01 Gravity/

Experiment > Theory
How do celestial bodies warp the fabric of space-time and interact with each other?
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Runaway planet! That object’s velocity is faster than any nearby gravitational force.
How fast does a rocket need to travel to leave Earth? Any projectile must reach a speed of seven miles per second to break free of our planet’s gravity.
The gravity on Mars’ moon, Deimos, is so low that if you jumped you could reach escape velocity!
Your object attained escape velocity. Its initial kinetic energy was large enough to escape from the gravitational energy well of the larger object. Space probes that completely escape from the earth’s gravity and travel to other planets are examples of vehicles that achieve escape velocity.
You’ve created a binary system. These two celestial bodies weave around their common center of mass.
When you look up at the night sky, at least half of all the stars you see are binary stars orbiting one another.
You created an orbit. Orbits are like the Goldilocks of space, set in motion only when mass, distance, and velocity are just right. Orbits or often circular or elliptical. The earth's orbit around the sun, for example, deviates less than 2% from a circle.
Communications satellites aren’t the only man-made objects orbiting Earth. Astronauts have left behind tools, gloves, and other space junk that might still be floating around.
Typically comets have elliptical orbits. These “dirty snowballs” come from the outer edge of the solar system, pass near the sun where they start to melt and produce a long tail, then return to the edge of the solar system where they refreeze.
Your object failed to attain escape velocity. Its initial kinetic energy was too little to escape from the gravitational energy well of the larger object. Rockets and missiles that return to earth are examples of vehicles that do not achieve escape velocity.
During the early days of our solar system, there were lots of collisions. The scattered debris mostly formed back together or attached to planets.
Don’t worry. Nowadays our solar system is stable, and planets are unlikely to collide. However, you still need to watch for dangerous asteroids!
Some collisions don’t break things apart but leave impact craters. Mars has been shaped by impact. Its northern half is smooth and low, its southern half mountainous and rough -- so different they’re like two separate planets!
According to Newton, the larger the mass of objects and the shorter the distance between them, the stronger the attraction.
Objects move proportionately to their mass. Tiny planets move great distances. Massive planets may only wobble.
When slow-moving celestial bodies collide, they might fuse together and enlarge, increasing from a few kilometers to a few hundred kilometers in diameter.
Earth-like planets begin as particles formed from the collision of gas and dust and grow by accretion. A mature planet can take thousands or even millions of years to form.
Notice how the universe distorts when a object forms or grows in size? According to Einstein, all celestial bodies warp the fabric of space-time. The resulting curves are gravity.
Two celestial bodies of different masses have distinct effects upon space-time. A massive object creates a greater distortion of space-time and can shift the path of smaller objects if they're close enough.
Gravity penetrates everything and holds the galaxy together.
Everything in the universe - moons, planets, particles, galaxies, even light - is drawn towards everything else by the force of gravity.
Your planetary collision has created a moon, or natural satellite. Moons can be anywhere from centimeters to thousands of kilometers in width.
Over 4 billion years ago, something the size of Mars bumped into Earth and left behind the moon that orbits us.
Moons can also be captured by a hefty planet’s gravitational pull. The largest irregular moon in our solar system is thought to be Neptune’s moon, Triton, which originated in the Kuiper belt of comets.
Orbit shapes are typically ellipses. Orbiting objects zip towards a gravitational center and slow when pulling away.
An orbit system is a gravitationally-bound collection of celestial bodies.
The Sun is the center of planetary orbit in our solar system. But each planet has its own gravitational field, and most have their own natural satellites.
01 Gravity/

How do celestial bodies warp the fabric of space-time and interact with each other?


We tend think of gravity as a force of attraction, but it’s also been described as a curvature of space-time in the presence of mass. This National Science and Technology Medals Foundation interactive invites you to bend the fabric of space-time and observe the resulting gravitational forces. By adjusting the variables of mass, distance, and velocity, you can trigger orbits, collisions, and escape velocities in space.

NSTMF Laureates

The National Science and Technology Medals Foundation celebrates the amazing individuals who have won the highest science, technology, engineering, and mathematics award in the United States.

Jeremiah P. Ostriker

Studied the gravitational effects of dark matter.

John A. Wheeler

Popularized Einstein’s theory of relativity after WWII.

Edward Witten

Charted the topology of space-time.

Robert H. Dicke

Predicted the discovery of the Big Bang echo.

Allan R. Sandage

Discovered the first quasar.

Your universe has reached critical mass and collapsed. Fascinating!

Learn more about the pioneering scientists and thinkers behind this experiment at

Here are a few to check out: