Just what is Planet 9 made of, and it is any danger to us on Earth? Those are the questions swirling in the media two months after scientists first reported on proof of the mysterious planet's existence.
The evidence for the existence of Planet 9 has been steadily mounting since Caltech astronomers Konstantin Batygin and Mike Brown released a research paper published in January by the Astronomical Journal. In it, the Caltech researchers detail their evidence that a giant planet, dubbed Planet 9, is circling the Sun in an elongated, wobbly orbit in an area called the outer solar system. They believe Planet 9 would have a mass about 10 times greater than Earth's and that its bizarre orbit would take it about 20 times farther from the Sun than Neptune. They say that Planet 9 would take between 10,000 and 20,000 years to make one orbit around the sun.
Unlike Pluto, recently reclassified as a dwarf planet, Planet 9 has a much greater gravitational force. The Caltech researchers used mathematical models to prove their theory and note that the presence of Planet 9 and its gravitational field would explain some of the features of the Kuiper Belt, a range of frozen objects that exists beyond Neptune in our solar system.
As mentioned in an article in Universe Today, the gravitational pull of Planet 9 may also explain mysterious irregularities in the orbit of NASA's Cassini space probe.Christoph Mordasini, a professor at the University of Bern in Switzerland, and his Ph.D. student Esther Linder were intrigued by the putative existence of Planet 9 as outlined by the Caltech team and decided to try to find answers to the questions that possibility raised. What would Planet 9 be made of? What would its temperature be, and how can we view it directly?
The astrophysicists specialize in modeling planetary evolution based on using images of faraway objects. Making assumptions based on what we already know about planets like Uranus and Neptune, they calculated Planet 9's current state. With a mass 10 times that of Earth, it is almost four times larger in terms of radius measurement, with a very cold surface temperature of minus 226 degrees Celsius.
The Swiss researchers aren't the only ones curious about mysterious Planet 9. According to the Mirror, an astronomer from the Lund Observatory in Sweden believes that Planet 9 is actually an alien planet from another solar system that somehow became locked in its wonky orbit around the Sun. Alexander Mustill is an astronomer and one of three researchers in a paper titled "Is there an exoplanet in the Solar System?" published in the journal Astrophysics in March.
"While the existence of Planet 9 remains unproven, we consider capture from one of the Sun's young brethren a plausible route to explain such an object's orbit."
The researchers theorize that the "capture" of Planet 9 may have occurred during the early days of our Solar System when the Sun was part of a cluster of galaxies. As planets began to form orbits around each star, there may have been some planetary traffic incidents that led to Planet 9 being knocked off its path and into an eccentric orbit around the Sun.
According to the New York Post, Daniel Whitmire at the University of Louisiana thinks Planet 9 could have been responsible for a wave of extinctions on planet Earth thousands of years ago and will do it again when it passes by on its wonky orbital path. Going by the record left by fossils, it appears that waves of extinction have occurred about every 26 million to 27 million years. Whitmire believes that as Planet 9 passes by Earth, its gravitational pull generates a series of comet showers that he calls "extinction events." In fact, some people believe that will occur later this month.How much weight should you put into the doomsday predictions? Twitter users had a field day with the news. Scientist Mike Brown answered the controversy directly. How can any of the theories be proven? Planet 9's core is still cooling, according to the model developed by the Swiss researchers, meaning it is warmer inside the frozen layers of helium and hydrogen. The surface of Planet 9 does not reflect a great deal of sunlight. That theory would explain why Planet 9 has not yet been viewed by telescopes based on Earth -- it's simply too dark and too far away.
They note, however, the possibility that NASA's Wide-field Infrared Survey Explorer, which records in infrared light, may have recorded evidence of a planet about five times larger than current theories about Planet 9 at about 50 times the mass of Earth. They believe that the next generation of telescopes, like the Large Synoptic Survey Telescope being built in Chile, should be able to view Planet 9.
[Image via Esther Linder, Christoph Mordasini, Universität Bern]