EarthSky // Science Wire, Space Release Date: Jan 08, 2014

A mysterious gas cloud with three times Earth’s mass is spiraling toward the supermassive black hole at the core of our Milky Way galaxy. Expect to hear about the encounter in the coming months.

Image via ESO/MPE/Marc Schartmann

Artist’s concept of gas cloud moving toward central Milky Way black hole, via ESO/MPE/Marc Schartmann

Here’s a story you’ll hear more about in the coming months. It’s the story of a mysterious gas cloud, known to astronomers as G2, discovered in 2011. The cloud is spiraling toward the supermassive black hole at the core of our home Milky Way galaxy. It was expected to encounter the black hole – which is called Sagittarius A* (pronounced Sagittarius A-star) – in late 2013. Now astronomers say to expect the encounter in the coming months, probably during Northern Hemisphere spring (Southern Hemisphere fall).

This cloud has about three times Earth’s mass. What will happen when it encounters the black hole? For us on Earth … nothing. Meanwhile, astronomers are even now anxiously watching for signs of the collision. Black holes, even supermassive black holes, are themselves invisible. No light can escape them. But as G2 spirals into Sagittarius A*, material falling into the hole will shine in X-rays.

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