Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
The circumference of Earth at the equator is about 24,902 miles (40,075 km), but from pole-to-pole â the meridional circumference â Earth is only 24,860 miles (40,008 km) around. This shape, caused by the flattening at the poles, is called an oblate spheroid.
Letâs take a look at how big our planet is. Blue marble Earth. Image credit: NASA. First, the equatorial diameter of Earth is 12,756 km. In other words, if you dug a tunnel on the equator that went straight down and went right through the center of the Earth, it would be about 12,756 km long.Just for comparison, thatâs about 1.9 times the diameter of Mars.lue marble Earth. Image credit: NASA. First, the equatorial diameter of Earth is 12,756 km. In other words, if you dug a tunnel on the equator that went straight down and went right through the center of the Earth, it would be about 12,756 km long.