“Immediately – even if we’re on the road somewhere – we’ll go to our laptops, log in and then get on the phone to teleconference with other members of the team,” says Gehrels. Within 15 minutes of the burst, they will have issued an alert so that other observatories on the ground can point their telescopes towards the source.

Like being a doctor on call, duty scientists working on Swift even get woken up in the middle of the night to react to an event on the other side of the cosmos. “It’s really exciting, you’re making discoveries and learning something new at all hours of the day and night.”

Black holes and revelations

However, not everyone agrees with this assessment. “My wife was amused by this at the beginning, pretty soon it got to be annoying,” says Gehrels. “As more time went on, she’d just sleep right through it.”

Before Swift was launched, no one knew for sure what caused gamma ray bursts. Now astronomers are fairly certain that the longer bursts – that is anything over two seconds – are caused when the centre of massive stars collapse in on themselves forming black holes. When the stars subsequently explode into oblivion, a jet of gamma rays is blasted out across space.