How Were the Comets Made?
In traditional Hindu mythology, the god Shiva is both creator and destroyer, bringing life and death to the world. It is an odd pairing of talents for a deity, and yet there may be a real-world counterpart in the heavens, an avatar if you will, in the form of comets. Some recent studies suggest that a rain of comets in the very early history of our planet, perhaps 4 billion years ago, may have seeded the young Earth with complex organic molecules from space—key ingredients necessary for life to arise. On the other hand, giant comet impacts may be responsible for some of the major extinction events in the history of life on Earth, including the demise of the dinosaurs 65 million years ago. Comets, it seems, may have been both creators and destroyers in our own history. Yet the comets have a history of their own, and the more we find out about them the more enigmatic they seem. Although it has been said that “a comet is as close to being nothing as something can be”—in reference to the d
