More Than 70 Rogue Planets Discovered in the Milky Way

by Victoria Santiago

Astronomers have found at least 70 rogue planets. This is the largest group of rogue planets that have ever been discovered. In addition to the 70 orphan planets, 170 candidate planets were also found. These planets were found in a star-forming area near the Sun. To find them, astronomers used data from multiple telescopes all over the world.

The first rogue planet was found while scientists were looking for exoplanets. When looking for exoplanets, astronomers follow a process. They wait for a star’s light to dip. The light reflects when a planet is traveling close to the star. In 2009, NASA launched the Kepler space telescope. They used it with the hopes of finding Earth-like planets orbiting other stars. Instead, in 2012, they found a free-floating planet about 100 light-years away.

That planet, Planet CFBDSIR2149, was the first rogue planet to be discovered. Its location relative to us made it easier to learn more about why this happens.

To find free-floating planets, astronomers use microlensing. To do this, an object in the background is used as a magnifying lens when something in the foreground moves in front of it. By doing this, light is bent in a way that can reveal how big the object is.

These 70 new planets are a culmination of two decades worth of data. Astronomers used a combination of ground-based and space-based telescopes. Some of those telescopes include the European Space Observatory’s Very Large Telescope, located in Chile, and the European Space Agency’s Gaia satellite. Tens of thousands of images were also used. The data showed millions of sources, of which scientists studied motion and luminosity.

What Are Rogue Planets?

Rogue planets float around the galaxy. They’re not bound to any star. They can also be called free-floating, nomad, or orphan planets. There’s no telling how many actually exist in our galaxy. They’re hard to find because they don’t have any light of their own, nor do they travel consistently in front of stars. We don’t know much about rogue planets as a whole, but hopefully, that will soon change.

Scientists theorize that there could be multiple ways orphan planets are created. They could’ve been created the same way that stars are – with clouds of dust and gas. In that case, they would just exist on their own without ever being pulled into a star’s orbit. Another idea is that they were once part of a solar system and somehow got ejected. Regardless, they move about the galaxy in the same way that stars do.

With this new batch of nomad planets, scientists hope to discover more about why they exist and how they get here. Many of them are far away and hard to see. While we now know they exist, we have to upgrade our technology in order to see and understand them better.