December 29, 2013


I chose the #3 story of 2013 because it was one of my favorite science news stories of the year, about a newly discovered planet far from our solar system that is different than any other we have ever seen.



Eighty light-years from Earth, astronomers have discovered a planet that is six times bigger than Jupiter, floating all alone without a sun to keep it warm. Scientists have seen free-floaters like this before, but we have never been sure whether they were planets or stars that had died. This time, we have enough information to be sure it is a planet similar to the "gas giants" in our solar system - Jupiter, Saturn, Uranus and Neptune. These planets are very low in density and consist mostly of hydrogen and helium gases. If you tried to land a spacecraft on Jupiter, for example, it would keep sinking down through the gas, until it would be crushed by Jupiter’s gravity.

The new planet is named PSO J318.5-22, and it is near a group of young stars called the Beta Pictoris moving group, which formed about 12 million years ago. One of the stars in that group is circled by its own gas-giant planet that’s about eight times bigger than Jupiter.

"We have never before seen an object free-floating in space that that looks like this," team leader Michael Liu said. "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."

I don’t think that PSO J318.5-22 is a very good name for a planet, do you? My readers agreed, and some of you wrote in with ideas like "Purple Giant," "Starless 12000000," and "Planet Mega Purple."


Image: An artist’s rendering of PSO J318.5-22 by V. Ch. Quetz / MPIA

Posted by: Seymour Simon

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