(CN) — Rogue planets — planetary bodies not tethered to the gravitational pull of a star — are usually quite tricky to find and only a few have ever been spotted. Astronomers just found about 70 of them.
The free-floating planets have been giving scientists headaches for some time. Adrift in space without a host star to guide them, rogue planets can be incredibly hard to locate due to their nomadic lifestyles, are typically not hot enough to glow by themselves and questions over how they formed in the first place have continued to swirl.
Of the suspected rogue planet sightings in the past few decades, some haven't been officially verified as rogue planets and only one has been found in the Milky Way.
But all that changed when, in a study published Wednesday in Nature Astronomy, astronomers announced they’ve found approximately 70 new rogue planets in a region of space close to our sun — the largest ever group of these cosmic orphans ever discovered, and each one with a mass comparable to Jupiter.
“We did not know how many to expect and are excited to have found so many,” said study author Núria Miret-Roig, astronomer at the Laboratoire d’Astrophysique de Bordeaux, France, and the University of Vienna, Austria, in a statement.
To make this achievement possible, experts took advantage of the reality that rogue planets, only being a few million years old, can’t glow by themselves and are not being illuminated by a host star. While this would normally make them harder to find in the expanse of space, their lack of glow makes them directly observable through powerful cameras on large telescopes.
So this is exactly what astronomers did. The team behind Wednesday’s study used nearly 20 years of data taken from an array of different telescopes both on the ground and in outer space, including the ESO’s Very Large Telescope (VLT) in Chile. The VLT and other instruments from the ESO observatories in particular proved crucial to the effort, given the tremendous breadth of sensitive data researchers had to comb through to make their findings.
“The vast majority of our data come from ESO observatories, which were absolutely critical for this study,” Hervé Bouy, astronomer at the Laboratoire d’Astrophysique de Bordeaux, France, and project leader, said with the study. “Their wide field of view and unique sensitivity were keys to our success. 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.”
On top of bringing dozens of new rogue planets into the fold, experts think the findings might just be the tip of the iceberg. Experts believe there could be billions of other nomadic planets in just our galaxy alone waiting to be tracked down.
Regardless of how many more rogue planets appear on star-searchers’ radars in the future, experts say 70 new discoveries could give scientists some much-needed clues on how rogue planets form in the first place.
Some scientists believe they’re made when a gas cloud, one that is too small to form an actual star, collapses in on itself. Others maintain rogue planets were once members of a solar system and likely formed under typical planet conditions before some chaotic series of events kicked them out of orbit. It is unclear, however, which of these theories holds the most water, and scientists from Wednesday’s study hope that their research could help put others on a path toward answers.
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