Black Hole Explorer

A black hole is a place in space where gravity is so strong that nothing, not even light, can escape from it. It usually forms when a very big star dies and collapses.

Yes — it is 100% free with no signup. Everything runs in your browser.

It is a simplified but physics-based simulation of a non-spinning (Schwarzschild) black hole. The way light bends around it uses Einstein’s general relativity. The look and brightness of the glowing disk are artistic.

The event horizon is the point of no return around a black hole. Anything that crosses it, even light, can never come back out.

It is called the accretion disk. Gas and dust spin around the black hole and get squeezed and heated to millions of degrees, so they glow brightly.

Gravity bends the path of light like a giant lens. Light from the back of the disk curves around the black hole, so you can see it above and below the dark shadow.

It is a thin bright ring very close to the dark shadow. It is made by light that has travelled around the black hole once or more before reaching your eyes.

The disk spins very fast. The side moving toward you looks brighter and the side moving away looks dimmer. This is called Doppler beaming and is like a siren sounding louder as it comes closer.

The camera dives toward the black hole. The readout shows how time slows down for you compared with someone far away, called gravitational time dilation. When you cross the event horizon the screen goes dark, because nobody knows for sure what happens inside.

Far away, a black hole pulls just like any other object of the same mass. If the Sun suddenly became a black hole, Earth would keep orbiting the same way, though it would be dark and cold.

The Earth would have to shrink to about the size of a peanut (radius around 9 mm) and the Sun to about 3 km. The calculator in the tool shows this and more using r = 2GM / c².

Sagittarius A* is the supermassive black hole at the centre of our galaxy, about 4 million times the mass of the Sun. M87* is a much bigger one in another galaxy and was the first black hole ever photographed, in 2019.

Yes. Use the EN / हिं button in the corner to switch the tour, quiz, calculator and controls between English and Hindi.

The black hole is drawn in real time by your graphics chip, which is demanding. Choose Low quality in the controls. The tool also lowers the quality by itself if it detects a slow frame rate.

Yes, on phones that support WebGL. Drag with one finger to look around and pinch to move closer or farther. Use Low quality on older phones.

Yes. Use the camera button to save the current view as a PNG, or the fullscreen button for a bigger view.