Its discovery began with Sedna.

Sedna is a dwarf planet smaller than Pluto.

Scientists believe Sedna is in the gravitational pull of a large object, which could be this new planet — aka "Planet 9." (Video via Kurdistan Planetarium)

It has about 10 times the mass of Earth.

It's an average of 600 times farther from the sun than the Earth is and takes 20,000 years to orbit the sun once.

This video includes images from NASA.

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Amy Stevens, a U.S. Navy veteran who founded Georgia Military Women, was inducted this month into the Georgia Military Veterans Hall of Fame. She recently visited the Atlanta History Center's exhibit, “Our War Too: Women in Service." (Arvin Temkar/AJC)

Credit: arvin.temkar@ajc.com

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Fulton County Sheriff Patrick Labat gives a tour of Fulton County Jail in  2023. (Natrice Miller/AJC 2023)

Credit: Natrice Miller/AJC