A consortium of British universities, the Wide Area Search for Planets (WASP) has discovered its seventeeth planet, aptly named WASP-17.
Collaborating with the Geneva Observatory, the group located the giant planet that is twice the size of Jupiter but has only half its mass- the largest planet discovered to date. And it’s the only planet known to orbit backwards around its sun. Scientists who discovered WASP-17 said that it likely became that way due to a “giant interplanetary game of billiards.”
In a press release, they described the process:
Professor Coel Hellier, of Keele University, remarks: “Shakespeare said that two planets could no more occupy the same orbit than two kings could rule England; WASP-17 shows that he was right.”
David Anderson added “Newly formed solar systems can be violent places. Our own moon is thought to have been created when a Mars-sized planet collided with the recently formed Earth and threw up a cloud of debris that turned into the moon. A near collision during the early, violent stage of this planetary system could well have caused a gravitational slingshot, flinging WASP-17 into its backwards orbit.”
As planets generally evolve out of “the same swirling gas cloud” that creates the stars they orbit, they usually orbit the star in the same direction. The discovery is being lauded as “one of the strangest planets” we know exists. WASP-17 is 1,000 light years away from Earth.