This soon-to-be famous image, courtesy of the Event Horizon Telescope (EHT), is our first picture of the black hole that sits inside Messier 87 (M87), a galaxy located more than 53 million light-years from Earth. It has a mass 6.5 billion times that of the sun.

This bright image was revealed by researchers at a number of worldwide press conferences today, and detailed in a set of papers in the Astrophysical Journal Letters. It shows visual evidence of the event horizon of a black hole and allow us to see something previously thought to be invisible.

“History books will be divided into the time before the image and after the image,” said Michael Kramer from the Max Planck Institute for Radio Astronomy in one of the press conferences.

But how do you take a picture of something that doesn’t radiate light? Well, rather than looking directly at the black hole itself, the EHT looks at gas surrounding it to take an image of its shadow. Specifically, researchers looked at the event horizon, the limit beyond which light can no longer escape the intense gravity of the black hole. The gas in this area heats up to billions of degrees, creating a silhouette whose shape should be predicted by Einstein’s theory of relativity. So far, the Event Horizon Telescope’s observations are in line with what he anticipated.

That shadow is revealed in the center of today’s picture against a backdrop of glowing light that is being pulled in by the black hole’s incredible gravity. You’ll notice one side of the image is actually brighter than the other. That is because of the black hole’s orientation relative to Earth. The brighter side is the one rotating toward Earth, meaning the particles are being thrown toward our planet faster on that edge, making them appear to glow brighter.