An illustration of a gamma-ray burst that lasted for 27 days. (Image credit: Robert Lea)

Astronomers have spotted a remarkable gamma-ray burst (GRB) that's a real Incredible Hulk compared to other cosmic explosions of the same type.

What makes this GRB so special is the fact that the central engine powering it remained active for around 27 days, flaring in X-rays following the initial blast. That's 20 days longer than the longest previous GRB on record.

This record-breaking burst — which is designated GRB 220706A and was spotted on July 6, 2022 — is even more exciting because scientists don't know what the central engine powering it actually is.

"In a nutshell, GRB 220706A is an extremely late X-ray flare.…