A new planet has been identified in our very own Milky Way galaxy. PSO J318.5-22, which floats through space just 80 light years from Earth, formed a mere 12 million years ago, Science Daily reports. For a planet, that’s practically right out of the womb.
What’s most peculiar about PSO J318.5-22, or PSO for short, is that the planet doesn’t have a host star of its own. Rather, astronomers discovered it traveling unbridled through space.
"We have never before seen an object free-floating in space that that looks like this,” Dr. Michael Liu of the Institute for Astronomy at the University of Hawaii at Manoa explained in a press release. “It has all the characteristics of young planets found around other stars, but it is drifting out there all alone. I had often wondered if such solitary objects exist, and now we know they do."
Scientists from the Institute for Astronomy at the University of Hawaii at Manoa were looking for brown dwarf stars when they happened to spot the free-floating planet. Pan-STARRS 1, or PS1, a survey telescope located on Maui, detected the heat signature of the new planet and identified it as something different than the other objects around it.
Scientists have identified nearly a thousand planets beyond our solar system since the first one was discovered in 1992. According to iScience Times, scientists believe one in six stars hosts an Earth-sized planet.
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But a free-floating planet like the one discovered by astronomers in Hawaii is a rare find. According to Space.com, rogue planets, or “orphan planets,” are often ejected from their solar systems by chance encounters with other heavenly objects. Like a planetary “fender-bender,” the unintended run-in sends one of the planets careening into outer space.
"My sense is that orphan planets could be numerous,” Doug Lin, an astronomer at the University of California at Santa Cruz, told Space.com in 2005. “There's already indirect evidence that Jupiter-sized worlds have been ejected from some of the extrasolar planetary systems we've discovered in the last decade. The clue is that large planets in these systems often have highly elliptical orbits."