Way out beyond Mars, but before you get to Jupiter, is a planet.

You read that right. There's a planet between Mars and Jupiter.

You may not have heard of it, but it was discovered in 1801 -- 129 years before Pluto. It originally was called a planet, then later an asteroid and now it's called a dwarf planet.

Its name is Ceres (pronounced like series) and you'll likely be hearing a lot more about it in the coming weeks.

Ceres is one of five named dwarf planets recognized by NASA and the International Astronomical Union (IAU). The other four are Eris, Pluto, Makemake and Haumea.

But Ceres is the first of these worlds to get a visitor from Earth: NASA's Dawn spacecraft is arriving on March 6.

"Ceres is a 'planet' that you've probably never heard of," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

Ceres may be considered a dwarf planet, but it's "the giant of the main asteroid belt," Dr. Marc Rayman, chief engineer and mission director of the Dawn mission, told CNN. "It is not only the largest object between Mars and Jupiter, it is the largest object between the sun and Pluto that a spacecraft has not yet visited."

"We are tremendously excited," Rayman said. "We have guided this robotic probe for well over seven years on an interplanetary journey of more than 3 billion miles. Along the way we sailed past Mars. We spent 14 months orbiting and scrutinizing the giant protoplanet Vesta. ... Now, finally, we are on the verge of conducting the first exploration ever of the first dwarf planet."

New images from Dawn, taken when the probe was about 52,000 miles (83,000 kilometers) from Ceres, show craters and what NASA calls mysterious bright spots. Rayman said its surface is pretty beaten up and that the craters that are "scars from life in the rough and tumble asteroid belt."

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NASA spacecraft to reach dwarf planet soon