Credit: by Karl Tate, Infographics artist
Well, it seems NASA, and significant others, are getting serious about Planet Nine, a conjectured yet unseen entity that perturbs the solar system is specific and subtle ways.
Astronomers are trying to take the measure of Planet Nine before the hypothesized world has even been discovered.
Earlier this year, astronomers Konstantin Batygin and Mike Brown, both of whom are based at the California Institute of Technology in Pasadena, proposed that a large planet lurks undetected in the outer solar system, far beyond Pluto's orbit.
Batygin and Brown didn't spot this prospective Planet Nine; rather, they inferred its existence based on the orbits of a half-dozen objects in the Kuiper Belt, the ring of icy bodies beyond Neptune. [Planet Nine: The Evidence for a New Giant Planet in Pictures]
These objects' orbits suggest that Planet Nine may be about 10 times more massive than Earth, and may circle the sun at an average distance of 600 astronomical units (AU) or so, Batygin and Brown said. (One AU is the average distance from Earth to the sun — about 93 million miles, or 150 million kilometers.)
Astrophysics professor Christoph Mordasini and his Ph.D. student Esther Linder, both of the University of Bern in Switzerland, assumed that Planet Nine — if it exists — is basically a smaller version of the "ice giants" Uranus and Neptune, with an atmosphere dominated by hydrogen and helium.
The duo then calculated that such a 10-Earth-mass Planet Nine would be about 3.7 times wider than our planet, with a surface temperature of minus 375 degrees Fahrenheit (minus 226 degrees Celsius; 47 degrees Kelvin).