Gas Cloud on Collision Course with the Milky Way

by Fraser Cain on January 11, 2008

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Smith
Don’t panic, but there’s a giant cloud of hydrogen gas on a collision course with the Milky Way. When it hits, 40 million years from now, it should generate vast regions of star formation. In fact, we don’t even need to wait; the leading edge of this gas cloud is already starting to interact with our galaxy. The fireworks are about to begin.

The cloud is called Smith’s Cloud, after the astronomer who discovered it in 1963. It’s 11,000 light-years long and 2,500 light-years wide, and contains enough hydrogen to make a million stars with the mass of the Sun.

Felix J. Lockman, of the National Radio Astronomy Observatory (NRAO) announced their latest observations of Smith’s Cloud at the Winter meeting of the American Astronomical Society in Austin, Texas. According to Lockman, the cloud is located 8,000 light-years from the Milky Way’s disk, and hurtling towards us at 240 km/second (150 miles/second).

“This is most likely a gas cloud left over from the formation of the Milky Way or gas stripped from a neighbor galaxy. When it hits, it could set off a tremendous burst of star formation. Many of those stars will be very massive, rushing through their lives quickly and exploding as supernovae. Over a few million years, it’ll look like a celestial New Year’s celebration, with huge firecrackers going off in that region of the galaxy,” Lockman said.

Until this latest research, astronomers were never sure if Smith’s Cloud was actually part of the Milky Way, being blown out of the galaxy, or something falling in.

Lockman and his colleagues made 40,000 individual pointings of the Green Bank radio telescope to pull together the data for their observations. This was necessary because the cloud is so vast.

“If you could see this cloud with your eyes, it would be a very impressive sight in the night sky,” Lockman said. “From tip to tail it would cover almost as much sky as the Orion constellation. But as far as we know it is made entirely of gas – no one has found a single star in it.”

Original Source: NRAO News Release

About 

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

Chuck Lam January 12, 2008 at 9:59 AM

Why would star formation in the cloud wait until interaction with our galixy? Why isn’t star formation occuring thorought the cloud now?

Ron January 12, 2008 at 5:44 AM

This is just cool. i love your blog, keep on the good work.

Rev. January 12, 2008 at 7:23 AM

Something is gonna’ get us before that thing arrives, probably our politices and the Bush’s New World Order.

Thanks Lockman, an interesting observation.

alfonso padilla January 12, 2008 at 7:48 AM

really cool post.
would this star formation affect the stars we see in the sky? you know if you where there 40 million years from now?

Josh M. January 12, 2008 at 1:46 PM

Maybe God pooted? : )

Antti o January 12, 2008 at 1:54 PM

This gives really a new sight to the creation of the universe we know. It did’t stop in the Big Bang and development just after that but keeps on. That makes you wonder whether how many cycles have already passed before this universe…

jairo January 12, 2008 at 10:24 PM

nice! it’s very interesting! : ]

Russell January 13, 2008 at 6:15 PM

Back in 1957, cosmologist Fred Hoyle wrote a novel (The Black Cloud) about an intelligent cloud of gas that entered the galaxy, then the Solar System.

Could this be it??

Hoyle describes the arrival near the Earth of a small interstellar cloud that can think and move of its own accord. A living organism, half a billion years old, as big as the orbit of Venus, and as massive as Jupiter, the Black Cloud has a “brain” that consists of complex networks of molecules which can be increased in number and specialization as the creature desires

see http://www.daviddarling.info/encyclopedia/B/BlackCloud.html

K. Tarbert January 13, 2008 at 9:44 PM

Fascinating! Another thought– could this be the remainder of some supermassive star supernova or run in with another to leave a gaseous nebula on the greyhound track out there? I can’t really imagine this big an event, but I have seen some really unbelievable things like this coming to light lately. Is it even possible in theory?

John January 14, 2008 at 12:10 AM

So it hits 40 million years from now? I guess I won’t wait up tonight to watch.

Fascinating stuff!

Lohit January 14, 2008 at 12:11 AM

This is really interesting… The News is all over the place…. before it happens i.e 40 million years.. i think humans will be prepared 4 it… is this cloud visible wit naked eye.. or u have to use some telescope 2 view this thing…. and i would like 2 knw d exact postion

Akbar Ahmed January 14, 2008 at 7:15 AM

Since the Universe is rotating, I wonder how can galaxies collide. Galaxies ought be be receeding from each other

Akbar Ahmed January 14, 2008 at 7:27 AM

Arent galaxies supposed to be receeding from each other?.
How can they collide

pedro varon January 14, 2008 at 7:50 AM

In 40 million years when the cloud hits the milkyway, what would be the location of the sun? What part of the galaxy will it hit first? is our local group of stars at risk?

Peter K January 14, 2008 at 12:25 PM

Akbar,

Galaxies, in general, are receding from each other as the universe expands. I haven’t heard any indication that the universe is rotating…what frame of reference would we have? However, within galaxy clusters, and amongst groups within those clusters, galaxies react to gravity or whatever other forces act on them. The Andromeda galaxy, our twin, is coming at us at 300km/s (thereabouts). We absorbed the smaller Sagittarius Galaxy millions of years ago. Galaxies evolve. The universe is not done by any means, This is not the universe you’ll see in half a billion years.

Peter K January 14, 2008 at 12:30 PM

It would take the existing stars of the Milky Way to disturb this cloud into collapsing to create any new stars or enough density to affect the galaxial arms. If it blew through this solar system, it probably wouldn’t make any particular difference at all. It’s still more of a vacuum than scientists make in a lab. In it’s entirety, it’s huge, but taken in chunks, it’s barely there.

Themistoklis January 18, 2008 at 7:53 AM

if we are expanding as a Universe then, we are not receding. If we are expanding and receding as a Universe then again, we are in a collision course with another…. Universe. Nobody can verify [within our Galaxy] the Andromeda’s existence 2,000 years ago and we just discovered the Smith’s gaseous cloud using state of the art satellite telescope. We have much more to learn, Also we have so little time to enjoy and convert our knowledge to reality!

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