If the moon creates the tides, why don’t any other objects get lifted by its gravitational pull?
In: Planetary Science
They do get lifted in that they get a little lighter.
But they don’t get lifted ENOUGH to completely overcome Earth’s pull.
Gravity is a force that’s very very strongly affected by distance. The further away something is, the less gravity you will be subjected to from it.
The Earth is very massive and very close. Its gravity is immense.
The Moon is much less massive and not nearly as close. Its gravity is honestly pretty tiny.
But that gravity is pulling on EVERY SINGLE molecule of water in the ocean, and that’s enough to make ALL those molecules want to shift the tiniest tiniest bit toward the moon. And because the ocean is a liquid, these molecules can move around individually. So one pushes on another and that pushes on a third and that pushes on a fourth and… and so on and so on. Gigantic stupidly big numbers of molecules of water all want to move toward the moon, they CAN because they’re a liquid, so they create pressure, and the built-up pressure creates tides.
But you won’t see that in a puddle or a pond or a small lake…. there’s just not enough individual water molecules to add up to any sort of shifting pressure. And anything solid? Not affected, really, because the individual molecules in it can’t move individually. They’re locked in place.
There’s other factors. Air itself also gets pulled toward the moon a tiny bit and that removes some of the pressure on the ocean, for example. But in general it’s because the ocean is just so so so vast and is a liquid that it can create visible changes in water levels near coasts.
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