Einstein–Hilbert action
The Einstein–Hilbert action is how physicists measure the amount of space and time in the Universe. It is like asking "How much space and time is there in the Universe?"
To answer this question, scientists use the Einstein–Hilbert action. This action measures the amount of energy that comes from the way that space and time are curved together. This action is written in a special form called the "Einstein-Hilbert Action" and it gives us a number to measure how much space and time is present in the Universe.
This action can be used to answer other questions about the Universe too, like what happens when something changes in space and time. By looking at the Einstein–Hilbert action, scientists can figure out how things like gravity and energy work when they change.
To answer this question, scientists use the Einstein–Hilbert action. This action measures the amount of energy that comes from the way that space and time are curved together. This action is written in a special form called the "Einstein-Hilbert Action" and it gives us a number to measure how much space and time is present in the Universe.
This action can be used to answer other questions about the Universe too, like what happens when something changes in space and time. By looking at the Einstein–Hilbert action, scientists can figure out how things like gravity and energy work when they change.