An Electrifying View of the Heart of the Milky Way

Noise and chaos reign at the heart of the Milky Way, our home galaxy, or so it appears in an astonishing image captured recently by astronomers in South Africa.

The image, taken by the MeerKAT radio telescope, an array of 64 antennas spread across five miles of desert in northern South Africa, reveals a storm of activity in the central region of the Milky Way, with threads of radio emission laced and kinked through space among bubbles of energy. At the very center Sagittarius A*, a well-studied supermassive black hole, emits its own exuberant buzz.

We are accustomed to seeing galaxies, from afar, as soft, glowing eggs of light or as majestic, bejeweled whirlpools. Rarely do we glimpse the roiling beneath the clouds — all the forms of frenzy that a hundred million or so stars can get up to.

The image was captured and analyzed by a team of astronomers led by Ian Heywood of Oxford University and the South African Radio Astronomy Observatory. They published their results last week in the Astrophysical Journal.

MeerKAT is a precursor to the Square Kilometre Array, an immense set of antennas planned for construction in South Africa and Australia in the coming decade. When completed, it will be the most powerful radio telescope on Earth for the foreseeable future.

To visible-light telescopes, large sections of the Milky Way sky are rendered black by intervening clouds of cosmic dust. But radio waves pass right through, enabling MeerKAT to get up-close and personal.

“The best telescopes expand our horizons in unexpected ways,” Fernando Camilo, chief scientist at the South African Radio Astronomy Observatory and one of many co-authors of the new paper, said in a news release.

A close-up from a new image of the Milky Way.Credit…I. Heywood, SARAO

Another close-up shows a cloud known as G359.1-0.5, the glowing remains of a supernova explosion. To its left, the Mouse, a runaway pulsar possibly formed and ejected by the supernova. To its right, a radio-wave-emitting filament known as the Snake.Credit…I. Heywood, SARAO

Twenty separate observations, generating 70 terabytes of data and requiring three years of processing, were needed to produce the image. The result is a panorama 1,000 light-years wide and 600 light-years high of the central regions of the Milky Way. (The entire galaxy is 100,000 light years in diameter, and its center is 25,000 light-years from Earth.)

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