Watch These Supernovas in (Time-Lapse) Motion

“The past is never dead,” William Faulkner once wrote. “It’s not even past.” Nobody knows this better than astronomers. Everything that has ever happened in the history of the universe has left a mark on the sky; with the right technology, much of it is now decipherable.

For the past quarter-century, NASA’s Chandra X-ray Observatory has been recording the roiling aftermath of two mighty supernova explosions that occurred hundreds of years ago, far out in space. This spring, the astronomers who operate Chandra combined its X-ray images into videos that document the evolution of two astrophysical landmarks: the Crab nebula, in the constellation Taurus, and Cassiopeia A, a gas bubble and hub of radio noise in the constellation Cassiopeia.

The videos show twisting, drifting ribbons of the remains of the star being churned by shock waves and illuminated by radiation from the dense, spinning cores left behind.

They were made to celebrate the 25th anniversary of the observatory, which was launched into space in 1999 and has been a workhorse of cosmology and astrophysics ever since.

The anniversary comes at a poignant moment. Earlier this year NASA proposed cutting Chandra’s operating funds. More than 700 astronomers signed a protest letter and created a website asking the agency to change its mind. Federal lawmakers from Massachusetts also joined the protest.

Lately things have been looking up. In July, a draft of a House appropriation bill for NASA’s 2025 budget expressed support for the continued operation of Chandra, “which continues to deliver discoveries addressing a wide range across astrophysics.”