Here's why:

* Gravity is a fundamental force of nature. It's what holds us to the Earth, keeps the Earth orbiting the Sun, and shapes the structure of galaxies.

* Everything with mass has gravity. The more mass an object has, the stronger its gravitational pull.

* Even small things have gravity. You, your phone, a grain of sand – they all exert a tiny gravitational force.

So, from the smallest particles to the largest galaxies, everything in the universe is affected by and contributes to the universal force of gravity.