Can Pluto be brought back to an official planetary status once again?

In 2006, Pluto was demoted to a dwarf planet, which excluded it from the solar system's official neighborhood. Caltech researcher Mike Brown, the same scientist who detected another Earth-like exoplanet beyond Neptune, facilitated this demotion.

Now, NASA has released a new manifesto that proposes an entirely different way of defining planets. If this proposal holds true, more than 100 new planets will be added to the solar system, possibly adding the moon and Pluto.

Make Pluto A Planet Again

What does it take to consider a cosmic body a planet? By definition, which is taken from the International Astronomical Union, a planet is celestial body that orbits around the sun, has a nearly round shape, and has cleared the neighborhood around its orbit.

All of that may soon change. A team of NASA researchers led by Alan Stern, principal investigator of the New Horizons' Pluto mission, plans to redefine what a planet is in very simple terms.

For them, planets are "round objects in space that are smaller than stars." If this definition gets accepted by the IAU, it means that even the moon can potentially be classified a planet.

The key point that Stern and his colleagues hope to get approved is that cosmic objects in the solar system no longer need to be orbiting around the sun to be classified a planet.

The researchers say scientists should be considering the object's intrinsic physical properties, not its interaction with stars, which they believe holds more merit. They also argue that the current definition of planets is "inherently flawed."

For instance, the definition only classifies cosmic objects that orbit around the sun as planets, excluding those orbiting other stars or those orbiting freely as "rogue planets."

Second, the current definition requires zone-clearing, a criterion that no planet in the solar system satisfies. Stern and his colleagues explained that small cosmic objects constantly fly through planetary orbits.

Lastly, the researchers argue that the zone-clearing means calculations used to confirm if a cosmic object is a planet must be dependent on distance because a neighborhood around its orbit must be cleared out.

"Even an Earth-sized object in the Kuiper Belt would not clear its zone," the authors said.

New Horizons Flyby

In 2015, Stern spoke to Business Insider and said astronomers should not be the ones deciding what can be classified as planets. He said planetary scientists should have the authority over this jurisdiction, because they know more about the subject.

That same year, Stern and his team received incredible data from the New Horizons Pluto flyby.

"When we look at an object like Pluto, we don't know what else to call it," he added.

The team's full proposal can be read online. It has been submitted to the IAU for consideration.