Radio bubbles.
Milky hourglass light-years tall,
black hole at its neck.
Scientists observing the centre of our galaxy have discovered a pair of radio-emitting bubbles stretching hundreds of light-years above and below the central region of the Milky Way.
To find this vast hourglass structure, Heywood et al (2019) conducted observations at wavelengths near 23 cm – dense clouds of dust block visible light from the centre of the galaxy but this form of radio emission allows scientists to see past the clouds.
At the centre of the Milky Way is a supermassive black hole. Most of the time it’s relatively calm but it can flare up when especially large amounts of dust and gas fall into it, a possible explanation for the radio bubble formation. An alternative suggestion for how the bubbles were created is a “massive burst of star formation”, according to researcher William Cotton at the National Radio Astronomy Observatory in Virginia and one of the co-authors of the paper. Regardless of how they were formed, the bubbles were created a few million years ago.
Original research: https://doi.org/10.1038/s41586-019-1532-5