Massive Gas cloud boomerangs back to our Milky Way – but don’t fret!

Chris Burns - Jan 29, 2016, 12:08 pm CST
Massive Gas cloud boomerangs back to our Milky Way – but don’t fret!

A beastly cloud of gas is headed towards our galaxy right this minute – but it won’t arrive for 30 million years. What’s interesting about this particular gas is not only that it’s traveling at 700,000 miles per hour, but that it’s been here before. This “Smith Cloud” as it’s called came from the Milky Way and to the Milky Way it will return – 70 million years ago it left, and 30 million years from now it’ll have swung around for the return.

Strange as it may seem, not all masses of gasses and planets and stars and all manner of bits and pieces in the universe are headed in a straight line. Gravity – along with movement of dark matter, scientists hypothesize here – causes clouds of gas like this one to move in and out of their origins.

Hubble views Smith Cloud traveling at 700,000 mph

In this case, the cloud took an extended arc out from the furthest regions of the Milky Way, turned, and is now headed back.

“Our galaxy is recycling its gas through clouds, the Smith Cloud being one example, and will form stars in different places than before,” said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland. Fox is the leader of the research team responsible for reporting this newest finding.

“Hubble’s measurements of the Smith Cloud are helping us to visualize how active the disks of galaxies are.”


Fox spoke with Discovery about the paper in which this set of findings is published.

“The cloud is an example of how the galaxy is changing with time,” said Fox. “It’s telling us that the Milky Way is a bubbling, very active place where gas can be thrown out of one part of the disk and then return back down into another.”

What, me worry?

The collision that’ll happen in 30 million years… first of all, you needn’t worry about the collision because you will no longer be alive. Second, while this collision will likely create a sun-forming explosion when it happens, it’ll be so far away from our own Solar System that we won’t be affected.

Not right away, anyway.

One would hope that by the time 30 million years rolls around, we’ll have found a way to move beyond our own Earth, anyway.


According to NASA‘s own Ashley Morrow, “The cloud is on a return collision course and is expected to plow into the Milky Way’s disk in about 30 million years. When it does, astronomers believe it will ignite a spectacular burst of star formation, perhaps providing enough gas to make 2 million suns.”

Nothing to freak out about!

You can learn more about the Smith Cloud in the research paper ON THE METALLICITY AND ORIGIN OF THE SMITH HIGH-VELOCITY CLOUD by Andrew J. Fox et al.. This paper was published by authors in the first Astrophysical Journal Letters issue of the year here in 2016 under code DOI: 10.3847/2041-8205/816/1/L11.

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