Top 10 Amazing Facts About Earth’s Gravity

Of all the things we know about our home planet, Earth, one of the most interesting yet least understood is gravity. It’s actually quite remarkable how much we’ve figured out about it through observation and experimentation.

But there are still several facts about Earth’s gravity that you may not know – some pretty amazing! Here are 10 amazing facts about Earth’s gravity, in no particular order…

Fact 1 – The pull of gravity is present everywhere

a fact proven by Newton’s Law of Universal Gravitation, which states that gravity is a force between two bodies that is directly proportional to their masses and inversely proportional to their distance apart. In other words, gravity is everywhere.

If you jump high in an attempt to get above it, you will actually be pulled back down by gravity even more strongly than if you hadn’t jumped at all!

Fact 2 – We are about 93 million miles from the sun

Light travels 300,000 km (186,000 miles) in a second; that means it takes light 8 minutes to travel from our sun to earth. Eight of these and you’ve got almost an hour—but because of earth’s gravity.

Light travels even slower: it’s actually closer to 9 hours for a photon to make its way from our star to us. The result? One sunset lasts about two weeks!

Fact 3 – Einstein proved that gravity was related to mass, not distance

Imagine two objects. One has twice as much mass as another, so it attracts objects with twice as much force (gravitational pull). Now take those two objects and put them exactly 1 AU apart from each other. The second object will still attract things with twice as much force because it’s still got twice as much mass.

But it’s now 1 AU away from whatever it’s attracting — far enough that Newton predicted its gravitational effect would be negligible.

Fact 4 – The moon doesn’t orbit the earth because of gravity, but rather its inertia

Because our planet is much larger than any other, it’s more naturally drawn toward its surface. The moon is able to maintain its relative distance from us because of its inertia, or natural resistance to movement.

While we don’t feel gravity on a small scale—when we jump off a ledge, for example—it does exist when forces are moving at enormous speeds and distances. In fact, that inertia is what allows space probes to orbit planets without colliding with them.

Fact 5 – Every other planet in our solar system revolves around the sun because of gravity

Mars revolves around it every 24 hours and 56 minutes; Venus does so every 224.7 days; Mercury orbits our sun once every 88 days.

However, there is no solid evidence that Mars, Venus or Mercury have any kind of natural satellites (moons) that revolve around them. Our planet has one big moon, which we call Luna or the Moon – it takes 27 days and 20 hours to orbit our planet.

Fact 6 – Water makes up 70% of an adult’s body weight

Water is vital to keeping us alive and healthy. In fact, it makes up 70% of an adult’s body weight. It helps maintain your temperature, transports nutrients around your body and flushes out toxins from cells and tissues. If you lost just 1% of your body weight in water it could be life-threatening – so don’t take it for granted!

Fact 7 – Earth has a molten core that spins

The fastest moving part of Earth is its molten core. This liquid at its center takes only about 20 minutes to complete one revolution. In contrast, it takes our planet 24 hours to rotate completely once on its axis.

If you could view our spinning earth from a distance, you would see that it spins in a counter-clockwise direction. This is true of all planets in our solar system.

Fact 8 – A bath tub will overflow if it is filled above 80% capacity and you turn on both faucets at full blast

The bathtub is a fun example to help you understand gravity. The reason water will continue to overflow is because of a process called Archimedes’ principle, which states that any object wholly or partially immersed in a fluid will be acted upon by an upward buoyant force equal to the weight of fluid displaced by that object.

For us humans, it means we will float because our bodies displace enough water to create an upward buoyant force equal to our weight.

Fact 9 – Birds and planes can fly using lift created by air currents caused by the pull of gravity

Lifting yourself up with your arms is a challenge, but birds do it all day long without even thinking about it. Airplanes are also able to fly using lift created by air currents caused by gravity.

These wind currents come from something called convection cells, which form when warm air rises, pushes aside cooler air and sinks back down again. This continual upward and downward movement of warm and cool air makes convection cells.

Fact 10 – Ships can float because water is less dense than wood. This allows them to displace more water than they weigh.

Lighter-than-water ships can float because water is less dense than wood. This allows them to displace more water than they weigh. In addition, a ship has a large surface area (larger than its volume), which allows it to displace more water in proportion to its weight than an equal-sized solid object would.

The most important factor governing how easily something floats is its relative density, or specific gravity (SG). Specific gravity compares a material’s density with that of water.

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