# Why does our atmosphere appear spherical while Earth itself is clearly not (e.g., elevations from ocean trenches to mountains)?

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Why does our atmosphere appear spherical while Earth itself is clearly not (e.g., elevations from ocean trenches to mountains)?

In: Physics

I hope this qualifies as ELI5, but I’m assuming you mean that the earth appears to be quite rough, what with all the mountains and trenches and what not. Well, it has been proven that a billiard ball, when examined microscopically, to a scale that would be equal to the earth, the billiard ball is way more rough than the earth. Or look at it this way, if you were to grow a billiard ball to be the same size as the earth, it would have taller mountains and deeper valleys than the earth. Now, think how smooth a billiard ball is, the earth is actually smoother. That is way the atmosphere is spherical, cuz the earth is actually a pretty smooth ball.

The earth is 7,918 miles across. That makes Mt. Everest’s 5odd miles high a 0.07% maximum deviation in the sphere.

On our scale the Earth is jagged and rocky. On the Earth’s own scale, it’s almost perfectly smooth.

Thank you so much guys! Apparently Neil deGrasse Tyson covered this exact topic on a Joe Rogan podcast back in August with basically the same answers. You guys rock.

The Earth’s atmosphere is not strictly spherical, but it will more closely resemble the “oblate sphereoid” that is a more realistic ideal of a planet undergoing rotation.

If you toss a pebble into a pond does the pond now have a pebble-shaped water bump on top? No, of course not, the water flows down to fill all the gaps and finds a level on top. The same is true of air.