Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun.
What else does gravity do?
Why do you land on the ground when you jump up instead of floating off into space? Why do things fall down when you throw them or drop them? The answer is gravity: an invisible force that pulls objects toward each other. Earth's gravity is what keeps you on the ground and what makes things fall.
An animation of gravity at work. Albert Einstein described gravity as a curve in space that wraps around an object—such as a star or a planet. If another object is nearby, it is pulled into the curve. Image credit: NASA
Anything that has mass also has gravity. Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is.
Earth's gravity comes from all its mass. All its mass makes a combined gravitational pull on all the mass in your body. That's what gives you weight. And if you were on a planet with less mass than Earth, you would weigh less than you do here.
Image credit: NASA
You exert the same gravitational force on Earth that it does on you. But because Earth is so much more massive than you, your force doesn’t really have an effect on our planet.
Gravity in our universe
Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. The gravitational pull of the moon pulls the seas towards it, causing the ocean tides. Gravity creates stars and planets by pulling together the material from which they are made.
Gravity not only pulls on mass but also on light. Albert Einstein discovered this principle. If you shine a flashlight upwards, the light will grow imperceptibly redder as gravity pulls it. You can't see the change with your eyes, but scientists can measure it.
Black holes pack so much mass into such a small volume that their gravity is strong enough to keep anything, even light, from escaping.
Gravity on Earth
Gravity is very important to us. We could not live on Earth without it. The sun's gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun's light and warmth. It holds down our atmosphere and the air we need to breathe. Gravity is what holds our world together.
However, gravity isn’t the same everywhere on Earth. Gravity is slightly stronger over places with more mass underground than over places with less mass. NASA uses two spacecraft to measure these variations in Earth’s gravity. These spacecraft are part of the Gravity Recovery and Climate Experiment (GRACE) mission.
The GRACE mission helps scientists to create maps of gravity variations on Earth. Areas in blue have slightly weaker gravity and areas in red have slightly stronger gravity. Image credit: NASA/University of Texas Center for Space Research
GRACE detects tiny changes in gravity over time. These changes have revealed important details about our planet. For example, GRACE monitors changes in sea level and can detect changes in Earth’s crust brought on by earthquakes.
article last updated December 17, 2020
FAQs
Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. The gravitational pull of the moon pulls the seas towards it, causing the ocean tides. Gravity creates stars and planets by pulling together the material from which they are made.
What is gravity in space facts for kids? ›
Gravity is a pulling force that works across space. That is, objects do not have to touch each other for the force of gravity to affect them. For example, the Sun, which is millions of miles from Earth, pulls on Earth and the other planets and objects in the solar system.
What is a gravity in space? ›
Every object in space exerts a gravitational pull on every other, and so gravity influences the paths taken by everything traveling through space. It is the glue that holds together entire galaxies. It keeps planets in orbit. It makes it possible to use human-made satellites and to go to and return from the Moon.
What is NASA's space place? ›
NASA Space Place is the fun place to learn about the solar system and the universe with games, crafts, stories and animations. Go to Website.
Is NASA kid friendly? ›
Info for Parents, Teachers, and Caregivers
NASA provides a safe place for children to play games as they learn about NASA and its missions. NASA encourages you to visit NASA Kids' Club and use its games and activities to inspire the next generation.
What are 3 facts about gravity? ›
Basic Facts About Gravity
- Gravity is a force of attraction that exists between any two objects. ...
- Projectiles, satellites, planets, galaxies, and clusters of galaxies are all influenced by Gravity.
- Gravity is the weakest of the four known forces of nature, yet the most dominant force.
General relativity tells us that what we call space is just another feature of the gravitational field of the universe, so space and space-time can and do not exist apart from the matter and energy that creates the gravitational field.
How does gravity work in NASA? ›
Gravity is an attractive force that all objects have for one another. The amount of the gravitational force between two objects is directly proportional to the product of their two masses and inversely proportional to the square of the distance between their centers of mass. The force of gravity is not constant.
What is gravity in science grade 6? ›
Gravity is the force of attraction between two objects. It is what makes things fall and what keeps us from floating off into space. Gravity is a fundamental force of nature.
Do we feel gravity in space? ›
In space, astronauts and their spaceship still have mass and are still acted upon by Earth's gravity. In this sense, they still have weight, even though Earth's gravitational force is smaller in orbit than it is on Earth's surface (Box 1). However, they do not feel their weight because nothing is pushing back on them.
Here are some amazing space facts to share with your aspiring astronauts and astronomers.
- Space is hugely, staggeringly big. ...
- Humans are sooooo slow. ...
- Some things you see in the sky aren't there anymore. ...
- Earth has already been invaded by Mars.
The NASA Kids Club caters to children in the age range of pre-K through grade 4 (between 6 to 12 years old). It offers a variety of games and activities that align with national education standards in STEM.
Where is space for kids? ›
It begins at a point known as the Kármán Line (100km from Earth) and extends beyond it. Space is also scientifically known as the Universe. The universe contains Galaxies and these galaxies have solar systems, stars, planets, etc within them. Earth is a planet in a galaxy called The Milky Way.
What is the NASA theory of gravity? ›
Gravity is an attractive force that all objects have for one another. The amount of the gravitational force between two objects is directly proportional to the product of their two masses and inversely proportional to the square of the distance between their centers of mass.
What is gravity spacetime? ›
Gravity as Curved Spacetime
Gravity feels strongest where spacetime is most curved, and it vanishes where spacetime is flat. This is the core of Einstein's theory of general relativity, which is often summed up in words as follows: "matter tells spacetime how to curve, and curved spacetime tells matter how to move".
Can NASA create gravity in space? ›
The only known way to create artificial gravity it to supply a force on an astronaut that produces the same acceleration as on the surface of earth: 9.8 meters/sec2 or 32 feet/sec2. This can be done with bungee chords, body restraints or by spinning the spacecraft fast enough to create enough centrifugal acceleration.
