Absolute space and time
Okay, so imagine you and your friends are playing tag, and you need to find the best place to hide. You might say "let's go hide behind the big tree!" But how do you know which tree is the "big" tree? Well, you compare it to the other trees in the area.
That's kind of like what scientists used to think about space and time. They thought there was a special, absolute space and time that everything else could be measured against. Sort of like a giant ruler or clock in the universe.
But now we know that's not quite right. See, in the same way you had to compare trees to decide which one was big, we have to compare different things to measure space and time. For example, we might say "that car is going 50 miles per hour." But we can only say that because we know what a mile is (a certain distance) and what an hour is (a certain amount of time).
So, space and time are not these absolute things on their own. They are relative, meaning they depend on what we're measuring and how we're measuring it. And that's the ELI5 version of absolute space and time!
That's kind of like what scientists used to think about space and time. They thought there was a special, absolute space and time that everything else could be measured against. Sort of like a giant ruler or clock in the universe.
But now we know that's not quite right. See, in the same way you had to compare trees to decide which one was big, we have to compare different things to measure space and time. For example, we might say "that car is going 50 miles per hour." But we can only say that because we know what a mile is (a certain distance) and what an hour is (a certain amount of time).
So, space and time are not these absolute things on their own. They are relative, meaning they depend on what we're measuring and how we're measuring it. And that's the ELI5 version of absolute space and time!
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