Gravity falls with height at the Earth's surface (sea level), therefore linear extrapolation would result in zero gravity at a height of one-half of the Earth's radius (9.8 m*s-2 per **3,200 km**.) and altitude h in metres. This would occur at an angle of **about 22.5 degrees** above the horizon.

However, due to air resistance, actual drops in gravity are observed about three-fourths of the way to the moon. At that distance, the downward force of gravity is equal to about 1/150th of its value at sea level. Therefore, if you were standing on the edge of this crater, you could jump out and keep going forever!

The average depth of **this crater** is about 6 miles (10 km). It was formed by **a meteorite impact** approximately 65 million years ago. The energy released by the impact was enough to create **a new island** larger than France, Switzerland, and Germany combined. The rock ejected from the crater settled back into it again soon after formation causing the crater to grow over time.

There are actually several different zones within the Moon. The far side faces away from Earth so any objects on it that move across the face are invisible until they come into view.

Because there is no atmosphere to resist movement, all objects in space travel at very high speeds.

As a result, at a height of h = 0005RE, the acceleration due to gravity is reduced by 1%. Because the planet is somewhat flattened at the poles, the radius of the earth differs at the equator and at the poles. At the equator, the radius is r = 0507313km; at **the North Pole**, it's r = 0505840km. The density of the earth is generally believed to be about 30000kg/m3, which means that there are about **3×1030 atoms** in **each cubic meter** of earth (note: this is only about 2% less than the number of particles in the universe).

If we assume a spherical earth, then the weight of the earth is proportional to its radius squared. So if the radius increases by 1%, then the weight increases by 3%. This means that if you were to climb into the sky and keep climbing, you would eventually reach zero gravity! The reason we don't all do this is because the air resistance would be too great to overcome.

However, if the entire earth was covered by water, then the weight on any given point would be equal to the weight of the water above it. If we assume a depth of 1000 meters for the ocean, then the pressure would be about 100 N/cm2.

On Earth, it is 9.8 m/s2. That means, the acceleration of gravity at **sea level** on the Earth's surface is 9.8 m/s2. The value of g varies slightly near the earth's surface. These differences are caused by the varied density of the geologic formations underneath each given surface location. Denser materials will cause g to be less than 9.8 m/s2 at **that location**.

Below sea level, the effect of gravity on objects becomes very small because there is so much water between them and the ground that they do not feel any force from gravity. At a depth of **100 meters** (330 feet), only 1% of the normal gravity field exists.

The gravity field decreases in magnitude as you go deeper undersea. At a depth of 3000 meters (10500 feet), only 0.5% of the normal gravity field exists.

This is why astronauts experience zero gravity during space flights. They are floating through space with no connection to the planet below them.

Gravity decreases as you go deeper because there is less mass above you compared to the volume of space you're moving through. As soon as your distance exceeds **10,000 kilometers** (6,214 miles), Earth's gravitational pull on you becomes too weak to keep you afloat. You would need **enough material** to fill up your pressure vessel so that its weight is greater than the pressure pushing it down toward the planet's surface.