Orbits. Orbital motion and types of orbits

09/04/2026

The online orbit simulations on this page will help us to know in more detail how are the orbital motion, the orbital trajectories and some of the main types of orbits.

What are orbits

Orbits are the trajectories (that is why the term orbital trajectory is also used) followed by objects in space as they move around another object due to the influence of gravity. In the context of the solar system, planets, asteroids and comets orbit the sun, while satellites orbit the planets. Understanding orbits is fundamental to astronomy and space exploration.

Orbital motion

We call orbital motion the continuous displacement of an object in space around another more massive object, guided by the influence of gravity. This motion is the result of a delicate balance between the gravitational force that pulls the object toward the central body and the tangential velocity of the object, which tends to push it away. This balance generates orbital trajectories that can vary in shape from perfect circles to ellipses and open trajectories such as parabolas and hyperbolas. It is a dynamic phenomenon observed in natural planets and satellites, asteroids and spacecraft, all following Kepler’s laws, which describe the relationship between the shape, velocity and position of the object in its orbit.

In addition to the gravity of the massive object around which the orbital path is established, the orbital motion can be influenced by by the gravity of other nearby objects. This is known as gravitational perturbation and can make orbits more complex. For example, the Moon is influenced by both Earth’s gravity and the Sun’s gravity, resulting in a slightly elliptical orbit around the Earth.

Types of orbits

Orbits are classified into several types according to their shape, inclination and specific characteristics. Among the most common are circular orbits, where an object maintains a constant distance from the central body, and elliptical orbits, which have variations in distance due to their oval shape. There are also parabolic and hyperbolic orbits, typical of objects that cross the solar system and are not gravitationally bound to the sun. On the other hand, orbits can be defined as low, medium or high depending on the altitude with respect to the surface of the central body, with low orbits being frequently used for earth observation satellites. These types of orbits are essential for understanding the behavior of both natural and artificial bodies in space.Orbits can also be influenced

Importance of orbits

Understanding orbits is crucial for space navigation and space mission planning. Scientists and space engineers use calculations and mathematical models to predict and control spacecraft orbits, ensuring that they stay on safe and efficient trajectories.

In addition to natural orbits, humans have succeeded in placing satellites in orbit around the Earth, which are used for various applications, such as communication, Earth observation, navigation, and scientific research.

The online orbit simulations on this page are an excellent way to delve deeper into orbital motion and the most important types of orbits. Give them a try!

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!

Orbit simulations

Gravity
Satellite

Gravity and orbits

In the first of our online orbit simulations, you can move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between the different celestial bodies and turn off gravity to see what would happen without gravity!

Trajectory of a satellite

The last of our online orbit simulations, allows us to observe how the trajectory of an artificial satellite over the Earth’s surface changes as its period and the inclination of its orbit change.

Motion
Motion II
Geostationary
Gravity

Orbital Motion

Orbital motions occur around an object that generates a centripetal force due to the effect of gravity. Is the net force acting on the satellite zero? Why doesn’t it fall?

Orbital Motion II

The satellite orbits the Earth under the influence of gravity. Check the relationship between the radius of gyration and circular velocity.

Geostationary Orbit

A satellite in a geostationary orbit rotates synchronously with the Earth. The geostationary orbit is located at about 36,000 km altitude in the plane of the equator. Check what happens as the radius or circular velocity changes.

Gravity and Orbits

In the latest of these online orbit simulations, you can move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between the different celestial bodies and turn off gravity to see what would happen without gravity!

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”

Edwin Powell Hubble

1889

–

1953

Edwin Hubble demonstrated the expansion of the universe and classified galaxies, establishing the foundations of modern observational cosmology

“Equipped with his five senses, man explores the universe”

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Giants of science

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

Isaac Newton

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”

Tycho Brahe

1546

–

1601

Tycho Brahe carried out highly precise astronomical observations before the telescope, developing a hybrid model between geocentrism and heliocentrism. His work was essential for Kepler

“The stars may shape destiny, but man observes their course”

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The Radio Sky II: Observational Radio Astronomy

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Test your knowledge

What is an orbit, and why is it a fundamental concept for understanding how objects move in space?

An orbit is the curved path that one object follows around another due to gravity. It is fundamental because it explains why planets, moons and satellites neither drift away into space nor fall directly toward the body that attracts them. In the solar system, for example, Earth orbits the Sun and the Moon orbits Earth in stable, repeating paths. Orbits can be nearly circular or slightly elongated, depending on the object’s speed and the strength of the gravitational pull. Understanding orbits helps explain everyday astronomical phenomena such as the movement of planets, the length of the year, the repetition of the seasons and the behavior of artificial satellites, which also remain in orbit because Earth’s gravity keeps them on a curved trajectory. For this reason, the concept of an orbit is essential for understanding how the nearby universe is structured and how celestial bodies move.

How do gravity and motion interact to keep planets, moons and satellites in their orbits?

Gravity pulls objects toward the most massive body, but at the same time those objects move forward with a certain speed. The combination of both effects creates a curved path: gravity constantly “pulls,” while the object’s motion prevents it from falling straight in. If a planet or satellite moved too slowly, it would fall toward the central body; if it moved too fast, it would escape into space. When the speed is just right, gravity keeps it following a stable orbit. This balance explains why Earth continues orbiting the Sun and why the Moon remains around Earth. It also allows artificial satellites to function: they are launched with the exact speed needed so that Earth’s gravity keeps them in a steady path. Thus, the interaction between motion and gravity is the key mechanism behind all orbital movement in the solar system.

Why doesn’t Earth fall into the Sun if the Sun is pulling it?

Because Earth is moving forward very fast at the same time the Sun pulls it inward. That combination creates a curved path instead of a fall. It’s like throwing a ball: if you throw it hard enough, it travels forward while gravity pulls it down. Earth moves so fast that it never reaches the Sun, and that’s why it stays in orbit.

Why are some satellites natural and others artificial?

Natural satellites, like the Moon, are objects that already existed and were captured by a planet’s gravity. Artificial satellites are built by humans and placed in orbit to do things like communication, observation or navigation. Both stay in orbit for the same reason: gravity keeps them following a curved path around the planet.

Why aren’t orbits perfect circles?

Because the object’s speed and the strength of gravity don’t always match perfectly to form a circle. Most of the time, the path is slightly stretched, forming an ellipse. Many orbits look almost circular, but technically they are a bit elongated.