlier in the galactic life cycle. They have called their observations "astonishing," pointing out that in certain regions of this young galaxy, as many as a thousand stars may be birthed every year. It is possible, then, that early in the Milky Way's existence, stars were being created at a much more rapid pace.
So the creative force or energy that birthed the cosmos some 14 billion years ago remains very much alive and active. Old stars die all the time, and new ones are constantly being formed — the same cycle of birth, life and death that characterizes human existence. Of course, the matter that makes up our bodies came from the explosions of dying stars billions of years ago. As Joni Mitchell sang, "We are stardust." This is quite literally true.
So when you look up at the night sky, you are observing a dynamic, ever-changning universe that is intimately interwoven with your own existence. You and all those stars are connected. In some sense, you are a wish upon a star.
So just how do stars come to life, and how often? Current evidence suggests that stars are created when gravity collects and compresses gases and dust floating in interstellar space. When these orbs of gaseous material reach sufficient size and density, nuclear fusion begins, manifesting the Biblical admonition of "Let there be light!" The amount of material in the new star determines, in part, how long it will exist. Our own Sun is expected to have a life span of about 10 billion years, and it is in its midlife right now, or about halfway through.
Recently, astronomers have observed a galaxy much younger than our own, and they have discovered that star formation can occur at much faster rates earlier in the galactic life cycle. They have called their observations "astonishing," pointing out that in certain regions of this young galaxy, as many as a thousand stars may be birthed every year. It is possible, then, that early in the Milky Way's existence, stars were being created at a much more rapid pace.
So the creative force or energy that birthed the cosmos some 14 billion years ago remains very much alive and active. Old stars die all the time, and new ones are constantly being formed — the same cycle of birth, life and death that characterizes human existence. Of course, the matter that makes up our bodies came from the explosions of dying stars billions of years ago. As Joni Mitchell sang, "We are stardust." This is quite literally true.
So when you look up at the night sky, you are observing a dynamic, ever-changning universe that is intimately interwoven with your own existence. You and all those stars are connected. In some sense, you are a wish upon a star.