Nasa scientists spot mystery giant 'space bubbles' either side of the Milky Way



They stretch across more than half of the sky and are as large as the Milky Way - but nobody knows how they got there.

NASA scientists have been left scratching their heads after discovering two huge bubbles of gamma rays either side of our galaxy.

At 50,000 light years tall together, they extend from the constellation Virgo to the constellation Grus and are among the largest such structures ever found.

Two colossal bubbles of high-energy radiation are emanating from the Mily Way's core - and scientists have no idea why

The discovery has reminded experts that however much we know about the galaxy, it is always full of surprises.

But they have also tried their best to explain how they got here - one theory is that they have been fuelled by a wave of star births and deaths at the centre of the Milky Way.

Other researchers have suggested it might be connected with the huge black hole which sits at the centre of the galaxy.

The bubbles were found by NASA’s Fermi Gamma-Ray Telescope, which scans the sky every three hours for high energy light.

‘This result is very exciting,’ said Fermi scientist Simona Murgia, with the SLAC National Accelerator Laboratory in California.

‘These features could reveal unexpected and very important physical processes in our galaxy that until now we knew nothing about, despite the fact that these features could possibly be almost as large as the Milky Way and might have been around for millions of years.’

A space map showing the two patches of gamma rays above and below our galaxy

David Spergel, an astrophysicist at Princeton who was not involved in the work, added: ‘Wow. And we think we know a lot about our own galaxy’.

The bubbles contain the energy equivalent to 100,000 supernova explosions, leading to NASA ruling out dark matter, which makes up a quarter of the universe.

One theory being explored is that the supermassive black hole at the centre of the Milky Way may have had some kind of outburst.

‘You have to ask where could energy like that come from,’ said astronomer Doug Finkbeiner, from the Harvard-Smithsonian Center for Astrophysics.

‘We know it didn't get to be that big by sitting there quietly all the time. It certainly has had big accretion events in the past, where material falls on it and then some of that material comes back out as high-energy particles blasted out in the form of a jet.

‘We've never really seen very good evidence of it. This might be the first evidence for a major outburst of the black hole at the center of the galaxy.

