The only thing more terrifying that someone saying “Look … a black hole!” is someone saying “Look … a black hole … and it sprung a leak!” That’s the strange message coming to us from the Hubble telescope – working again and sending scary photos to remind us why it’s still the reigning king of space telescopes until the James Webb one launches, deploys and proves itself. In the meantime, NASA reports that Hubble found evidence that Sagittarius A* -- the Milky Way’s supermassive black hole – is leaking a jet of hot gas. Is it time to find a giant cork … or a new galaxy?
"Our central black hole clearly surged in luminosity at least 1 millionfold in the last million years. That sufficed for a jet to punch into the Galactic halo."
That ready-for-Jeff-Goldblum-as-a-NASA-scientist movie line comes from Tsukuba University’s Alex Wagner, co-author of new research published in the Astrophysical Journal, explaining in a NASA press release how Sagittarius A* sprung a leak … if something which happened over a million years can be considered a ‘spring’. Wagner and Gerald Cecil of the University of North Carolina in Chapel Hill were studying data on Sgr A* from Hubble, NASA's Chandra X-ray Observatory, the Jansky Very Large Array telescope in New Mexico and the ALMA Observatory in Chile when they noticed an expanding, narrow linear jet of molecular gas 15 light-years away from the black hole. Hubble infrared-wavelength images showed a glowing, inflating bubble of hot gas aligned to the jet at a distance of at least 35 light-years from the black hole. Wagner paints a better picture.
"The streams percolate out of the Milky Way's dense gas disk. The jet diverges from a pencil beam into tendrils, like that of an octopus."
(Composite views of the leaking gas can be seen here.) While Sgr A* is said to be in a powered down state at the moment, it apparently still shows signs of activity when something gets sucked into its supermassive mouth and it belches out some gas. Unfortunately, the leak can’t be seen until it powers up again, but Cecil says that will happen soon … and it will be “cool.”
“The black hole need only increase its luminosity by a hundredfold over that time to refill the jet channel with emitting particles. It would be cool to see how far the jet gets in that outburst.”
When you’re an astronomer, you get your kicks wherever you can. The next step for the team is to use the Event Horizon Telescope (EHT), an international collaboration capturing images of black holes using a virtual Earth-sized telescope, to take images of the black hole's shadow which may show where and how the leak is launched.
In the meantime, Hubble will keep sending back its fantastic images until the James Webb telescope gets its act together.