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We used to say Pluto. Is Pluto a planet? Does it qualify? For an object to be a planet, it needs to meet these three requirements defined by scientists:
It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet.
It needs to have enough gravity to pull itself into a spherical shape – Pluto…check
It needs to have "cleared the neighborhood" of its orbit – Uh oh. Here's the rule breaker. According to this, Pluto is not a planet. It's in a belt of 70,000 objects, some with the same composition and even larger.
So the answer is Neptune
What is the farthest planet from the sun?