Astronomers Just Discovered 70 New Starless 'Rogue' Alien Worlds

'There could be several billions of these free-floating giant planets.'
Brad Bergan
A composite image of several others furnished by NASA.Aphelleon / iStock

A team of astronomers analyzing data from multiple European Southern Observatory telescopes has just discovered at least 70 new rogue planets wandering through our galaxy, according to a new study published in the journal Nature Astronomy.

Make no mistake: scientists have never seen a group of rogue planets on this scale before, which means we're witnessing history in the making.

The new batch of rogue exoplanets could reveal how they evolve and die

Rogue planets are mysterious and hard-to-find planetary bodies with masses not unlike those found within our own solar system. But of course, the big difference is that they've no host star, and freely float through interstellar space. It is very cold in interstellar space, not to mention dark, which is why very few have been spotted, until now. And the team of astronomers behind the recent study who found at least 70 rogue planets say this is a massive step toward building a better understanding of the origins and eventual fates of these outlandish, black-sheep bodies of the dark abyssal depths. "We did not know how many to expect and are excited to have found so many," said Astronomer Núria Miret-Roig of the Laboratoire d'Astrophysique de Bordeaux, in France, who is also affiliated with the University of Vienna, Austria, and is the first author of the new study, according to a press release.

Rogue planets wander far beyond the dim light of distant stars barely illuminating them, which makes them virtually impossible to image. But Miret-Roig and her team leveraged their knowledge that in the few million years following their birth, these planets remain hot enough to continue glowing, which makes them directly observable via highly-sensitive cameras and giant telescopes. Using this method, the astronomers found at least 70 rogue worlds that have masses comparable to Jupiter's within a star-forming region that's not that overwhelmingly far from our own sun. From our Earthly vantage point, they're located in the Ophiuchus and Upper Scorpius constellations.

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'There could be several billions of these free-floating giant planets'

But to track down such an abundance of rogue planets, the team used data from over 20 years of observations, sourced from multiple Earth- and space-based telescopes. "We measured the tiny motions, the color and luminosities of tens of millions of sources in a large area of the sky," said Miret-Roig in the release. "These measurements allowed us to securely identify the faintest objects in this region, the rogue planets." The telescopes used in this research included the Visible and Infrared Survey Telescope for Astronomy (VISTA), the European Southern Observatory's (ESO's) Very Large Telescope, and Chile's MPG/ESO 7.2-ft (2.2-m) telescope, in addition to several other facilities.

"The vast majority of our data come from ESO observatories, which were absolutely critical for this study," said Hervé Bouy, another astronomer of the Laboratoire d'Astrphysique de Bordeaux in France, who was also the lead scientist of the new research. "We used tens of thousands of wide-field images from ESO facilities, corresponding to hundreds of hours of observations, and literally tens of terabytes of data." While there's much to admire about the new rogue planets, more impressive is what lies in store for modern astronomy. "There could be several billions of these free-floating giant planets roaming freely in the Milky Way without a host star," explained Bouy. The universe is a vast and lonely place. But perhaps not lonely for long.