It’s always exciting when new scientific discoveries are announced. It’s even exciting to talk about scientific discoveries that aren't yet confirmed. Such is the case for the potential ninth planet that astronomers have been theorizing about based on observations of the solar system.
Astronomy contributor Jean Creighton explains that the solar system has one star, the sun; eight planets and "leftovers" of various kinds such as asteroids, comets and more than 1,000 Kuiper Belt objects. These KBOs exist past the orbit of Neptune and, she says, are "icy worlds that were left over from when the solar system formed."
Astronomers have been making observations in the last few years that some of the Kuiper Belt objects seem to have "strange orbits." Creighton says that about 6-10 of the objects are all pointing in the same direction.
According to Creighton, this is interesting because, "you would think that over time these things would relax, and over time they would move into some random direction, not all strategically pointed in the same place." Astronomers have also noticed that they all have the same inclination with respect to the main plane in the solar system, making it even less likely to be a coincidence.
So scientists have been looking into the explanation that the Kuiper Belt objects are situated due to the gravitational pull of a planet - a very exciting theory that could add another planet to our solar system.
"It could be about 10 times the mass of the earth, 5,000 times bigger than Pluto, 2-4 times bigger than the earth in terms of its radius and the distance would be 20 times further than Neptune," Creighton describes. "It would take over 10,000 years for this planet to go around the sun once."