Som ET - 35 - Universe - Pluto

Pluto’s classification as a planet has had a history of changes. Since 2006, per the International Astronomical Union’s planetary criteria, Pluto isn’t considered a planet because it hasn’t cleared the neighborhood around its orbit of other objects. However, it does meet IAU’s criteria for what constitutes a dwarf planet.

Pluto – which is smaller than Earth’s Moon – has a heart-shaped glacier that’s the size of Texas and Oklahoma. This fascinating world has blue skies, spinning moons, mountains as high as the Rockies, and it snows – but the snow is red.

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Credit: NASA/APL/JHUAPL/SwRI & ESA