It’s not hard to find meteorites along Lake Michigan’s Left Coast. After all, they fall to Earth all the time, and some wash up on the nearest beach. This Martian meteorite retains evidence of its fall—one can almost hear the “crack!” it must have made upon impact.
Meteorites are fascinating relics of a universe in transition. They are also the most important clues in determining Earth’s exact age.
One of war’s legacies is the technology of weaponry. Sonar is the method of bouncing sound waves off underwater entities to determine their distance from the sound’s source. In WW2, the technology became the best way to locate innovative German weaponry: submarines. Sonar quickly advanced to a technology far better at mapping ocean floors than anything previously. After the war, scientists sailed the seas with sonar devices.
Plate tectonics had been something of an arcane theory before the mid-20th century. What sonar-wielding scientists learned about ocean floors after WW2 supported the theory. In the 1950s and following decades, plate tectonics became accepted science. Put simply, the theory states that Earth’s surface is made up of hard, crusty pieces—plates—that float on the liquid rock below them. The plates move around, bang into each other, spread apart from each other, creep from north to sound and back again.
When plates collide, one is forced over the other. Rock from the bottom plate is recycled into Earth’s mantle. Over billions of years, little to none of Earth’s original crust remains on the surface. And how would geologists know where to look for it? These facts made determining Earth’s true age difficult.
Astrophysicists explain how the universe formed. They discovered how our solar system was created—the inner rocky planets, the outer gaseous planets, and among them, asteroids and meteoroids. Our solar system formed in a continuous chain of events.
Since the beginning of human history, we have observed rocks falling from the sky. When these meteorites fall in a place like the sandy void of the Sahara Desert, they easily stand out. We are reasonably sure they are in fact meteorites.
Here’s how meteorites tell us how old Earth really is. Let’s assume those meteorites formed at the same time as Earth. If we know their age, we also know Earth’s age. D’oh! Meteorites are rock-hard pieces of evidence that tell us Earth is 4.567 billion years old.
About the Author
Elizabeth G Fagan is an artist, photographer, and writer. A former Chicagoan, Fagan resides in southeastern Wisconsin. She calls her place in the world Lake Michigan’s Left Coast.
Fagan attended a private arts high school on Connecticut’s Long Island Sound, where she focused on print-making and photography. She went on to acquire a BA in English (Grinnell College & UIC), an MA in Linguistics (UIC), and a certificate in web development (DePaul University). A career in Chicago-area publishing and website design/development gave Fagan advanced professional skills. Following a move to Wisconsin, Fagan devotes much of her time to making art. She’s held part-time sales positions with paint, home-design, and photography retailers.
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