In a startling discovery, no less than astronomical, Astronomers from Britain’s Keele University has reportedly discovered a brand new planet 1000 light years away from Earth which is twice the size of Jupiter. What made this discovery so special is due to the fact that this planet, unlike all other planets in the Universe, orbit backwards. Scientist has named this planet WASP-17, reasons unknown.
The discovery has been widely reported and has stirred up considerable interest for Astronomers around the world. Trying to reason out why this planet goes against nature in it’s orbiting habits, experts are banking on the theory that this unusual phenomena might be due to a
“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 quoted, Astronomer David Anderson of Britain’s Keele University during a press release, announcing the discovery.
Astrophysicist Sara Seager from the Massachusetts Institute of Technology agrees that this is indeed “one of the strangest planets we know about” reports the New York Daily News.
The National Post gave a more detailed explanation of WASP-17 but it would take a learned astronomy enthusiast to understand what they are trying to say. Try to understand this if you can.
Giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses but 1.5-2 Jupiter radii, giving a density of 6-14 per cent that of Jupiter. WASP-17b is in a 3.7-day orbit around a sub-solar metallicity, V = 11.6, F6 star.
In a related report, The Planetary Society gave a better prospective in plainer English, though it might still be alien to most of us. Describing the technique used to discover WASP-17 in this article by Amir Alexander, it states,
WASP-17 was first detected through the transit photometry technique by the Wide Area Search for Planets (WASP) consortium of British universities, using the WASP-South camera array in South Africa. But in order to detect its retrograde motion the WASP team needed an assist from planet hunters at the Geneva Observatory, who specialize in radial velocity measurements.
In further elaboration,
According to Darin Ragozzine of the Harvard-Smithsonian Center for Astrophysics astronomers can identify the direction of a planet’s orbit because of slight discrepancies in the radial velocity data when a planet transits a star. Because a star is rotating, one side of it is moving towards (or away) from Earth faster than the other side. During a transit, the planet covers first one side of the star and then the other, causing a slight but measurable shift in the radial velocity readings. If during the transit the star first appears to be moving relatively slowly towards the Earth, but then faster as the transit progresses, then the planet is orbiting in the same direction as the star’s rotation. But if the reverse is the case – as it is for WASP-17 – then the planet is in a retrograde orbit.
The full report of this discovery can be found at http://arxiv.org/abs/0908.1553
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