Question

Does the mass and size of the Earth change over time?

Answer 1

The mass and hence size of the Earth will reduce over time.

Explanation:

The Earth will be losing material in terms of atmospheric gases, including water vapour, escaping into space.

A huge volcanic eruption can cause material to be flung high into the atmosphere and maybe escape the Earth's gravity. Rocks from Mars have been discovered on Earth.

All of the spacecraft we send out originally were part of the Earth.

On the other hand material is being added to the Earth's mass in the form of meteorites. In the early period of the solar system the Earth was gaining mass due to large numbers of impacts.

Ultimately the sun will become a red giant and all of the atmosphere and oceans will be lost to space.