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 the force by which a planet or other body draws objects toward its center. Defines words in "Sign Here" game. How Do We Launch Things Into Space? You need a rocket with enough fuel to escape Earth's gravity!
What is gravity space place? ›
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.
What is gravity in space 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 gravity according to 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 space NASA for kids? ›
NASA stands for National Aeronautics and Space Administration. NASA was started on October 1, 1958, as a part of the United States government. NASA is in charge of U.S. science and technology that has to do with airplanes or space.
How does gravity space work? ›
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 an example of gravity in space? ›
Gravity keeps the International Space Station in orbit around the Earth. Gravity keeps the Moon orbiting around the Earth. Gravity keeps the Earth orbiting around the Sun.
What is an example of gravity for kids? ›
We can throw something like an egg up into the air, but no matter how high you throw the egg, gravity will slow it down and then pull it back down to the ground. The force of gravity brings things down no matter what direction you throw it.
Is gravity real or is it space time? ›
However, in the broader sense, gravity is indeed a force because it describes the resulting interaction between two masses. Gravitational effects are fundamentally caused by the warping of spacetime and the motion of objects through the warped spacetime. However, the end result is as if a force was applied.
Is gravity and space the same thing? ›
No, but they are often confused, especially when people describe gravity as the “warping of spacetime” or speak of the “expansion of space” in the context of cosmology.
NASA provides a safe place for children to play 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 is space facts for kids? ›
The Sun is so big that the Earth could fit inside it 1.3 million times over. There are more stars in space than there are grains of sand in the world. The footprints made by the Apollo 11 astronauts will probably stay there for at least 100 million years.
Does NASA still exist? ›
NASA Today
At its 20 centers and facilities across the country – and the only National Laboratory in space – NASA studies Earth, including its climate, our Sun, and our solar system and beyond. We conduct research, testing, and development to advance aeronautics, including electric propulsion and supersonic flight.
Where is the center of gravity in space? ›
Gravity itself does not have a specific location; it is present everywhere. Therefore, there is no such thing as an absolute "Center of Gravity" for the universe, just as there is no such thing as the center of the surface of a sphere.
Is there a gravity room on Earth? ›
NASA Glenn's Zero Gravity Research Facility houses a 432-foot drop tower, built into the ground, which provides test articles a near-weightless environment for 5.18 seconds, and makes this the world's largest drop tower of its kind.
Are there places in space with no gravity? ›
There is no such thing as zero gravity in space. Gravity is everywhere in the universe and manifests itself in black holes, celestial orbits, ocean tides, and even our own weight.
What is the place where gravity is opposite? ›
A gravity hill, also known as a magnetic hill, mystery hill, mystery spot, gravity road, or anti-gravity hill, is a place where the layout of the surrounding land produces an optical illusion, making a slight downhill slope appear to be an uphill slope.
