Scientists may have discovered the solar system’s most distant object, more than three times farther away from the Earth than Pluto.

The object, about 8 billion kilometers from Earth, has been given the provisional name of Sedna, after the Inuit goddess who created sea creatures of the Arctic.

The finding has sparked debate over what constitutes a planet.

“After the discovery of the ninth planet, it didn’t occur to scientists that there might be more objects of the same size out there,” NIU Physics Professor Sue Willis said.

There are several traits that scientists consider to be characteristic of planets.

Observatory Manager Andrew Morrison said the object has to be orbiting the sun, should be large enough that its own gravitational field will make it spherical in shape and should be big enough to have its own moon or support its own satellites.

Mike Brown of the California Institute of Technology and a team of astronomers found Sedna in November as part of an ongoing three-year outer solar system project.

The nine planets in the solar system have been found in various ways.

The first five planets were found predating telescopes because they are visible to the naked eye, Willis said.

Based on the understanding of Johannes Kepler’s laws of planetary motion, scientists realized there must be another planet, and by scanning the sky and taking measurements, scientists predicted where Neptune would be, Morrison said.

“It’s unique how all of them were discovered,” he said.

The names of planets typically follow the tradition of Roman mythology, Willis said, and an astronomical naming agency makes the names official.

Not only scientists with credentials can discover a planet, Morrison said.

Traditionally, people will take pictures of the sky and, over a period of time, will look for things that are moving, Willis said.

“It doesn’t take the biggest telescope to do important astronomical work,” Morrison said. “You just have to have a lot of patience.”