How far is the average horizon on all the planets?

The distance to a horizon—in a hypothetically smooth surface—is given by this equation: [math]d= \sqrt{ \left( 2Rh \right) } \tag*{}[/math] Where [math]h[/math] is the height of said human, and [math]R[/math] is the radius of the planet. read more

Average: 4.50 billion km / 2.8 billion miles (30.1 AU) Closest to Neptune from Earth: 4.3 billion km / 2.7 billion miles As a special bonus, we’ll include Pluto too, even though Pluto is not a planet anymore. read more

The top row of planets shows the distance in kilometers or miles. The second row of planets dotted on a line illustrates their relative distance from the Sun and each other. Distance from the Earth. The planets' distance from the Earth varies because all the planets orbit the Sun on different elliptical paths. read more