Two primary theories explain planetary moon formation: gravitational capture within a planet's Hill sphere radius and simultaneous formation with the solar system during its accretion disk phase. A ...

It's all about perspective: The higher you go, the more you can see the curve. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. The answer is all ...

The only way to see the curve of the Earth is to fly more than 6 miles (10 kilometers) above its surface. When you purchase through links on our site, we may earn an affiliate commission. Here’s how ...

To the run of men, the earth seems to rotate with trustworthy steadiness. Astronomers know better. Observed with their sharp-eyed instruments, the earth’s rotation is a wobbly business. In Nature, ...