Image Credit: TheDigitalArtist / Pixabay

As Many as 50 Billion Rogue Planets May Exist in the Milky Way Galaxy Alone

Around 50 Billion free-floating-rogue planets exist in the Milky Way alone. There are around one hundred billion galaxies in the observable universe.


Astronomers now believe that at least 50 billion rogue planets travel our galaxy without a sun.

Nearly three decades ago, astronomers were unsure whether or not distant alien stars had any planets orbiting them. Then, during the 1990s, we discovered the first exoplanets, and astronomers knew that our sun was not that special after all. But what about planets that do not orbit any known stars, and what about rogue worlds that travel the cosmos freely? These worlds may not be so rare, even though, to date, astronomers have discovered only a handful of them.


But a new study by scientists from the University of Leiden suggests that there may be as many as 50 billion rogue planets in the Milky Way alone. That’s a Billion. This number shows you how humongously large the universe we live in is. Using a computer simulation, scientists from the University of Leiden focused on around 1,500 stars in the Orion Trapezium, a well-known star formation region located some 1,300 light-years away in the Orion Nebula.

We have no idea the number of worlds that orbit stars there, but scientists’ models included four and six planets. The researchers assigned 500 stars to a different number of planets. Some were given 4, some 5; some were given six each, totaling 2,522 alien worlds. Their masses ranged from three times that of our planet to as much as 130 times the mass of Jupiter. Scientists discovered that of the total of 2,522 planets, 357 of them would become free-floating planets within the first 11 million years of their evolution.

Simon Portegies Zwart, an astronomer at the University of Leiden, recently told Bruce Dorminey of Forbes: Of these, 281 leave the cluster, others remain bound to the cluster as free-floating intra-cluster planets. But scientists wanted to find out the larger picture. They extrapolated those numbers to the rest of the galaxy, using a starting point to estimate that there are around 200 billion stars in our galaxy alone. If the Milky Way stars have lost one or more planets, there could be at least some 50 billion free-floating alien worlds in the Milky Way. And that’s just in our galaxy alone. According to the best estimates of astronomers, there are at least one hundred billion galaxies in the observable universe.


Join the discussion and participate in awesome giveaways in our mobile Telegram group. Join Curiosmos on Telegram Today.

Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

Write for us

We’re always looking for new guest authors and we welcome individual bloggers to contribute high-quality guest posts.

Get In Touch