This video explains how the number of planets in our solar system depends on how we define a “planet.” The International ...

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Explore the wonders of the universe in this video as we delve into the question: How many planets exist in the universe? Gain ...

It was almost 100 years ago that Clyde W. Tombaugh discovered Pluto. That was the last planet found until 1992, when humans found another one. But this new planet wasn't in our solar system—it was ...