space

Astrophysicists John Matese and Daniel Whitmire of the University of Louisiana at Lafayette believe they may have discovered a new planet in our solar system.  Nicknamed Tyche, the object is believed to be the size of four Jupiters, comprised of helium and hydrogen, and orbits our sun at a distance of 15,000AU (one AU, or Astronomical Unit, is the distance from the Earth to the Sun, 15,000AU is roughly 1/4th of a light year).  This orbit puts it well within the boundaries of the Oort Cloud — a cloud of debris orbiting our sun with a radius of one light year — where long-term comets (those with an orbit greater than 200 years) originate.

Matese and Whitmire first proposed the existence of Tyche in 1999 as a result of studying the origins of long-term comets.  It was discovered that their orbits originated in a cluster that was roughly the same angle from the ecliptic, or the path of the Sun through space.  An object at least the size of Jupiter in the Oort cloud could explain the disruption of debris along this plane, which could in turn account for the pattern of mass extinctions on Earth.

In 1984, paleontologists David Raup and Jack Sepkoski found a pattern of mass extinctions in the fossil record dating back 250 million years.  They discovered that every 26 million years, a mass extinction occurred.  The lack of any Earth-based evidence of any sort of change led the team to believe that the cause was extra-terrestrial.  The existence of Tyche could explain this pattern due to the orbit of Tyche disrupting Oort Cloud objects and send them towards the inner Solar System, thereby increasing Earth’s chances of an impact like the one that is believed to have killed the dinosaurs.

NASA’s WISE Telescope (Wide-Field Infrared Survey Explorer) may have already discovered Tyche.  In April, the first batch of data from the telescope is set to be released.  Matese and Whitmire think that it will reveal the existence of Tyche within two years.  The object they are looking for is believed to have cloud bands much like Jupiter, and have a temperature of -73C, or five times warmer than Pluto.  The heat would be left over from its formation, and would take longer to cool off due to its size.

If Tyche is found to exist, though, it would not add to the number of planets in our Solar System, as it most likely formed around another star and then captured by the Sun’s gravitational field.  The International Astronomical Union would most likely create a new category for this planet.