Terrestrial gravity. Force and law of gravitation

15/04/2026

The online gravity simulations on this page will help you understand what gravity is and in particular, terrestrial gravity, how the force of gravity acts on any object. We will also discover what the law of universal gravitation is and why it is so important.

This Thematic Unit is part of our Earth Sciences collection

Center of Gravity

Specific point where the resultant gravitational force of a body is considered to act.

Escape Velocity

Minimum speed for an object to escape the gravitational pull of a celestial body. Usually measured in kilometers per second (km/s).

Gravitational Acceleration

Intensity of the gravitational field on the surface. The SI unit of measurement is the meter per second squared (m/s2).

Gravitational Field

Area of space in which a mass exerts its attractive influence on others.

Gravity

Mutual force of attraction between bodies with mass.

Law of Universal Gravitation

Law stating that attraction between bodies depends on their masses and distance.

Mass

Amount of matter in a body, constant throughout the universe. The SI unit of measurement is the kilogram (kg) and in the English system the pound (lb).

Microgravity

Condition of apparent weightlessness experienced by objects in free fall or orbit.

Weight

Gravitational force acting on a mass and varies by location. The SI unit of measurement is the Newton (N) and in the technical system the kilopond (kp).

What is terrestrial gravity

Terrestrial gravity is the force of attraction that the Earth exerts on all objects that have mass, keeping them stuck to its surface. As a force, it is also known as the force of gravitation or the force of gravity. It is responsible for the fact that, when an object is dropped, it inevitably falls to the ground, as well as the seas, the atmosphere and even our own bodies remain attached to the planet. It is a very weak force compared to other fundamental forces, such as the electromagnetic force, but its range is infinite.

Law of universal gravitation

According to Newton’s law of universal gravitation, the gravitational force between two objects is directly proportional to the mass of each object and inversely proportional to the square of the distance between them. That is, the greater the mass of an object, the greater the gravitational force it exerts, and the greater the distance between two objects, the smaller the gravitational force acting between them.

Importance of gravity

The force of gravitation is responsible for keeping the planets in orbit around the sun and for keeping us glued to the surface of the Earth. Without gravity, the planets would move in straight lines instead of following elliptical orbits, and we would float in space instead of being attached to the surface of the Earth.

Understanding gravity is essential to our understanding of the large-scale universe. Gravity is crucial in the formation of galaxies and the structure of the universe as a whole. Understanding how gravity works helps us explain phenomena such as the formation of black holes, the interaction of stars and galaxies, and the expansion of the universe.

These online gravity simulations show us what gravity is and how it acts Come on!

Center of Gravity

Specific point where the resultant gravitational force of a body is considered to act.

Escape Velocity

Minimum speed for an object to escape the gravitational pull of a celestial body. Usually measured in kilometers per second (km/s).

Gravitational Acceleration

Intensity of the gravitational field on the surface. The SI unit of measurement is the meter per second squared (m/s2).

Gravitational Field

Area of space in which a mass exerts its attractive influence on others.

Gravity

Mutual force of attraction between bodies with mass.

Law of Universal Gravitation

Law stating that attraction between bodies depends on their masses and distance.

Mass

Amount of matter in a body, constant throughout the universe. The SI unit of measurement is the kilogram (kg) and in the English system the pound (lb).

Microgravity

Condition of apparent weightlessness experienced by objects in free fall or orbit.

Weight

Gravitational force acting on a mass and varies by location. The SI unit of measurement is the Newton (N) and in the technical system the kilopond (kp).

Explore the exciting STEM world with our free, online, simulations and accompanying companion courses! With them you’ll be able to experience and learn hands-on. Take this opportunity to immerse yourself in virtual experiences while advancing your education – awaken your scientific curiosity and discover all that the STEM world has to offer!

Gravity simulations

Lab I
Lab II
Planets

Gravitational Force Lab I

Visualize the gravitational force that two objects exert on each other. Discover the factors that affect gravitational attraction and determine how adjusting these factors will change the gravitational force.

Gravitational Force Lab II

Visualize the force of gravity that two objects exert on each other. Change the properties of the objects in order to see how changing the properties affects the gravitational attraction.

Planet lab

In the last of these online gravity simulations, we see how different factors affect the force of gravity on a person.

Law
Lab I
Lab II
Planets

Newton’s Law of Gravitation

The Law of Gravitation states that the force of gravity is proportional to the product of the masses and inversely proportional to the square of the distances.

Gravitational Force Lab I

Gravitational Force Lab II

Visualize the force of gravity that two objects exert on each other. Change the properties of the objects in order to see how changing the properties affects the gravitational attraction.

Planet lab

In the last of these online gravity simulations, we see how different factors affect the force of gravity on a person.

Giants of science

“If I have seen further, it is by standing on the shoulders of giants”

Isaac Newton

Léon Foucault

1819

–

1868

Léon Foucault demonstrated Earth’s rotation with his famous pendulum and measured the speed of light with great precision, revolutionizing experimental optics

“The pendulum does not lie: the Earth moves beneath our feet”

Johannes Kepler

1571

–

1630

Kepler formulated the three laws of planetary motion, establishing elliptical orbits and the relationship between planetary period and distance from the Sun

“The heavens teach the geometry that nature follows”

Become a giant

Your path to becoming a giant of knowledge begins with these top free courses

Free mode

The Radio Sky II: Observational Radio Astronomy

Free mode

The Radio Sky I: Science and Observations

Free mode

Our Place in the Universe

Free mode

Sensing Planet Earth – Water and Ice

Free mode

Introduction to Deep Earth Science

Free mode

Sensing Planet Earth – From Core to Outer Space

Free mode

The History of Ancient Environments, Climate, and Life

Professional development for Educators

Your path to becoming a giant of knowledge begins with these top free courses

Free mode

Teach kids computing: Programming

Free mode

Teach teens computing: Developing your programming pedagogy

Free mode

Teaching with Physical Computing: Soft skills, teamwork and the wider curriculum

Free mode

An Introduction to Evidence-Based Undergraduate STEM Teaching

Giants of science

“If I have seen further, it is by standing on the shoulders of giants”

Isaac Newton

Nicolaus Copernicus

1473

–

1543

Nicolaus Copernicus revolutionized astronomy by placing the Sun at the center of the planetary system; he provided precise mathematical observations.

“The Sun, not the Earth, is the center of our planetary system”

Johannes Kepler

1571

–

1630

Kepler formulated the three laws of planetary motion, establishing elliptical orbits and the relationship between planetary period and distance from the Sun

“The heavens teach the geometry that nature follows”

Become a giant

Your path to becoming a giant of knowledge begins with these top free courses

Free mode

The Radio Sky II: Observational Radio Astronomy

Free mode

The Radio Sky I: Science and Observations

Free mode

Our Place in the Universe

Free mode

Sensing Planet Earth – Water and Ice

Free mode

The History of Ancient Environments, Climate, and Life

Free mode

Our Global Ocean – An Introduction Course

Free mode

Introduction to Deep Earth Science

Professional development for Educators

Your path to becoming a giant of knowledge begins with these top free courses

Free mode

Teach computing: Moving from Scratch to Python

Free mode

HP AI Teacher Academy

Free mode

Teach teens computing: Cybersecurity

Free mode

Higher education teaching in the age of AI

Test your knowledge

What role does gravity play as a fundamental force in shaping the structure and stability of physical systems?

Gravity acts as a universal force that influences every object with mass, from tiny particles to massive celestial bodies. Its long‑range effect and cumulative nature make it essential for the formation and stability of large‑scale structures. Gravity keeps planets in orbit around stars, binds stars together within galaxies, and holds atmospheres around planets. Even though it is the weakest of the fundamental forces, its influence dominates at large distances and large masses. Without gravity, matter would not clump together, planets and stars would not form, and the universe would be a scattered collection of particles with no organized structures. Its presence is therefore crucial for the existence of stable systems and for the conditions that allow life to emerge.

How is the gravitational interaction between objects related to their mass, and what consequences does this relationship have for their motion?

The strength of the gravitational attraction between two objects increases with their mass. A more massive object exerts a stronger pull, which explains why Earth’s gravity is far more noticeable than that of smaller objects around us. This relationship governs how bodies move: Earth’s gravity causes objects to fall toward its surface, while the Sun’s gravity keeps planets in stable orbits. The connection between mass and gravitational influence also explains why massive bodies shape their surroundings, affecting trajectories, orbital paths, and the behavior of nearby objects. Understanding this relationship is key to explaining phenomena such as weight, free fall, and the dynamics of planetary systems.

If gravity is always pulling us down, why don’t we feel like we’re being “pressed” all the time?

Because our bodies are completely adapted to living under Earth’s gravity. Our muscles, bones, and sense of balance have developed to handle this constant pull without us noticing it. We only feel something unusual when gravity changes—like in an elevator that suddenly accelerates or on a roller coaster. Under normal conditions, gravity feels so familiar that it becomes invisible to us.

Why do objects fall at the same rate even if one is heavy and the other is light?

Because gravity accelerates all objects equally, regardless of their mass. What makes some objects fall slower in everyday life is air resistance, not weight. If you remove the air—like in a vacuum chamber—a feather and a hammer fall exactly the same way. Mass affects the gravitational force, but it also affects inertia, and those two effects cancel out perfectly.

What would happen if Earth’s gravity were a bit stronger or a bit weaker?

If gravity were stronger, everything would feel heavier. Moving around would require more effort, jumping would be nearly impossible, and many animals might not be able to support their own weight. If gravity were weaker, we’d feel lighter and movement would be easier, but the atmosphere would be thinner and objects could escape into space more easily. Earth’s current gravity is a delicate balance that makes our environment stable and suitable for life as we know it.