Mean longitude

Mean longitude is like having a game with a spinning top. Imagine that the top is spinning and you want to keep track of where it is. But the top is always moving and it's hard to keep track of where it is at every moment. So, what if you average out where the top has been over a period of time? This would give you the mean or average location of the spinning top, despite its constant movement.

The same thing happens with planets and stars in space. They are moving and spinning around constantly, which makes it hard to keep track of where they are at all times. But by calculating the mean longitude, scientists can determine the average location of a planet or star over a set period of time. This helps astronomers predict where the planet or star will be in the future and also provides a better understanding of their movements and patterns.