What are the Earth's circumference and mass?

Alright, this is an interesting question. Let's talk about Earth's "measurements" and "weight."

Question Title: What are the Earth's circumference and weight?

Question Tags: Earth, Science Popularization, Geography

Hello! Here's an easy-to-understand explanation regarding Earth's circumference and weight.

I. Earth's Circumference: It's Not a Perfect Sphere

You might think Earth is a perfect sphere, but it's actually more like an orange that someone a bit on the plump side sat on – slightly bulging at the equator and flattened at the poles. Therefore, its circumference has two main measurements.

Equatorial Circumference: Approximately 40,075 kilometers This can be thought of as Earth's "waistline," its longest circuit. If you could drive along the equator at, say, 120 km/h without stopping, it would still take you almost two weeks to complete one full lap.
Polar Circumference (Meridional Circumference): Approximately 40,008 kilometers This is the length from the North Pole to the South Pole and back to the North Pole on the other side of the Earth. Because it's slightly flattened at the poles, this circumference is a tiny bit shorter than the equatorial "waistline," by about 67 kilometers.

So, for simplicity, you can remember that "Earth's circumference is roughly 40,000 kilometers."

Here's a fun fact: The early definition of the unit "meter" was related to Earth's circumference. 1 meter was originally defined as "one ten-millionth of the distance from the North Pole to the Equator." So, the distance from the North Pole to the Equator is roughly 10,000 kilometers, and thus one full circuit (polar circumference) naturally became 40,000 kilometers.

II. Earth's "Weight": What We Actually Mean is Mass

This is a very common misconception. Strictly speaking, "weight" is the force of gravity acting on an object. Earth is essentially in a state of weightlessness in space (just like astronauts in a space station), so discussing its "weight" doesn't really make sense.

What we actually want to know is Earth's mass – that is, how much matter it contains.

Earth's mass is an unimaginably huge number:

Approximately 5.972 × 10²⁴ kilograms

Just looking at that number makes your head spin, right? Let's put it another way:

Roughly 60 sextillion metric tons. (That's 6 followed by 21 zeros, written as 6,000,000,000,000,000,000,000 metric tons)

It's precisely because Earth has such an enormous mass that it can generate a powerful enough gravitational pull to firmly attract the Moon, artificial satellites, and every one of us to its vicinity.

To summarize:

Circumference: Around the equator, approximately 40,075 kilometers.
Mass (what we commonly refer to as weight): Approximately 60 sextillion metric tons.

Hope this explanation helps you!