Children may need to count nine planets in the solar system again.

Pluto, once considered the farthermost planet, was ousted in 2006 from the ranks of the major planets by the International Astronomical Union. It was then classified as a "dwarf planet." But recently, a debate at the Harvard-Smithsonian Center for Astrophysicists (HSCFA) led to a majority decision that the outcast body can finally pave its way back to the solar system's Big League.

The debate took place among three astronomy experts, concentrating on the central question "What is a Planet?" As reported by the Sydney Morning Herald, the International Astronomical Union imposed that a planet has to meet the following standards:

1. It must be in orbit around the Sun.

2. It must have sufficient mass to assume hydrostatic equilibrium (a nearly round shape).

3. It must have "cleared the neighbourhood" around its orbit, meaning it has its orbit all to itself.

These are the criteria which Pluto may not have satisfied when it was relegated eight years ago.

The HSCFA built on the premise that the definition of a planet has "baffled the public and classrooms around the country." The three debating experts thus focused on this concept.

The Center probed on the definition, saying:

"For one thing, it only applied to planets in our solar system. What about all those exoplanets orbiting other stars? Are they planets? And Pluto was booted from the planet club and called a dwarf planet. Is a dwarf planet a small planet? Not according to the IAU."

Inquisitr reported that the decision to give back Pluto its planetary status was a congregational choice.

The Irish Examiner listed the debaters' arguments:

1. Historian Owen Gingerich argued: A planet is a culturally-defined word that changes over time. Pluto IS a planet.

2. IAU's Gareth Williams argued: A planet is a spherical body that orbits the sun and has cleared its path. Pluto IS NOT a planet.

3. Harvard's Dimitar Sasselov argued: A planet is the smallest spherical lump of matter that formed around stars or stellar remnants. Pluto IS a planet.

Sasselov's point proved to be the most convincing for the audience.

Meanwhile, NASA reported the circumstances that led to Pluto's prior rejection. The space agency wrote, "In 2003, an astronomer saw a new object beyond Pluto. The astronomer thought he had found a new planet. The object he saw was larger than Pluto. He named the object 'Eris.'"

The discovery of Eris led to astronomers scratching their heads about what makes a planet a "planet."

See why IAU ousted Pluto back in 2006 here.

Does Pluto deserve to be a planet? Let us know.

Watch the debate in full swing below.