Talk:Messier 13

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Shouldn't the comment at the bottom of the page be, like, here?

Re: Arecibo Message We read: "Even though the message was transmitted, M13 will no longer be in that location when it arrives".

Intelligent life on earth should consider this and direct the message into that future direction!  :-))

--Hans W (talk) 15:20, 9 August 2010 (UTC)

Are you sure? The distance to the cluster is 25,100 light years, so it will take that long to arrive. For the cluster to have shifted by 27 parsecs (84 ly) in that time, I think it would need to have a transverse velocity of:
\begin{smallmatrix} \frac{27\ \text{pc} \times (3.1 \times 10^{13}\ \text{km/pc})}{(2.5 \times 10^4\ \text{years}) \times (3.2 \times 10^7\ \text{seconds/year})}\ \approx\ 1,000\ \text{km/s} \end{smallmatrix}
Hence it would need to be moving faster than the escape velocity for the Milky Way (~310 km/s). Regards, RJH (talk) 17:14, 14 January 2012 (UTC)

What would be the average distance between stars in the cluster? That would be an interesting Fact to mention in the article. (talk) 13:46, 7 January 2012 (UTC)

It varies by distance from the core. The article could probably list a core density though. Regards, RJH (talk) 17:14, 14 January 2012 (UTC)

Local Group[edit]

I'm no expert, but M13's distance from us suggests it's in the Milky Way's Local Group. If so, this should be mentioned in the article. Perhaps M13 should also be added to the List of Milky Way's satellite galaxies. Cheers (talk) 04:18, 11 June 2014 (UTC)