What is the difference between a moon and a planet? Trick question! According to scientific definitions, there often isn’t much of a difference at all. That might seem counterintuitive, but it’s true.

Galaxies come in many shapes and sizes, and trying to define them is difficult In keeping with both trend and theme, it’s time to take a step outward—a big step. If you're enjoying this article, ...

Interstellar comet 3I/ATLAS has gone from a faint outsider to one of the most closely watched visitors in the Solar System, ...

What is Perihelion? In the vast expanse of space, celestial bodies follow elliptical orbits around stars, with one point being closer to the star—known as the perihelion. This is the term used to ...

We explore the celestial geometry that explains different kinds of eclipses of the sun and the moon. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it ...

The Oort Cloud, an expanse of icy bodies in the far reaches of our solar system, is shown here in a scene from "Encounters in the Milky Way," a show at New York City's Hayden Planetarium that spawned ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. A collision between ...

New research may shine a light on part of outer space's great mysteries: the Oort Cloud. The Oort Cloud is the name given to a theorized group of potentially trillions of icy objects on the edge of ...

Voyager 1, launched in 1977, has traveled farther than any spacecraft in human history. After more than four decades of silent endurance through space, it now sails beyond the orbit of the outer ...

An accidental discovery might change how we think about one of the most mysterious structures in our solar system. The Oort Cloud, a large expanse of icy bodies revolving around the sun at a distance ...