Q&A: General Astronomy and Space Science

Q:
As the planet Earth is accumulating meteoric dusts in tons every day, will not the mass of the Earth increase? If so, does it affect its spin? Does the gravity get affected?

A:
You are right, as dust from the cosmos falls on the Earth, the Earth does gain mass. Even the tiniest particle of dust will cause the Earth's mass to increase very slightly. And spin does depend on the mass of the object that is spinning.

However, the mass of the Earth is so great compared with the mass of dust falling onto it that this change is negligible. It is hard to imagine how large the numbers are that describe astronomical bodies, including our planet, but they are so big that even several thousand tons of dust per day has almost no effect on the object as a whole. For the record, the mass of the Earth is approximately 5.97 times 1024 kilograms - remember that one million is 1 times 106, so the mass of the Earth is measured in millions of millions of millions of millions of kilograms.