Giant Gas Cloud Plummeting Toward The Milky Way

Posted: Jan 29 2016, 3:49am CST | by , Updated: Jan 29 2016, 8:08pm CST, in News | Latest Science News


Giant Gas Cloud Plummeting Toward the Milky Way
This graphic shows how researchers used the Hubble Space Telescope to view three distant galaxies through the Smith Cloud, a technique that helped them determine the makeup of the cloud. Credit: NASA
  • Huge Gas Cloud on a Return Journey to the Milky Way

A huge gas cloud is on a return journey to the Milky Way.

The Smith Cloud, a large gas mass is moving towards the Milky Way with great speed. It is on the rebound and its exact composition is not known. This composition may provide clues as to its origins.

The latest evidence says that the cloud contains elements that resemble those found in our sun. It probably got generated in the Milky Way’s outer borders and not in its midst as some seem to think. 

Discovered for the first time in the 60s, the Smith Cloud has a lot of velocity and its orbit is fixed. This was known via radio telescopes. The gas cloud contains no stars and is moving at a speed of 700,000 miles per hour.

It will collide with the Milky Way disk in 30 million years. The size of this cloud, which is hardly visible, is equal to 30 moons. Thought to be some starless galaxy in the beginning, it was only when it was discovered that it was found that it didn’t contain hydrogen and helium.

That was when this hypothesis got revised. It in fact contains those heavier elements which are found in stars.   

This graphic shows the trajectory of the Smith Cloud falling into the Milky Way galaxy

The Hubble Space Telescope was used to analyze this phenomenon. The spectrograph showed the UV light from three active galaxies that lay beyond the gas cloud.

The Smith Cloud absorbs some of this light and by measuring it, an estimate was made of its chemical composition. Absorption from sulphur shows that heavier elements reside in the cloud.

The results show that the Smith Cloud is rich in sulphur like the Milky Way’s borders. This outer boundary line is some 40,000 light years from the center of the galaxy.

It is 15,000 light years away than the distance our sun and solar system happen to be from the center. Thus it probably has star stuff in it. It is by no means pure. The gas cloud is familiar with the conditions of the Milky Way. 

It was rejected by the Milky Way 70 million years ago and is boomeranging back today towards its origins. The day it strikes the Milky Way it may generate two million suns.

Several other cloud formations have been found too but their origins remain a riddle. The Smith Cloud is a clear example of the recycling of gaseous material in the universe. 

The study, titled “On the Metallicity and Origin of the Smith High-velocity Cloud,” was published this month in the Astrophysical Journal Letters.

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<a href="/latest_stories/all/all/20" rel="author">Sumayah Aamir</a>
Sumayah Aamir (Google+) has deep experience in analyzing the latest trends.




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