Globular Cluster M3

Globular clusters are some of the best deep space objects to view with a video telescope setup.  These tightly bound swarms of stars orbit our Milky Way at a distance of 100,000 lights years or more and contain many more older stars than open clusters.  The density near the core of these stellar globules is very pronounced indeed, such that any inhabitants of a planet deep inside one would see a night sky peppered with incredibly bright stellar neighbours.  This artist impression from William Harris and Jeremy Webb illustrates the point beautifully.

glob inside

What the sky might look like inside globular cluster ’47 Tucana’ where nearly 600 thousand stars jostle within a volume of space only 120 light years across.

I planned to video the famous M3 globular tonight after seeing its relative high altitude and fortuitous position in SkySafari, and noting with some relief how clear and enticing the moonless sky looked.

After very little effort, and with a short 3 second integration time, I was able to watch this spectacular sight slowly materialise in the video monitor

M3

M3 contains over 500 thousand suns at a distance of 34 thousand light years from earth.

This image is incredibly bright and vibrant compared to naked eye views of M3 and is only slightly marred by a few visual artefacts due to the sensor technology.  The bloated white dots at the widest periphery of the image are not stars but hot spots due to the video chip heating up during long exposures.  Despite this I’m sure you’ll agree the view is a triumph of video observing, readily revealing the awesome density and structure of the cluster.

There are over 150 of these satellite clusters orbiting our Milky Way galaxy and their formation is the topic of excited debate.  The fact they harbour such a high proportion of older stars suggests they were some of the first stars to evolve within the overall galactic neighbourhood.

As far as the question of technological life existing within these systems, the chaos from closely interacting stars (on average only 1 light year apart) might prove an unfavourable environment.  Stars and planets in such a system would be under constant perturbation from nearby neighbours imparting gravitation ‘tugs’, resulting in unstable planetary orbits.

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