Astronomers discovered up to 170 “rogue” planets that are similar to Jupiter, located in a group approximately 420 light-years from Earth. This is the largest known group of their kind. 

These planets are lurking in the dark universe, with no star to illuminate them, and are normally impossible to image, according to astronomers from the Laboratoire d’Astrophysique de Bordeaux.

The fact that these giant gas worlds still glow a few thousand years after their formation made them easily detectable. 

Their remarkable discovery was made using multiple observatories, such as the European Southern Observatory Very Large Telescope, (VLT), in Chile. 

‘We did not know how many to expect and are excited to have found so many,’ explained study author Núria Miret-Roig, adding that they were in a star forming region in the Upper Scorpios and Ophiuchus constellations.

This image shows a small area of the sky in the direction of the region occupied by Upper Scorpius and Ophiucus

This is a view of a tiny area of sky that faces the Ophiucus and Upper Scorpius regions.

What is a ROGUE PLANET? 

These rogue worlds are sometimes called orphan, bound and nomad.

They are interstellar object that have the same dimensions as a star, but they aren’t bound to either a parent star or a host star.

They can have many causes, from being born in small clouds of gas or dust to being sent from a star system into space.

There may be billions or trillions of planets that are not in the Milky Way.   

For the discovery of so many strange planets, the team used data over 20 years, both from space-based and ground telescopes. 

Miret Roig explains, “We measured the small motions, colours, and luminosities from tens of million of sources over a large area in the sky.” 

“These measurements have allowed us to securely identify the faintest objects within this region, the Rogue Planets.”

The majority of the data were obtained from ESO monitored observatories, which included the Very Large Telescope (VLT).

Other instruments including the Visible and Infrared Survey Telescope for Astronomy (VISTA), the VLT Survey Telescope (VST) and the MPG/ESO 2.2-metre telescope.

‘Their wide field of view and unique sensitivity were keys to our success,’ explains Hervé Bouy, an astronomer at the Laboratoire d’Astrophysique de Bordeaux, France, and project leader of the new research. 

“We used thousands of ESO wide-field images, which corresponded to hundreds of hours worth of observations and literally tens terabytes in data.

Team also used the European Space Agency Gaia satellite to pinpoint areas for study. It was launched in order to measure distances, positions and motions stars with unimaginable precision.

Their findings suggest there could be many more of these elusive, starless planets that we have yet to discover. 

Bouy claimed that there may be many billions of such giant, free-floating planets in the Milky Way.

Astronomers can find information about the formation of these worlds by locating as many as they are possible.

This artist's impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background

The artist’s impression depicts a example of an rogue planet, with the Rho Ophiuchi clouds visible in the background


Because they are unable to measure the mass of the probed objects, it is impossible to estimate the number of rogue worlds the team has found.

Jupiter and Jupiter 13-times larger are likely to not be considered planets.

Researchers used their expertise to estimate the limit of detected planets by analysing their brightness.

As a result, brightness and age are related. The brighter a planet gets, the more it dims as it cools.

If the region being studied is an older one, the most bright objects are more likely to be above 13 Jupiter masses. However, if the area is younger it will probably be below 13.

Because of uncertainties in the age, the method gave an estimate of the number of rogue planets between 70 to 170. 

Others believe that stars form when a small-sized gas cloud collapses, while others think they are formed from being kicked from a Star System.  

The authors explain that technology advances will unlock the mysteries of these nomadic planets.

Because the scientists can’t measure the mass of the probed objects, it is impossible to know the exact number. Future observatories may be better. 

Most likely, objects with masses greater than 13 times that of Jupiter will not be considered planets. 

Unfortunately they did not have mass values so they had to use the brightness of the sun to limit the number of planets that they saw.  

In turn, the brightness of planets is related to their age. As such, the brighter a planet becomes, the longer its cooling and decreasing brightness.

According to the team, if the study region is very old then brightest objects will likely be higher than 13 Jupiter masses. However, if it is young, these brightest objects could fall below the age limit.

“Given uncertainties in the area’s age, this method provides a range of 70 to 170 rogue planet counts.” 

When the ESO Extremely Large Telescope, (ELT), replaces the VLT in the next decade, they hope to continue their study.

This image shows the locations of 115 potential rogue planets, highlighted with red circles, recently discovered by a team of astronomers in a region of the sky occupied by Upper Scorpius and Ophiucus

The image below shows the potential locations of 115 rogue satellites. They are highlighted in red circles and were recently found by an astronomer team working in the region of the sky that is occupied by Ophiucus and Upper Scorpius.

Bouy states that these objects “are extremely faint” and cannot be studied with the current equipment. However, he adds, “The ELT will absolutely be essential to gather more information about most of our rogue planets.” 

US scientists have found evidence that the Milky Way might contain over 100 billion extra rogue worlds.

It will be the first to count them with The Nancy Grace Roman Space Telescope, which is scheduled for launch in 2027. This telescope will likely be 10 times more sensitive than existing ground-based telescopes to detect these objects.

The research was published in Nature Astronomy’s paper “A rich population free-floating stars in Upper Scorpius”  


European Southern Observatory (ESO), constructed the largest telescope to be built in Chile’s Atacama Desert.

This telescope is known as the Very Large Telescope (VLT). It is widely considered to be one of the best optical instruments ever created.

It consists of four telescopes, whose The main mirrors are 27 feet in diameter (8.2 meters)

Additionally, there are four six-foot (1.8 metre diameter) movable auxiliary telescopes.

Large telescopes are known as Antu, Kueyen and Melipal. 

The European Southern observatory (ESO) built the most powerful telescope ever made in the Atacama Desert of northern Chile and called it the Very Large Telescope (VLT).

European Southern Observatory (ESO), built the strongest telescope in northern Chile’s Atacama Desert. It was called the Very Large Telescope (VLT) by the European Southern Observatory (ESO).

On April 1, 1999, the first Unit Telescope, named ‘Antu,’ began routine scientific operation.

You can combine the telescopes to create a gigantic ‘interferometer.

The interferometer filters images for unnecessary objects, so astronomers are able to see detail up to 25x better than individual telescopes.  

It has been involved in spotting the first image of an extrasolar planet as well as tracking individual stars moving around the supermassive black hole at the centre of the Milky Way.

Also, it observed the glow of the most distant Gamma Ray Burst.