What Happens After a Supernova Blows? Watch and Find Out

The years really fly by, don’t they? It seems like just yesterday that the Chandra and Hubble Space Telescopes released new observations of the Crab Nebula, creating a short but stunning time-lapse video of this iconic supernova remnant. But that was 2002 — and here we are, 22 years later, with a much-awaited sequel.

All these years later, the pulsar that powers the show is still doing its thing: The Manhattan-size star spins 30 times a second, releasing vast amounts of energy in the process and transforming the material around it. And the movie (which combines original footage with the sequel) is still surprisingly short — now showing 35 observations taken between 2000 and 2022 in about 5 seconds. But the details it reveals are incredible.

Deep inside the nebula, the pulsar powers a wind that flies out so fast, it makes a shock wave, visible as the bright inner circle in the video. That shock wave is a site of transformation, where the energy of the wind is transmitted to high-energy particles. Wisps of particles and light ripple outward from the ring.

Perpendicular to this equatorial wind, matter and anti-matter escape the pulsar at half the speed of light. The time-lapse shows the particle jet executing a slow, whip-like motion.

The Crab Nebula is one of only a few astronomical objects both bright and powerful enough for us to capture its motions on human timescales — particularly at X-ray energies. Another one is Cassiopeia A, the outflung veils of gas from a star that exploded some 340 years ago.

Chandra has previously imaged Cas A as well, but the newest release is a time-lapse that spans from 2000 to 2019 and includes a new processing technique to make full use of the data. It shows the outer layers of the one-time star as they expand in a jumble of motion. (The stellar remnant, a neutron star, is also visible in the X-ray images.)

Like in the Crab Nebula, the supernova exploded the outer stellar layers so fast that they made a shock wave. Here, too, the explosion’s energy is transformed, accelerating particles to near the speed of light.

As the shock wave slams into slower surrounding material (thrown out eons ago when the star was still bright), a second shock wave travels backward, like a traffic jam traveling backward from the scene of an accident on a highway.  As a result, some tendrils of gas appear to move in toward the neutron star even as others expand outward.