Nordtvedt effect

The Nordtvedt effect is something that happens when we compare two things that are really big and heavy, like the Earth and the Moon. Even though the Moon is much smaller than the Earth, it still has a big effect on the Earth because it is so close.

Scientists who study these things found that the way that the Earth and the Moon move around each other is affected by something called gravity. Gravity is a force that pulls things towards each other.

The Nordtvedt effect happens when we take into account the fact that the Earth and the Moon are made of different stuff. The Earth is made up of rock and metal, while the Moon is made up of rock and a substance called regolith. Regolith is like dirt or sand that covers the Moon's surface.

Because the Earth and the Moon are made of different things, they are affected by gravity in slightly different ways. This means that the way they move around each other is also slightly different.

Scientists have to be very careful when they study this effect to make sure they get the right measurements. But by studying the Nordtvedt effect, we can learn more about how gravity works and how planets and moons move around each other in space.