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How Did Dinosaurs Have Sex?
This Dinosaur Survived the Mass Extinction!
Around 65 million years ago, a comet slammed into Earth, sending a giant death plume of debris into the atmosphere, and killing almost all life including most of the dinosaurs. This is the most popular theory on why dinosaurs became extinct because scientists have tons of evidence to support it, including a huge crater in the middle of the Yucatán Peninsula. But what sent that comet hurtling to Earth in the first place? Geophysicists like Michael Rampino from New York University, have been noticing something strange in the fossil record: every 30 million years or so, there seems to be a mass extinction on Earth. While some extinctions seem to have been larger than others, but most of the big five mass extinctions match up with this timeline. What is causing these extinctions to be happening on Earth with such regularity? Some scientists think the answer might be dark matter.
Dark matter is the strange mass of something in the universe that no one's been able to detect directly, but exerts a strong gravitational force on objects around it. By some estimates, 85 percent of the universe is made up of dark matter. Theoretical physicist Lisa Randall suggests in her new book "Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe" that dark matter might be responsible for sending comets to Earth. Her theory is based on the idea that there is dark matter concentrating near the center of the Milky Way, forming a thin and dense cloud. Randall theorizes that it's a disk made up of particles one hundred times larger than a photon. As our solar systems moves through this disk of dark matter every 30 million years or so, it bobs up and down. The gravitational tug of passing through this dark matter cloud would affect planetary bodies in our own solar system, and could even knock comets and asteroids loose from their orbit in the Oort cloud around the outer Solar System, sending them towards Earth. And maybe this was the case for the comet body that slammed into Earth 65.5 million years ago causing the K-T extinction that killed most of the dinosaurs 65 million years ago.
Fact or Fiction?: Dark Matter Killed the Dinosaurs (Scientific American)
"Every once in a great while, something almost unspeakable happens to Earth. Some terrible force reaches out and tears the tree of life limb from limb. In a geological instant, countless creatures perish and entire lineages simply cease to exist."