[Discovery News] As astronomers track down more clues as to the existence of a large world orbiting the sun in the outer fringes of the solar system, a classic planetary purveyor of doom has been resurrected as a possible trigger behind mass extinctions on Earth.Yes, I’m talking about “Planet X.” And yes, there’s going to be hype.
Before we dive into comet impacts, extinctions and possible exciting planet discoveries, let’s look at the dramatic history of Planet X.
At the turn of the 20th Century, astronomers were trying to track down massive planets in the outer solar system using a neat trick of planetary discovery that had already been developed by studying the orbits of known planets to see if they display any strange anomalies.
In 1846, Neptune was discovered in this way after French mathematician Urbain Le Verrier and British mathematician and astronomer John Couch Adams independently calculated the precise location of the planet by looking at orbital perturbations in Uranus’ orbit. The gravitational bulk of Neptune was intermittently tugging on Uranus, producing anomalies in its motion. Naturally, when Neptune was known, astronomers tried that trick again by precisely following Neptune’s orbit. Anomalies were found and the hunt for yet another as-yet-to-be-seen massive planet was on. This was the original hunt for Planet X.
When Pluto was discovered in 1930 by US astronomer Clyde Tombaugh, it was thought the distant world was another massive planet. However, over the years, it became clear that Neptune’s orbital perturbations were down to observational error and Pluto was actually a planetary lightweight and could have no gravitational influence over Neptune’s orbit — a factor that contributed to its re-classification as a dwarf planet in 2006 by the International Astronomical Union (IAU).
Although many more small objects have been discovered in the solar system’s hinterland (a region known as the Kuiper belt), evidence for a massive world has been wanting. The hunt for a massive Planet X pretty much ended with the discovery of Pluto.
But the mysteries of the outer solar system kept beckoning scientists and conspiracy theorists alike. Some oddities in the distribution of Kuiper belt objects, for example, appeared to hint at a massive object slowly plodding in an orbit beyond Pluto. Also, by studying the paleontological record of Earth, our planet appears to have been impacted by quasi-periodic mass extinction events. Could an undiscovered planetary body be rampaging through the Kuiper belt (or even the more distant Oort cloud), destabilizing the orbits of comets, which are then sent hurtling into the inner solar system causing all kinds of havoc to life on our planet every few million years? Read More