Solar System Chatter

Swinging Back Around

NASA, ESA, and A. Feild/A. Fox (STScI)
NASA, ESA, and A. Feild/A. Fox (STScI)
Around 70 million years ago, the Milky Way ejected a cloud of gas and dust. Like a baseball thrown into the sky, that cloud is headed back for us, and is predicted to crash into our galaxy in another 30 million years. It’s called the Smith Cloud, named after Gail Smith, who discovered it as an astronomy student in the 1960s. Scientists have recently been able to use the Hubble Space Telescope to see what elements make up the cloud. Since it contains heavy elements, like those created in massive stars, astronomers deduced that the cloud was produced here, rather than just being a rogue gas cloud, which would have been made primarily of helium and hydrogen. When it plows back through our galaxy at 700,000 miles per hour, the comet-shaped cloud (11,000 light-years long and 2,500 across) could shake up the Milky Way enough to produce 2 million new stars.

Heather Goss is the Departments Editor at Air & Space.

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