Visiting a black hole? Allow plenty of time

200,000 years - at least

If you fancy taking a quick trip to the heart of a black hole be sure to allow plenty of time, since an international team of boffins has discovered that even the last leg of such a jaunt could take up to 200,000 years.

Yup, according to an investigation of the "internal motions of gas surrounding the nucleus of the active galaxy NGC1097" (47m light years distant in the southern constellation Fornax), "material as it descends into the core of a galaxy hosting a large black hole... will take about 200,000 years to make a one-way trip through the inner regions of the galaxy and into oblivion."

Or, in fact, longer than the average Northern Line tube trip from Edgeware to Stockwell, as our London readers will be amazed to read.

The team behind this revelation - made up of Thaisa Storchi-Bergmann, UFRGS, Brazil; David Axon and Andrew Robinson, RIT, USA; Alessandro Capetti, INAF-Turin, Italy, Alessandro Marconi, INAF-Florence, Italy; Rogemar Riffel, UFRGS, Brazil, and Claudia Winge, Gemini Observatory, Chile - used Chile's Gemini South Telescope and "sophisticated spectroscopic techniques" to probe clouds of material within 10 light years of the galactic centre - presumed home of the black hole.

Specifically, the scientists "measured the streaming motions toward the black hole by using two-dimensional spectroscopy to capture spectral data at several thousand points surrounding the nucleus of the galaxy". The technique is known as "integral field spectroscopy", which "takes light from many different parts of the telescope's field simultaneously and splits the light from each region into a rainbow or spectrum of light".

The upshot of it is, as team member Thaisa Storchi Bergmann of Brazil's Instituto de Fisica put it: "The resolution of this data is unprecedented when you look at how we were able to isolate so many different points around the nucleus of this galaxy and acquire a spectrum for each point at once.

"This paints an incredibly detailed picture of the region around the black hole and gives us a new glimpse at something we could only imagine before."

Project top dog Kambiz Fathi of Rochester Institute of Technology further explained: "It is the first time anyone has been able to follow gas this close to the supermassive black hole in the center of another galaxy.

"The work of our team confirms the main theories that have never been observationally confirmed at this level. We have been able to show that it is possible to measure these velocities down to these scales."

The velocity in question is, the team reckons, 52 kilometers (31 miles) per second - the speed at which spiral arms were pulling gas towards the nucleus at around 1,000 light years from the centre.

That's still a way out from the black hole's core, and a good few years from a final dateline with destiny. Fathi expands: "When we extrapolate our last data points, about 30 light-years from the black hole, this is where we find that it would take about 200,000 years for the gas to travel the last leg of its one-way journey to the supermassive black hole."

There's more background detail to the team's work in the press release here. The research findings will appear in a future issue of The Astrophysical Journal Letters. ®

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