What Is Gravity, and How Does It Work?
As Wile E. Coyote has learned many times, gravity will pull objects back down to Earth, no matter what they do to try and escape
By definition, Gravity is the attraction shared between two (or more) objects that each have mass. The more mass an object has, the stronger its force of gravity is.
The Earth’s gravity pulls you towards the planet, and keeps you from floating away into space. Your body actually has its own gravitational pull, but you are much smaller than the Earth, so its own force beats out yours.
Gravity is also what pulls the baseball you throw back to the ground, and what pulls you back to the ground when you jump. Without gravity, the baseball would fly in a straight line until it hit something, and you would fly into space forever if you jumped.
Gravity also works on a much larger scale, with planets, stars, galaxies, and the universe in general. The gravitational pull of planets is what causes asteroids and meteors to crash into their surfaces. Gravity is also responsible for planets orbiting their respective stars, and for moons orbiting their respective planets.
Different planets have different gravitational strengths, depending on their mass. Larger, or more massive, planets, like Jupiter or Saturn, have gravitational pulls that are much stronger than the Earth’s, while smaller, or less massive planets like Mercury or Mars, have gravitational pulls that are much weaker than the Earth’s.
- It’s worth noting that the visual size of a planet isn’t what gravity is based on – the force is determined by the mass, meaning what makes up the planet. For instance, Saturn is a gas planet with much less mass for its size, while the Earth is a solid planet, with much more mass for its size. Despite this, Saturn is still much more massive than the Earth, and its size makes up for it being gaseous.
- A great example of mass versus size is comparing Earth and Uranus. Uranus is close to five times the size of Earth (radius), but it still has a weaker gravitational force than the smaller planet. Uranus is a gas planet, while the Earth is a terrestrial planet, meaning the Earth has more mass than Uranus, leading it to have a stronger force of gravity.
Despite how strong gravity is, we’ve actually found a way to beat it. To get to space and to the moon, rocket ships have to be able to make it out of the range of the Earth’s gravitational pull, and to do that they need a lot of power and speed. Rocket ships consume over 10,000 pounds of fuel a second to escape gravity, and even then, rockets are still majorly affected. Instead of flying straight up into space, rockets follow the curvature of the earth – similar to how an experienced swimmer may swim perpendicular to a current to avoid fighting the force and conserve energy – and curve around the Earth before exiting the planet’s gravitational range.