The Great Hercules Globular Cluster M13

Posted by Kelly on October 16th, 2012

Great Hercules Globular Cluster

M13 is the Great Globular Cluster in Hercules

If you want to get someone hooked on observing, you have to do more than just show them the stars. While the moon and Saturn look great through a telescope, many astronomical objects need to be understood to be truly appreciated. There is nothing better than viewing a faint haze of light while someone tells you the fascinating story behind it. One such object that you can grab in the east before it sets until next spring is M13.

The globular cluster M13 in Hercules was discovered by Edmund Halley (of Halley’s comet fame) in 1714. Charles Messier cataloged the globular cluster in 1764. At magnitude 5.8, M13 can just barely be seen as a fuzzy patch with the unaided eye. M13 is one of about 140 globular clusters that orbit the Milky Way’s center.

In 1974, the Arecibo radio telescope sent a message toward M13 in the hopes of making contact with extraterrestrial life. The message will take approximately 25,000 years to reach M13, as the globular cluster is about 25,000 light-years distant from Earth.

If any alien life lived on a planet around one of the 300,000-some stars in M13, the sky would look bright even at night. With the crowd of stars surrounding it, inhabitants of M13 wouldn’t be able to see beyond the globular cluster to galaxies in the greater universe. A search for planets around another globular cluster, 47 Tucanae, turned up nothing.

Globular clusters are collections of older stars with less heavy metals and planet-forming material, making it unlikely that there is any life residing in them. Any planets that did form would probably have been thrown out of their orbit or destroyed by tidal interactions. So any message to M13 will likely fall on deaf ears. However, because of the rotation of the galaxy, M13 won’t even be in the right location to receive the message when it finally gets there. Perhaps some currently unknown star and planet system will be in just the right location and listening 25,000 years from now.


One person has commented

Brady Gates said,

In 15,000 years we’ll peobably have some thing that will get the message to M13 in almost 700 years 😉

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