Tides: Crash Course Astronomy #8
Today Phil explores the world of tides! What is the relationship between tides and gravity? How do planets and their moons become tidally locked? What would ...
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Y’know, if Shakespeare had been an astronomer, he’d have said that “there is a tide in the affairs of the Universe, and on such a full sea are we now afloat.” He would’ve been right. You might just think of tides as the ocean going in and out every day, but in fact what astronomers call tides are a subtle but inexorable force that have literally shaped most objects in the Universe. And to understand tides, we start with gravity. Gravity is a force, and it weakens with distance. An important thing to note is that we measure gravity from the center of mass of an object, not its surface. One way to think of the center of mass of an object is the average position in an object of all its mass. For an evenly distributed sphere, that’s it’s center. Right now, unless you’re an ast...
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Y’know, if Shakespeare had been an astronomer, he’d have said that “there is a tide in the affairs of the Universe, and on such a full sea are we now afloat.” He would’ve been right. You might just think of tides as the ocean going in and out every day, but in fact what astronomers call tides are a subtle but inexorable force that have literally shaped most objects in the Universe. And to understand tides, we start with gravity. Gravity is a force, and it weakens with distance. An important thing to note is that we measure gravity from the center of mass of an object, not its surface. One way to think of the center of mass of an object is the average position in an object of all its mass. For an evenly distributed sphere, that’s it’s center. Right now, unless you’re an ast...
