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How big around is the Earth? ∞

From pole to pole, the Earth [ 1 ] is about 40,008 kilometres (km) around. The Earth is round, but think of it like a ball that bulges in the middle. The Earth is a bit wider than it is tall, at about 40,075 km around the equator. (reference, See the infobox.)

We ignored that the surface around the equator is mostly Ocean (over 71% of the Earth’s surface is water), and that the Earth is not a smooth surface, with both mountains and valleys on land and in the ocean.

• The tallest mountain is Mount Everest is 8,848 meters above sea level.

• The deepest ocean valley is the Mariana Trench, at 10,924 meters below sea level.

“Sea level” is an interesting idea, since the oceans aren’t even at equilibrium. The geoid is an idealized surface that equals all the sea water out into one even-height surface.

Walking a kilometer ∞

An average walking speed is about 4 to 5 km/h. (reference)

How many minutes would it take us to walk one kilometer? Well, at 5 km/h it would only take us 1/5 of an hour, or 1/5 of 60 minutes. That’s 60/5 or just 12 minutes.

Remember that walking speed depends heavily on factors such as height, weight, age, terrain, surface, load, culture, fitness and rest stops.

Walking around the equator ∞

If the Earth’s circumference is 40,075 km and we walk at 5 km/h..

Then it would take us 8,015 hours to walk. (40075/5)

That’s about 334 days (8015/24) non-stop. Remember to stretch first!

Driving around the equator ∞

A vehicle would move a lot faster than a walking person. Let’s pretend we have an electric hovercar which travels at 100 km/h.

How much faster is our hovercar than just walking? 5 km/h walking vs 100km/h driving is 20 times faster. (100/5)

So in our car it would take us about 2,004 hours (40075/20) or about 84 days (40075/20/60) to drive the whole 40,075 km circumference of the Earth non-stop.

That’s better than walking, and this time we don’t have to worry about being rained on.

Continues with Our Solar System.

Footnotes

1. When referring to the planet, it’s capitalized “Earth”. [ ↩ ]