Our Milky Way galaxy is surrounded by an enormous halo of hot gas, Nasa astronomers have found.
It goes on for hundreds of thousands of light years - that's the time it'd take light to travel to the edge.
Scientists used information from Nasa's powerful space telescope Chandra to make the discovery.
They think the temperature of the halo is between 1 and 2.5 million kelvins - a few hundred times hotter than the surface of the Sun!
This new finding could help solve the "missing baryon" problem that's troubled astronomers for years.
Baryons are particles that make up most atoms found in the cosmos.
The number of particles that scientists have observed doesn't match the number there should be according to calculations.
But this latest discovery could account for some of those missing baryons.