Messier 13
Encyclopedia
Messier 13 or M13 is a globular cluster
of about 300,000 stars in the constellation
of Hercules
.
in 1714, and catalogued by Charles Messier
on June 1, 1764.
It is located at right ascension
16h 41.7m and declination
+36° 28'. With an apparent magnitude
of 5.8, it is barely visible with the naked eye
on a very clear night. Its diameter is about 23 arc minutes and it is readily viewable in small telescopes. Nearby is NGC 6207, a 12th magnitude edge-on galaxy that lies 28 arc minutes directly north east. A small galaxy, IC 4617, lies halfway between NGC 6207 and M13, north-northeast of the large globular cluster's center.
, and it is composed of several hundred thousand star
s, the brightest of which is the variable star
V11 with an apparent magnitude of 11.95. M13 is 25,100 light-years away from Earth
.
of 1974, designed to communicate the existence of human life to hypothetical extraterrestrial
s, was transmitted toward M13. The reason was that with a higher star density, the chances of a life harboring planet with intelligent life forms, were believed to be higher. Even though the message was transmitted, M13 will no longer be in that location when it arrives. The sending of the message was more of a technological demonstration, rather than an actual attempt to contact life.
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
of about 300,000 stars in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Hercules
Hercules (constellation)
Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
.
Discovery and visibility
M13 was discovered by Edmond HalleyEdmond Halley
Edmond Halley FRS was an English astronomer, geophysicist, mathematician, meteorologist, and physicist who is best known for computing the orbit of the eponymous Halley's Comet. He was the second Astronomer Royal in Britain, following in the footsteps of John Flamsteed.-Biography and career:Halley...
in 1714, and catalogued by Charles Messier
Charles Messier
Charles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects"...
on June 1, 1764.
It is located at right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
16h 41.7m and declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
+36° 28'. With an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 5.8, it is barely visible with the naked eye
Naked eye
The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...
on a very clear night. Its diameter is about 23 arc minutes and it is readily viewable in small telescopes. Nearby is NGC 6207, a 12th magnitude edge-on galaxy that lies 28 arc minutes directly north east. A small galaxy, IC 4617, lies halfway between NGC 6207 and M13, north-northeast of the large globular cluster's center.
Characteristics
M13 is about 145 light-years in diameterDiameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
, and it is composed of several hundred thousand star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s, the brightest of which is the variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
V11 with an apparent magnitude of 11.95. M13 is 25,100 light-years away from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
Arecibo message
The Arecibo messageArecibo message
The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...
of 1974, designed to communicate the existence of human life to hypothetical extraterrestrial
Extraterrestrial life
Extraterrestrial life is defined as life that does not originate from Earth...
s, was transmitted toward M13. The reason was that with a higher star density, the chances of a life harboring planet with intelligent life forms, were believed to be higher. Even though the message was transmitted, M13 will no longer be in that location when it arrives. The sending of the message was more of a technological demonstration, rather than an actual attempt to contact life.
Literary references
- The science fictionScience fictionScience fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
novellas "Sucker BaitSucker BaitSucker Bait is a science fiction novella by Isaac Asimov. It was first serialized in the February and March 1954 issues of Astounding Science Fiction, and reprinted in the 1955 collection The Martian Way and Other Stories...
" by Isaac AsimovIsaac AsimovIsaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...
and "Question and AnswerQuestion and AnswerQuestion and Answer is a science fiction novel by Poul Anderson that originally appeared in the June and July 1954 issues of Astounding Science Fiction...
" by Poul AndersonPoul AndersonPoul William Anderson was an American science fiction author who began his career during one of the Golden Ages of the genre and continued to write and remain popular into the 21st century. Anderson also authored several works of fantasy, historical novels, and a prodigious number of short stories...
take place on Troas, a world within M13. - In the science fiction series Perry RhodanPerry RhodanPerry Rhodan is the name of a science fiction series published since 1961 in Germany, as well as the name of the main character. It is a space opera, dealing with several themes of science fiction. Having sold over one billion copies worldwide, it is the most successful science fiction book series...
, M13 is the location of Arkon, the home world of the race of Arkonides. - In author Dan Simmon's Hyperion CantosHyperion CantosThe Hyperion Cantos is a series of science fiction novels by Dan Simmons. Set in the far future, and focusing more on plot and story development than technical detail, it falls into the soft science fiction category...
the Hercules cluster is where Earth was secretly moved to after it was supposedly destroyed. - In The Sirens of TitanThe Sirens of TitanThe Sirens of Titan is a Hugo Award-nominated novel by Kurt Vonnegut, Jr., first published in 1959. His second novel, it involves issues of free will, omniscience, and the overall purpose of human history...
, Kurt VonnegutKurt VonnegutKurt Vonnegut, Jr. was a 20th century American writer. His works such as Cat's Cradle , Slaughterhouse-Five and Breakfast of Champions blend satire, gallows humor and science fiction. He was known for his humanist beliefs and was honorary president of the American Humanist Association.-Early...
writes "Every passing hour brings the Solar System forty-three thousand miles closer to Globular Cluster M13 in Hercules -- and still there are some misfits who insist that there is no such thing as progress." - Deliberately engineering a star in Messier 13 to go nova was part of the Cybermen’s complicated plot in the 1968 Doctor WhoDoctor WhoDoctor Who is a British science fiction television programme produced by the BBC. The programme depicts the adventures of a time-travelling humanoid alien known as the Doctor who explores the universe in a sentient time machine called the TARDIS that flies through time and space, whose exterior...
story The Wheel in SpaceThe Wheel in SpaceThe Wheel in Space is a serial in the British science fiction television series Doctor Who, which originally aired in six weekly parts from 27 April to 1 June 1968...
. - In Bill AmendBill AmendWilliam J. C. "Bill" Amend III is an American cartoonist, best known for his comic strip FoxTrot.-Early life:Amend attended high school in Burlingame, California where he was a cartoonist on his school newspaper. Amend is an Eagle Scout in the Boy Scouts of America. He attended Amherst College,...
's popular comic strip FoxTrot, Jason Fox mentions observing the M13 Globular Cluster
External links
- Messier 13, SEDS Messier pages
- Messier 13, Galactic Globular Clusters Database page
- Messier 13, High-resolution LRGB image based on 2 hrs total exposure
- M13 Hercules Globular photo detail Dark Atmospheres
- Messier 13, Image by Waid Observatory
- NightSkyInfo.com - M13, the Hercules Globular Cluster
- Photometric study of the V2 cepheid in M13
- Period, Amplitude and Light Curve of V38 in M13
- Great Globular Cluster in Hercules (Messier 13/NGC 6205)