At the end of the 18th century, the British scientist Henry Cavendish measured the force of gravity between two objects for the first time in a laboratory. The objects in question were lead balls, one ...

It's fun to think about how we know stuff. For instance, the sun has a mass of about 2 x 10 30 kilograms. That is such an enormous mass that it's difficult to comprehend. And if it's so difficult for ...

There are quite a few fundamental constants. These are things like the speed of light (c) the charge on an electron (e), and the Planck constant (h). These constants are determined with some type of ...

Of the four fundamental forces, gravity is the one we’re most familiar with in our everyday lives, but perhaps surprisingly, it’s the weakest and hardest to measure here on Earth. Now, physicists in ...

Legend has it that Isaac Newton had the moment of inspiration that would lead to his theory of gravity when, on a warm ...

In any direction! The distance between the Earth and the Sun is a careful balance between the mass of the Earth, the mass of the Sun, the speed with which the Earth orbits the Sun, and the strength of ...