A strange anecdote concerning Messier 13, can be found at Wikipedia:

“The Arecibo message of 1974, which contained encoded information about the human race, DNA, atomic numbers, Earth's position and other information, was beamed from the Arecibo Observatory radio telescope towards M13 as an experiment in contacting potential extraterrestrial civilizations in the cluster. However, the experimenters intentionally sabotaged their goal: the message will reach the cluster's past position in 25,000 years. By then, the cluster will occupy a different position in space; it will never receive the message.”

EDIT 12/17/2014 : Thanks for selecting the image for IOTD. Credit goes to all the people who shared their images using a CC license!

The image is a Crowd Image. It’s made by combining almost 300 different images of M13 found on the internet. The method is described in more detail in some of the other Crowd Images in my gallery.

If you want to have your images included in future Crowd Image projects, please update your license (action menu) to something like CC BY-NC, or drop me a PM, and I’ll put you on the list of people who have kindly given me permission to use their work. Thanks in advance!

The integration time is calculated from an average of 50 random samples.

Image credits (thanks for sharing!)

A. Tag, Abel de Burgos, Adam Evans, aknotwot, Alun Salt, Alvinillo, André Lucas Melo, Angel Requena, Armelle & Eric, AstroGG, Astrowoosie, Barry Brook, Ben Ritchie, bilbo-le-hobbit, Bob Star, buscettn, Cars10s PhoToes, Charlie Prince, ched cheddles, chripell, Chris Isherwood, Chris Madson, Cosmosium, Creedence, cristiano.c, D Lillis, D Lillis, Dan Watt, dave halliday, David Warrington, Davide Simonetti, deadlydude, dkuchta5, Eric Holmes, Ferran Ginebrosa, Flavastro, Florian Meyer, fphg, fragro, FranckIM06, Fred Locklear, Fritz, g8ey_m, Gary Gause, geco71, Haramir, irvandestadt, Jan Curtis, Janos Barabas, Jared Smith, Jason Tackett, Javier R., Jay Cross, jdiwnab, Jeff Tropeano, Jérôme Béguin, john.purvis, Jörg Weingrill, Jose Carlos Castro, jpstanley, Juan Lozano, Ken_Lord, Kirchhainer Sternfreunde, Kjetil Fjellheim, Kristian Urdal, LE DALL, lio grey, Luca Argalia, Luca Billeri, Luca Malossi, Luigi Fontana, M.W.Hoy, MacRoAstro, makelessnoise, Mark Mathosian, mat's eye, matted69, Matthias, maxgaspa, Máximo Bustamante, maxou9914, Michele Fabrizio, Michele Palma, Mike Durkin, Mike G, Miquel, Morten Balling, Morten la Cour, Neb_34, Oo_void, Patrick Denker, PaulHutchinson, Pete Collins, Peter Williamson, Philippe Garcelon, Phillip Seeber, Piotr Ambroziak, pisto92, PoGo, Prabhakar, Preis Alois, Ralph W, Ram Viswanathan, Ramon, Ramon Casha, Richard Pattie, Richie Jarvis, RIKY, s58y, Salvatore Iovene, Salvopa, senscience, Sergei Golyshev, Shane Poage, si_63, skyborg, Stan Weber, Stefano Giardinelli, Stephen Rahn, Steve, Steve Elliott, Steve Yan, TheBreed, thlalomi, Tim, Tino Leichsenring, toineg, Tomofwight, Valts Treibergs, Vipula De Silva, Vojtěch Kudela, Walliang Jacques, zemt-fr, Zoeff.