Eric Burns

For seven hours straight, a space gamma-ray telescope registered flares that refused to end. That is how the story of GRB 250702B began: the longest gamma-ray burst ever observed. Typical bursts last seconds, rarely minutes. This one stretched to 25,000 seconds, beating the previous record by a factor of two.

Some explosions in space last only a few days, but at their peak they outshine entire galaxies. These are LFBOTs — rapid blue transients. They are rare and have been a mystery until now. Astronomers studied 11 such events.

A beacon at the edge of the galaxy blinks without a schedule: sometimes silent for years, sometimes emitting hundreds of flares in a single day. Such a beacon needs a watchman who never sleeps and never gets distracted.