The hunt is on for Planet Nine
By Amanda Jermyn

The hunt is on for Planet Nine! Back in January Caltech researchers Michael E. Brown and Konstantin Batygin inferred the existence of a ninth planet in the far reaches of our Solar System, based on similarities in the orbits of six small distant objects.

Ironically, it was Dr. Brown’s 2005 discovery of Eris, an object comparable in size to Pluto that led indirectly to Pluto being downgraded to a dwarf planet. In 2006, in response to the discovery of Eris and two other Pluto-sized Solar System objects, the International Astronomical Union revised its definition of a planet to require that it “clear the neighborhood around its orbit” of other bodies of comparable size other than its own satellites or moons. As Pluto did not satisfy this requirement, it became known as a dwarf planet, leaving the Solar System with only eight planets.

Based on computer simulations and mathematical modeling, Dr. Batygin and Dr. Brown predicted that Planet Nine would be a super-Earth, with a mass about ten times that of Earth and a diameter of about two to four times that of our home planet. It would have a highly elliptical orbit, ranging from about 20 billion miles from the Sun at its closest to about 100 billion miles away at its farthest. In comparison, Earth is about 93 million miles from the Sun, and distant Pluto, at its farthest, is about 4.6 billion miles from the Sun. It is estimated that one trip around the Sun, which takes 365 days for us, would take between 10,000 and 20,000 years for Planet Nine.

What led the researchers to infer the existence of Planet Nine was the observation of a similar pattern in the elliptical orbits of six dwarf planets far out in our Solar System beyond the Kuiper Belt, a region of icy objects and debris beyond Neptune. All six objects loop outward in the same part of the Solar System and all are tilted at about the same angle. The odds of this occurring by chance are very low, only about 0.007%. Brown and Batygin theorize that it is Planet Nine’s immense gravity that is affecting the motion of these dwarf planets in this particular way.

So if Planet Nine really does exist, where is it, and how can we find it? While the initial research could not predict where in its 10,000 to 20,000 year orbit the planet might be, a more recent French study, co-authored by Jacques Laskar of the Paris Observatory, has narrowed down the search area. By studying data from NASA’s Cassini spacecraft that is currently orbiting Saturn the French team was able to exclude two zones, reducing the search area by 50%. This improves the chances of locating the mystery planet. Dr. Brown has already begun searching, and predicts that he should be able to find Planet Nine within the next five years. Others will almost certainly be searching too.

Join the Springfield Stars Club on Tuesday, April 26th at 7:00pm at the Springfield Science Museum for a talk by Crystal Mengele on “The Solar Probe Plus Mission,” due to launch in July 2018. The mission will investigate the dynamics of space weather, and hopes to answer the question of why the Sun’s corona is so much hotter than its surface. Crystal is a histotechnologist and electron microscopist at Baystate Medical Center. She is the president of the Amherst Area Amateur Astronomy Association and a board member of the Springfield Stars Club. Refreshments will be served, and the public is welcome. The meeting is free of charge for members, with a suggested donation of $2 per non-member.

Also, on Friday, May 6th at 7:30pm, the Stars Club and the Springfield Science Museum will host “Stars over Springfield,” an astronomy adventure for the whole family. Tim Connolly will talk on “How to Take Photos of the Moon with a Telescope.” A fee of $3 for adults and $2 for children under 18 will be charged