Dozens of extraterrestrial planets without stars, perhaps detected.

Astronomers have spotted other strange "floating" planets that may wander into distant space but are not associated with them.

While we might think that planets need to orbit around some sort of star, astronomers have detected such orphaned "swindlers" before. And a new study is using data from NASA's Kepler Space Telescope to identify more exoplanets that could move freely.

"Kepler has achieved what it was never designed to do, in providing further tentative evidence for the existence of a population of Earth-mass, free-floating planets," co-author Eamonn Kerins, a researcher at the University of Manchester in the U.K., said in a statement.

In the study, which was published July 6 in the journal Monthly Notices of the Royal Astronomical Society, the team used data that Kepler collected during a two-month stint in 2016 during the space telescope's K2 mission phase.

Over this two-month period, Kepler watched a field of millions of stars near the center of our galaxy every 30 minutes. In analyzing this data, the team hoped to see signs of rare gravitational microlensing events, which occur when the gravity of a massive foreground object bends the light of a more-distant star or quasar, acting like a cosmic magnifying lens that allows scientists to see objects that might otherwise be too far to spot.

Over the course of the study, they found 27 short signal candidates of various lengths, ranging from an hour to 10 days.

Some of these signals had already been observed in other ground-based information collected on Earth. However, the data from the four shortest of these microlentil events are consistent with the presence of planets with approximately the same mass as Earth.

If the microlens events spotted with Kepler were to reveal a host star or a star that has planets in its orbit, scientists might expect a longer signal. Therefore, by finding evidence for these planets but without the longer signal typically associated with a host star, the team suspects that the planets could be floating.

It's possible that if these are, in fact, rogue, starless planets, that they may have originally formed around a host star and were pulled away by a gravitational force by a more massive planet or object, according to the statement.

But spotting these signals was no easy feat, especially seeing as Kepler wasn't designed to detect planets using microlensing, and it wasn't designed to study such a crowded field of stars. (Kepler, which was decommissioned in November 2018 after nearly a decade of in-space work, hunted for planets using the "transit method," looking for stellar brightness dips caused when a planet crossed its host star's face.)

"These signals are extremely difficult to come by,' said lead author Ian McDonald, a researcher at the University of Manchester. "Our observations pointed an elderly, ailing telescope with blurred vision at one of the most densely crowded parts of the sky, where there are already thousands of bright stars that vary in brightness and thousands of asteroids that skim across our field."

"From this cacophony, we try to extract the tiny lightning features caused by the planets, and we only have one chance to see a signal before it disappears. This is about as easy as looking for the wink of a firefly in the middle of a motorway, using only a mobile phone,' said McDonald.

To achieve this, the team had to develop new techniques to analyze their data. However, even though their results are impressive and fascinating, they do not confirm the existence of these rogue planets alone. Future observations with missions like NASA's Nancy Grace Roman Space Telescope and possibly also the European Space Agency's Euclid mission, both of which will be able to spot signals of microlensing events, could be used to help confirm the existence of these strange planets, according to the statement.