Full panoramic view of the constellations near the Milky Way by Matt Dieterich
What comes to mind when you look up at the night sky and spot the constellations? Is it a grand desire to explore deep into space? Is it the feeling of awe and wonder, that perhaps these shapes in the sky represent something? Or is the sense that, like countless generations of human beings who have come before you, you are staring into the heavens and seeing patterns? If the answer to any of the above is yes, then you are in good company!
While most people can name at least one constellation, very few know the story of where they came from. Who were the first people to spot them? Where do their names come from? And just how many constellations are there in the sky? Here are a few of the answers, followed by a list of every known constellation, and all the relevant information pertaining to them.
Definition:
A constellation is essentially a specific area of the celestial sphere, though the term is more often associated with a chance grouping of stars in the night sky. Technically, star groupings are known as asterisms, and the practice of locating and assigning names to them is known as asterism. This practice goes back thousands of years, possibly even to the Upper Paleolithic. In fact, archaeological studies have identified markings in the famous cave paintings at Lascaux in southern France (ca. 17,300 years old) that could be depictions of the Pleiades cluster and Orion’s Belt.
There are currently 88 officially recognized constellations in total, which together cover the entire sky. Hence, any given point in a celestial coordinate system can unambiguously be assigned to a constellation. It is also a common practice in modern astronomy, when locating objects in the sky, to indicate which constellation their coordinates place them in proximity to, thus conveying a rough idea of where they can be found.
Closeup of the Lascaux cave paintings, showing a bull and what could be the Pleiades Cluster (over the right shoulder) and Orion’s Belt (far left). Credit: ancient-wisdom.com
The word constellation has its roots in the Late Latin term constellatio, which can be translated as “set of stars”. A more functional definition would be a recognizable pattern of stars whose appearance is associated with mythical characters, creatures, or certain characteristics. It’s also important to note that colloquial usage of the word “constellation” does not generally differentiate between an asterism and the area surrounding one.
Typically, stars in a constellation have only one thing in common – they appear near each other in the sky when viewed from Earth. In reality, these stars are often very distant from each other and only appear to line up based on their immense distance from Earth. Since stars also travel on their own orbits through the Milky Way, the star patterns of the constellations change slowly over time.
History of Observation:
It is believed that since the earliest humans walked the Earth, the tradition of looking up at the night sky and assigning names and characters to them existed. However, the earliest recorded evidence of asterism and constellation-naming comes to us from ancient Mesopotamia, and in the form of etchings on clay tablets that are dated to around ca. 3000 BCE.
However, the ancient Babylonians were the first to recognize that astronomical phenomena are periodic and can be calculated mathematically. It was during the middle Bronze Age (ca. 2100 – 1500 BCE) that the oldest Babylonian star catalogs were created, which would later come to be consulted by Greek, Roman and Hebrew scholars to create their own astronomical and astrological systems.
Star map showing the celestial globe of Su Song (1020-1101), a Chinese scientist and mechanical engineer of the Song Dynasty (960-1279). Credit: Wikipedia Commons
In ancient China, astronomical traditions can be traced back to the middle Shang Dynasty (ca. 13th century BCE), where oracle bones unearthed at Anyang were inscribed with the names of star. The parallels between these and earlier Sumerian star catalogs suggest they did no arise independently. Astronomical observations conducted in the Zhanguo period (5th century BCE) were later recorded by astronomers in the Han period (206 BCE – 220 CE), giving rise to the single system of classic Chinese astronomy.
In India, the earliest indications of an astronomical system being developed are attributed to the Indus Valley Civilization (3300–1300 BCE). However, the oldest recorded example of astronomy and astrology is the Vedanga Jyotisha, a study which is part of the wider Vedic literature (i.e. religious) of the time, and which is dated to 1400-1200 BCE.
By the 4th century BCE, the Greeks adopted the Babylonian system and added several more constellations to the mix. By the 2nd century CE, Claudius Ptolemaus (aka. Ptolemy) combined all 48 known constellations into a single system. His treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come.
Between the 8th and 15th centuries, the Islamic world experienced a burst of scientific development, reaching from the Al-Andus region (modern-day Spain and Portugal) to Central Asia and India. Advancements in astronomy and astrology closely paralleled those made in other fields, where ancient and classical knowledge was assimilated and expanded on.
The Northern Constellations. Credit: Bodel Nijenhuis Collection/Leiden University Library
In turn, Islamic astronomy later had a significant influence on Byzantine and European astronomy, as well as Chinese and West African astronomy (particularly in the Mali Empire). A significant number of stars in the sky, such as Aldebaran and Altair, and astronomical terms such as alidade, azimuth, and almucantar, are still referred to by their Arabic names.
From the end of the 16th century onward, the age of exploration gave rise to circumpolar navigation, which in turn led European astronomers to witness the constellations in the South Celestial Pole for the first time. Combined with expeditions that traveled to the Americas, Africa, Asia, and all other previously unexplored regions of the planet, modern star catalogs began to emerge.
IAU Constellations:
The International Astronomical Union (IAU) currently has a list of 88 accepted constellations. This is largely due to the work of Henry Norris Russell, who in 1922, aided the IAU in dividing the celestial sphere into 88 official sectors. In 1930, the boundaries between these constellations were devised by Eugène Delporte, along vertical and horizontal lines of right ascension and declination.
The IAU list is also based on the 48 constellations listed by Ptolemy in his Almagest, with early modern modifications and additions by subsequent astronomers – such as Petrus Plancius (1552 – 1622), Johannes Hevelius (1611 – 1687), and Nicolas Louis de Lacaille (1713 – 1762).
The modern constellations, color-coded by family, with a dotted line denoting the ecliptic. Credit: NASA/Scientific Visualization Studio
However, the data Delporte used was dated to the late 19th century, back when the suggestion was first made to designate boundaries in the celestial sphere. As a consequence, the precession of the equinoxes has already led the borders of the modern star map to become somewhat skewed, to the point that they are no longer vertical or horizontal. This effect will increase over the centuries and will require revision.
Not a single new constellation or constellation name has been postulated in centuries. When new stars are discovered, astronomers simply add them to the constellation they are closest to. So consider the information below, which lists all 88 constellations and provides information about each, to be up-to-date! We even threw in a few links about the zodiac, its meanings, and dates.
A chart of the constellations and signs that make up the zodiac. Credit: NASA
Did you know that there are 88 constellations in the night sky? Over the course of several thousand years, human beings have cataloged and named them all. But only 12 of them are particularly famous and continue to play an active role in our astrological systems. These are known as the zodiac signs, 12 constellations that correspond to the different months of the year.
Each of these occupies a sector of the sky which makes up 30° of the ecliptic, starting at the vernal equinox – one of the intersections of the ecliptic with the celestial equator. The order of these astrological signs is Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces. Here are all the zodiac signs and their dates. If your birthday falls within one of those date ranges, that’s your zodiac sign.
Granted, modern science has shown astrology to be an ancient fallacy, a way of connecting patterns in celestial movements to events and behaviors here on Earth. But for ancient people, such patterns were necessary given the fact that they lacked an understanding of human psychology, astronomy, and that Earth was not the center of the universe.
The concept of the zodiac originated in Babylon in the 2nd millennium BCE, and was later influenced by Hellenistic (Ancient Greek), Roman, and Egyptian culture. This resulted in a mix of traditions, where the 12 zodiac symbols were associated with the 12 Houses – different fields of experience associated with the various planets – and the four classical elements (Earth, Wind, Water and Fire).
The symbols of the zodiac. Credit: what-is-astrology.com
In essence, astrology maintains that celestial phenomena are related to human activity, so the signs are held to represent certain characteristics of behavior and personality traits. What we know today as astrology comes from the 2nd century AD, as it was formally described by Ptolemy in his work, Tetrabiblos.
This book was responsible for the spread of astrology’s as we know it across Europe and the Middle East during the time of the Roman Empire. These traditions have remained relatively unchanged for over seventeen centuries, though some alterations have been made due to the subsequent discoveries of the other planets in our Solar System.
Naturally, the birth of the modern psychology, biology and astronomy has completely discredited the notion that our personalities are determined by birth signs, the position of the stars or the planets. Given what we know today of the actual elements, the movements of the planets, and the forces that govern the universe, astrology is now known for being little more than superstition.
What’s more, the dates of the ‘star signs’ were assigned over 2,000 years ago, when the zodiac was first devised. At that time, astronomers believed that the Earth’s position was fixed in the universe, and did not understand that the Earth is subject to precession – where Earth’s rotational and orbital parameters slowly change with time. As such, the zodiac signs no longer correspond to constellations of stars that appear in night sky.
The constellations Ophiuchus, represented as a man grasping a snake. Credit: chandra.harvard.edu
And last, but certainly not least, there is the issue of the missing 13th sign, which corresponds to the constellation Ophiuchus. Over 2000 years ago, this constellation was deliberately left out, though the Sun clearly passes in front of it after passing in front of Scorpius (aka. Scorpio) and before reaching Sagittarius.
It is unclear why ancient astrologers would do this, but it is a safe bet that they wanted to divide the 360° path of the Sun into 12 equal parts. But the true boundaries that divide the constellations, as defined by the International Astronomical Union (IAU), are not exact. And Ophiuchus actually spends more time behind the Sun than its immediate neighbor (19 days compared to Scorpius’ 12).
To find out what zodiac sign you were really born under, check out this story from BBC’s iWonder. And in the meantime, here are the zodiac signs, listed in order along with what they mean, and some interesting facts associated with their respective constellations:
Aries: March 21 – April 19
The sign of Aries, which covers 0° to 30° of celestial longitude, is represented by The Ram, which is based on the Chrysomallus – the flying ram that provided the Golden Fleece in Greek mythology. Aries is associated with the First House, known traditionally as Vita (Latin for life) and in the modern context as the “House of Self”. Aries is associated with Fire, and the ruling celestial body of Aries is Mars.
The Aries constellation is also home to Teegarden’s Star, one of Sun’s closest neighbors, located approximately 12 light years away. It appears to be a red dwarf, a class of low temperature and low luminosity stars. And then there’s Alpha Areitis, which is easily spotted by the naked eye. Also known as “Hamal” – literally “head of the sheep” in Arabic – this star is located at the point where constellations angles downward to form an arc.
The constellation Aries. Credit: iau.org
For those with telescopes, several galaxies can be spotted within the Aries constellation as well. These include the spiral galaxy NGC 772 and the large 13th magnitude NGC 697 spiral galaxy. NGC 972 is another, which is faint (at magnitude 12) and part of a galaxy group. And then there’s the dwarf irregular galaxy NGC 1156, which is considered a Magellanic-type galaxy with a larger than average core.
Aries is also home to several meteor showers, such as the May Arietids. This daylight meteor shower begins between May 4th and June 6th with maximum activity happening on May 16th. The Epsilon Arietids are also a daylight occurrence, and are active between April 25th to May 27th with peak activity on May 9th. And then there are the Daytime Arietids, which occur from May 22nd to July 2nd with a maximum rate of one a minute on June 8th.
To top it off, the Aries constellation contains several stars with extrasolar planets. For example, HIP 14810, a G5 type star, is orbited by three confirmed exoplanets, all of them giant planets (all Super-Earths). HD 12661, also a G-type main sequence star, has two orbiting planets (which appear to be Super-Jupiters). And HD 20367, a G0 type star, has one orbiting gas giant that roughly the same size as Jupiter.
Taurus: April 20 – May 20
The sign of Taurus, which covers 30° to 60° of celestial longitude, is represented by The Bull – which is based on the Cretan Bull that fathered the Minotaur and was killed by Theseus. Taurus is associated with the Second House, known by the Latin name of Lucrum (wealth) and by the modern name, “House of Value”, and the element Earth. The ruling celestial body of Taurus is Venus.
The constellation Taurus. Credit: iau.org
Taurus’ brightest star, Alpha Tauri, is also known by its traditional name, Al Dabaran (which was Latinized to become Aldebaran). The name, which is Arabic, literally means “the Follower” because of the way the Taurus constellation appears to follow the Pleiades star cluster across the sky. In Latin, it was traditionally known as Stella Dominatrix, but to Medieval English astronomers, it was known as Oculus Tauri – literally the “eye of Taurus.”
There is one major annual meteor shower associated with the constellation of Taurus: the annual Taurids, which peak on or about November 5th of each year and have a duration period of about 45 days. The maximum fall rate for this meteor shower is about 10 meteors per hour, with many bright fireballs often occurring when the parent comet – Encke – has passed near perihelion.
And speaking of Pleiades (aka. Messier 45, The Seven Sisters) this cluster of stars is located perpendicular to Aldebaran in the night sky, and is visible to the unaided eye. Although it is made up of over 1000 confirmed stars, this object is identifiable by its seven particularly bright blue stars (though as many as 14 up can be seen with the naked eye depending on local observing conditions).
Gemini: May 21 – June 20
The sign Gemini covers 60° to 90° of the celestial longitude, and is represented by The Twins. These are based on the Dioscuri of Greek mythology, two mortals that were granted shared godhood after death. Gemini is part of the Third House, traditionally named Fratres (Brothers) and currently known as the House of Communications. The associated element for Geminis is Air, and the ruling celestial body is Mercury.
The constellation Gemini. Credit: iau.org
Gemini’s alpha and beta stars – aka. Castor and Pollux (“The Twins”) – are the easiest to recognize and can be spotted with the naked eye. Pollux is the brighter of the two, an orange-hued giant star of magnitude 1.2 that is 34 light-years from Earth. Pollux has an extrasolar planet revolving around it, as do two other stars in Gemini, a super-Jupiter which was confirmed in 2006.
There are two annual meteor showers associated with the constellation of Gemini. The first is the March Geminids, which peaks on or around March 22nd. The average fall rate is generally about 40 per hour (but this varies) and the meteors appear to be very slow, entering our atmosphere unhurriedly and leaving lasting trails.
The second meteor shower are the Geminids themselves, which peak on or near the date of December 14th, with activity beginning up to two weeks prior and lasting for several days. The Geminids are one of the most beautiful and mysterious showers, with a rate of about 110 per hour during a moonless night.
The Gemini constellation is also associated with Messier 35, a galactic open star cluster that is easily spotted with the naked eye. The star cluster is quite young, having formed some 100 million years ago, and is quite bright due to it having blown away most of its leftover material (i.e. nebular dust and gas) that went into the star formation process. Other open clusters in Gemini include NGC 2158, which lies directly southwest of M35 in the night sky.
The open star clusters Messier 35 and NGC 2158, photographed at La Palma, Roque de los Muchachos. Credit: estelar.de/Oliver Stein
Cancer: June 21 – July 22
Cancer, which covers 90° to 120° of celestial longitude, is represented by The Crab – or Karkinos, a giant crab from Greek mythology that harassed Hercules during his fight with the Hydra. The sign is associated with the Fourth House – Genitor (Parent) in Latin, or the House of Home and Family in modern times. In terms of the elements, Cancers are characterized by the element of Water, and the ruling celestial body of Cancer is The Moon.
Cancer’s best known star is Beta Cancri, also known by its Arab name Altarf (“the End”). This 3.5 magnitude star is located 290 light-years from Earth and is a binary star system that consists of a spectral type K4III orange giant and a magnitude 14 red dwarf. This system is also home to a confirmed exoplanet, beta Cancri b, which is a Super-Jupiter with an orbital period of over 600 days.
In terms of deep-sky objects, Cancer is best known as being the home of Messier Object 44 (aka. Praesepe, or the Beehive Cluster), an open cluster located in the center of the constellation. Located 577 light-years from Earth, it is one of the nearest open clusters to our Solar System. M44 contains about 50 stars, the brightest of which are of the sixth magnitude.
The smaller, denser open cluster of Messier Object 67 can also be found in Cancer, which is 2500 light-years from Earth and contains approximately 200 stars. And so can the famous quasar, QSO J0842+1835, which was used to measure the speed of gravity in the VLBI experiment conducted by Edward Fomalont and Sergei Kopeikin in September 2002.
The location of the Caner constellation. Credit: IAU
The active galaxy OJ 287 is also found in the Cancer constellation. Located 3.5 billion light years away from Earth, this galaxy has a central supermassive black hole that is one of the largest known (with 18 billion solar masses), and produces quasi-periodic optical outbursts. There is only one meteor shower associated with the constellation of Cancer, which is the Delta Cancrids. The peak date for this shower is on or about January 16t, and has been known to average only about 4 comets per hour (and the meteors are very swift).
Leo: July 23 – Aug. 22
Those born under the sign of Leo, which covers 120° to 150° of celestial longitude, carry the sign of The Lion – which is based on the Nemean Lion of Greek mythology, a lion that had an impenetrable hide. The sign of Leo is tied to the Fifth House, known in Latin as Nati (Children), or by its modern name, House of Pleasure. The sign of Leo is also associated with the element of Fire and the ruling celestial body of Leo is The Sun.
There are five annual meteor showers associated with the constellation Leo. The first is the Delta Leonid meteor stream, which begins between February 5th through March 19th every year. The activity peaks in late February, and the maximum amount of meteors averages around 5 per hour. The next is the Sigma Leonid meteor shower, which begins on April 17th. This is a very weak shower, with activity rates no higher than 1 to 2 per hour.
The next is the November Leonids, the largest and most dependable meteor shower associated with the Leo constellation. The peak date is November 17th, but activity occurs around 2 days on either side of the date. The radiant is near Regulus and this is the most spectacular of modern showers.
The constellation Leo. Credit: iau.org
The shower is made more spectacular by the appearance of the Temple-Tuttle comet, which adds fresh material to the stream when it is at perihelion. The last is the Leo Minorids, which peak on or about December 14th, which is believed to produce around 10 faint meteors per hour.
Leo is also home to some of the largest structures in the observable universe. This includes many bright galaxies, which includes the Leo Triplet (aka. the M60 group). This group of objects is made up of three spiral galaxies – Messier 65, Messier 66, and NGC 3628.
The Triplet is at a distance of 37 million light-years from Earth and has a somewhat distorted shape due to gravitational interactions with the other members of the Triplet, which are pulling stars away from M66. Both M65 and M66 are visible in large binoculars or small telescopes, but seeing them in all of their elongated glory requires a telescope.
In addition, it is also home to the famous objects Messier 95, Messier 96, and Messier 105. These are spiral galaxies, in the case of M95 and M96 (with M95 being a barred spiral), while Messier 105 is an elliptical galaxy which is known to have a supermassive black hole at its center. Then there is the Leo Ring (aka. Cosmic Horseshoe) a cloud of hydrogen and helium gas, that orbits two galaxies found within this constellation.
The notable gravitational lens known as the Cosmic Horseshoe is found in Leo. Credit: NASA/ESA/Hubble
Virgo: Aug. 23 – Sept. 22
The sign of Virgo, which covers 150° to 180° of celestial longitude, is represented by the The Maiden. Based on Astraea from Greek mythology, the maiden was the last immortal to abandon Earth at the end of the Silver Age, when the gods fled to Olympus. Virgo is part of the Sixth House – Valetudo (Health) in Latin, or House of Health in modern times. They are also associated with the element of Earth and the ruling celestial body of Virgo is Mercury.
The brightest star in the Virgo constellation is Spica, a binary and rotating ellipsoidal variable – which means the two stars are so close together that they are egg-shaped instead of spherical – located between 240 and 260 light years from Earth. The primary is a blue giant and a variable star of the Beta Cephei type.
The star 70 Virginis was one of the first planetary systems to have a confirmed exoplanet discovered orbiting it, which is 7.5 times the mass of Jupiter. The star Chi Virginis has one of the most massive planets ever detected, at a mass of 11.1 times that of Jupiter. The sun-like star 61 Virginis has three planets: one is a super-Earth and two are Neptune-mass planets.
The constellation Virgo. Credit: iau.org
Libra: Sept. 23 – Oct. 22
The sign of Libra covers 180° to 210° of celestial longitude. It is represented by the symbol of The Scales, which is based on the Scales of Justice held by Themis, the Greek personification of divine law and custom and the inspiration for modern depictions of Lady Justice. Libra is part of the Seventh House – Uxor (Spouse) or House of Partnership, are associated with the element of Air, and the ruling celestial body is Venus.
Two notable stars in the Libra constellation are Alpha and Beta Librae – also known as Zubenelgenubi and Zubeneschamali, which translates to “The Southern Claw” and “The Northern Claw”. Alpha Libae is a double star consisting of an A3 primary star with a slight blue tinge and a fainter type F4 companion, both of which are located approximately 77 light years from our Sun.
Beta Librae is the brighter of the two, and the brightest star in the Virgo constellation. This is a blue star of spectral type B8 (but which appears somewhat greenish) which is located roughly 160 light years from Earth. Then there’s Gamma Librae (also called Zubenelakrab, which means “the Scorpion’s Claw”) which completes the Scorpion sign. It is an orange giant of magnitude 3.9, and is located 152 light-years from Earth.
The constellation Libra. Credit: iau.org
Libra is home to the star Gliese 581, which has a planetary system consisting of at least 6 planets. Both Gliese 581 d and Gliese 581 g are considered to be some of the most promising candidates for life. Gliese 581 c is considered to be the first Earth-like exoplanet to be found within its parent star’s habitable zone. All of these exoplanets are of significance for establishing the likelihood of life outside of the Solar System.
Libra is also home to one bright globular cluster, NGC 5897. It is a fairly large and loose cluster, has an integrated magnitude of 9, and is located 40,000 light-years from Earth.
Scorpio: Oct. 23 – Nov. 21
The sign of Scorpio covers 210° to 240° of celestial longitude. Scorpio is represented by The Scorpion, which is based on Scorpius – a giant scorpion in Greek mythology sent by Gaia to kill Orion. Scorpio is part of the Eighth House – Mors (Death), known today as the House of Reincarnation – and is associated with the element of Water. Traditionally, the ruling celestial body of Scorpio was Mars, but has since become Pluto.
The Scorpius constellations includes many bright stars, the brightest being Alpha Scorpii (aka. Antares). The name literally means “rival of Mars” because of its distinct reddish hue. Other stars of note include Beta Scorpii (Acrab, or “the scorpion”), Delta Scorpii (Dschubba, or “the forehead”), Xi Scorpii (Girtab, also “the scorpion”), and Sigma and Tau Scorpii (Alniyat, “the arteries”).
Lambda Scorpii (Shaula) and Upsilon Scorpii (Lesath) – whose names both mean “sting”- mark the tip of the scorpion’s curved tail. Given their proximity to one another, Lambda Scorpii and Upsilon Scorpii are sometimes referred to as “the Cat’s Eyes”.
The constellation Scorpius. Credit: iau.org
The Scorpius constellation, due to its position within the Milky Way, contains many deep-sky objects. These include the open clusters Messier 6 (the Butterfly Cluster) and Messier 7 (the Ptolemy Cluster), the open star cluster NGC 6231 (aka. Northern Jewel Box), and the globular clusters Messier 4 and Messier 80 (NGC 6093).
The constellation is also where the Alpha Scorpiids and Omega Scorpiids meteor showers take place. The Alphas begin on or about April 16th and end around May 9th, with a peak date of most activity on or about May 3rd. The second meteor shower, the Omega (or June) Scorpiids peaks on or about June 5th of each year. The radiant for this particular shower is closer to the Ophiuchus border and the activity rate on the peak date is high – with an average of about 20 meteors per hour and many reported fireballs.
Sagittarius: Nov. 22 – Dec. 21
The sign of Sagittarius covers 240° to 270° of celestial longitude and is represented by The Archer. This symbol is based on the centaur Chiron, who according to Greek mythology mentored Achilles in the art of archery. Sagittarius is part of the Ninth House – known as Iter (Journeys) or the House of Philosophy. Sagittarius’ associated element is Fire (positive polarity), and the ruling celestial body is Jupiter.
Stars of note in the Sagittarius constellation include Alpha Sagittarii, which is also known as Alrami or Rukbat (literally “the archer’s knee”). Then there is Epsilon Sagittarii (“Kaus Australis” or “southern part of the bow”), the brightest star in the constellation – at magnitude 1.85. Beta Sagittarii, located at a position associated with the forelegs of the centaur, has the traditional name Arkab, which is Arabic for “achilles tendon.”
The Sagittarius constellation. Credit: iau.org
The second-brightest star is Sigma Sagittarii (“Nunki”), which is a B2V star at magnitude 2.08, approximately 260 light years from our Sun. Nunki is the oldest star name currently in use, having been assigned by the ancient Babylonians, and thought to represent the sacred Babylonian city of Eridu. Then there’s Gamma Sagittarii, otherwise known as Alnasl (the “arrowhead”). This is actually two star systems that share the same name, and both stars are actually discernible to the naked eye.
The Milky Way is at its densest near Sagittarius, since this is the direction in which the galactic center lies. Consequently, Sagittarius contains many star clusters and nebulae. This includes Messier 8 (the Lagoon Nebula), an emission (red) nebula located 5,000 light years from Earth which measures 140 by 60 light years.
Though it appears grey to the unaided eye, it is fairly pink when viewed through a telescope and quite bright (magnitude 3.0). The central area of the Lagoon Nebula is also known as the Hourglass Nebula, so named for its distinctive shape. Sagittarius is also home to the M17 Omega Nebula (also known as the Horseshoe or Swan Nebula).
This nebula is fairly bright (magnitude 6.0) and is located about 4890 light-years from Earth. Then there’s the Trifid Nebula (M20 or NGC 6514), an emission nebula that has reflection regions around the outside, making its exterior bluish and its interior pink. NGC 6559, a star forming region, is also associated with Sagittarius, located about 5000 light-years from Earth and showing both emission and reflection regions (blue and red).
Capricorn: Dec. 22 – Jan. 19
The sign of Capricorn spans 270° to 300° of celestial longitude and is represented by the Mountain Sea-Goat. This sign is based on Enki, the Sumerian primordial god of wisdom and waters who has the head and upper body of a mountain goat, and the lower body and tail of a fish. The sign is part of the Tenth House – Regnum (Kingdom), or The House of Social Status. Capricorns are associated with the element Earth, and the ruling body body is Saturn.
The constellation Capricornus. Credit: iau.org
The brightest star in Capricornus is Delta Capricorni, also called Deneb Algedi. Like other stars such as Denebola and Deneb, it is named for the Arabic word for “tail”, which in this case translates to “the tail of the goat’. Deneb Algedi is a eclipsing binary star with a magnitude of 2.9, and which is located 39 light-years from Earth.
Another bright star in the Capricorni constellation is Alpha Capricorni (Algedi or Geidi, Arabic for “the kid”), which is an optical double star (two stars that appear close together) – both o which are binaries. It’s primary (Alpha² Cap) is a yellow-hued giant of magnitude 3.6, located 109 light-years from Earth, while its secondary (Alpha¹ Cap) is a yellow-hued supergiant of magnitude 4.3, located 690 light-years from Earth.
Beta Capricorni is a double star known as Dabih, which comes from the Arabic phrase “the lucky stars of the slaughter” a reference to ritual sacrifices performed by ancient Arabs. Its primary is a yellow-hued giant star of magnitude 3.1, 340 light-years from Earth, while the secondary is a blue-white hued star of magnitude 6.1. Another visible star is Gamma Capricorni (aka. Nashira, “bringing good tidings”), which is a white-hued giant star of magnitude 3.7, 139 light-years from Earth.
Several galaxies and star clusters are contained within Capricornus. This includes Messier 30 (NGC 7099) a centrally-condensed globular cluster of magnitude 7.5. Located approximately 30,000 light-years from our Sun, it cannot be seen with the naked eye, but has chains of stars extending to the north that can be seen with a telescope.
The globular cluster Messier 30, imaged by the Hubble Telescope. Credit: NASA/Wikisky
And then there is the galaxy group known as HCG 87, a group of at least three galaxies located 400 million light-years from Earth. It contains a large elliptical galaxy, a face-on spiral galaxy, and an edge-on spiral galaxy. These three galaxies are interacting, as evidenced by the high amount of star formation in the face-on spiral, and the connecting stream of stars and dust between edge-on spiral and elliptical galaxy.
The constellation of Capricornus has one meteor shower associated with it. The Capricornid meteor stream peaks on or about July 30th and is active for about a week before and after, with an average fall rate is about 10 to 30 per hour.
Aquarius: Jan. 20 – Feb. 18
Aquarius, which spans 300° to 330° of celestial longitude, is represented by the Water Bearer. In ancient Greek mythology, Aquarius is Ganymede, the beautiful Phrygian youth who was snatched up by Zeus to become the cup-bearer of the Gods. Aquarius is part of the Eleventh House – Benefacta (Friendship), or House of Friendship, is associated with the element of Air. Traditionally, the ruling celestial body of Aquarius was Saturn, but has since changed to Uranus.
While Aquarius has no particularly bright stars, recent surveys have shown that there are twelve exoplanet systems within the constellation (as of 2013). Gliese 876, one of the nearest stars (15 light-years), was the first red dwarf start to be found to have a planetary system – which consists of four planets, one of which is a terrestrial Super-Earth. 91 Aquarii is an orange giant star orbited by one planet, 91 Aquarii b, a Super-Jupiter. And Gliese 849 is a red dwarf star orbited by the first known long-period Jupiter-like planet, Gliese 849 b.
The constellation Aquarius. Credit: iau.org
Aquarius is also associated with multiple Messier objects. M2 (NGC 7089) is located in Aquarius, which is an incredibly rich globular cluster located approximately 37,000 light-years from Earth. So is the four-star asterism M73 (which refers to a group of stars that appear to be related by their proximity to each other). Then there’s the small globular cluster M72, a globular cluster that lies a degree and half to the west of M73.
Aquarius is also home to several planetary nebulae. NGC 7293, also known as the Helix Nebula, is located at a distance of about 650 light years away, making it the closest planetary nebula to Earth. Then there’s the Saturn Nebula (NGC 7009) so-named because of its apparent resemblance to the planet Saturn through a telescope, with faint protrusions on either side that resemble Saturn’s rings.
There are five meteor showers associated with the constellation of Aquarius. The Southern Iota Aquarids begin around July 1st and end around September 18th, with the peak date occurring on August 6th with an hourly rate of 7-8 meteors average. The Northern Iota Aquarids occur between August 11th to September 10th, their maximum peak occurring on or about August 25th with an average of 5-10 meteors per hour.
Image of the Helix Nebula, combining from information from NASA’s Spitzer Space Telescope and the Galaxy Evolution Explorer (GALEX). Credit: NASA
The Southern Delta Aquarids begin about July 14th and end around August 18th with a maximum hourly rate of 15-20 peaking on July 29th. The Northern Delta Aquarids usually begin around July 16th, and last through September 10th. The peak date occurs on or around August 13th with a maximum fall rate of about 10 meteors per hour.
Then there is the Eta Aquarid meteor shower, which begins about April 21th and ends around May 12th. It reaches its maximum on or about May 5th with a peak fall rate of up to 20 per hour for observers in the northern hemisphere and perhaps 50 per hour for observers in the southern hemisphere. Last, there is the March Aquarids, a daylight shower that may be associated with the Northern Iota Aquarid stream.
Pisces: Feb. 19 – March 20
The sign of Pisces covers 330° to 360° of celestial longitude and is represented by the The Fish. This symbol is derived from the ichthyocentaurs – a pair of centaurian sea-gods that had the upper body of a male human, the lower front of a horse, and the tail of a fish – who aided Aphrodite when she was born from the sea. Pisces is part of the Twelfth House of Carcer (Prison), or The House of Self-Undoing, and are associated with the element of Water. The ruling celestial body of Pisces is traditionally Jupiter, but has since come to be Neptune.
The constellation Pisces. Credit: iau.org
Beta Piscium, also known as Samakah (the “Fish’s Mouth”), is a B-class hydrogen fusing dwarf star in the Pisces constellation. Located 495 light years from Earth, this star produces 750 times more than light than our own Sun and is believed to be 60 million years old. The brightest star in the constellation, Eta Piscium, is a bright class B star that is located 294 years away from our Solar System.
This star is also known by its Babylonian name, Kullat Nunu (which translates to “cord of the fish”), the Arab name Al Pherg (“pouring point of water”), and the Chinese name Yòu Gèng – which means “Official in Charge of the Pasturing“, referring to an asterism consisting of Eta Piscium and its immediate neighbors – Rho Piscium, Pi Piscium, Omicron Piscium, and 104 Piscium.
And then there’s van Maanen’s Star (aka. Van Maanen 2) a white dwarf that is located about 14 light years from our Sun, making it the third closest star of its kind to our system (after Sirius B and Procyon B). Gamma Piscium is a yellow-orange giant star located about 130 light years away, and is visible with just binoculars.
The Pisces constellationis also home to a number of deep-sky objects. These include M74, a loosely-wound spiral galaxy that lies at a distance of 30 million light years from our Sun. It has many clusters of young stars and the associated nebulae, showing extensive regions of star formation. Also, there’s CL 0024+1654, a massive galaxy cluster that is primarily made up of yellow elliptical and spiral galaxies. CL 0024+1654 lies at a distance of 3.6 billion light-years from Earth and lenses the galaxy behind it (i.e. it creates arc-shaped images of the background galaxy).
Last, there the active galaxy and radio source known as 3C 31. Located at a distance of 237 million light-years from Earth, this galaxy has a supermassive black hole at its center. In addition to being the source of its radio waves, this black hole is also responsible for creating the massive jets that extend several million light-years in both directions from its center – making them some of the largest objects in the universe.
There is one annual meteor shower associated with Pisces which peaks on or about October 7 of each year. The Piscid meteor shower has a radiant near the Aries constellation and produces an average of 15 meteors per hour which have been clocked at speeds of up to 28 kilometers per second. As always, the meteoroid stream can begin a few days earlier and end a few days later than the expected peak and success on viewing depends on dark sky conditions.
Currently, the Vernal Equinox is currently located in Pisces. In astronomy, equinox is a moment in time at which the vernal point, celestial equator, and other such elements are taken to be used in the definition of a celestial coordinate system. Due to the precession of the equinoxes, the Vernal Equinox is slowly drifting towards Aquarius.
Astrology is a tradition that has been with us for thousands of years and continues to be observed by many people and cultures around the world. Today, countless people still consult their horoscope to see what the future has in store, and many more consider their birth sign to be of special significance.
And the fact that many people still consider it to be valid is an indication that superstitious and “magical” thinking is something we have yet to completely outgrow. But this goes to show how some cultural traditions are so enduring, and how people still like to ascribe supernatural powers to the universe.
We have a complete guide to all 88 constellations here at Universe Today. Research them at your leisure, and be sure to check out more than just the “zodiac sign” ones!
We also have a comprehensive list of all the Messier Objects in the night sky.
The symbols of the eight planets, and Pluto, Credit: insightastrology.net
In our long history of staring up at the stars, human beings have assigned various qualities, names, and symbols for all the objects they have found there. Determined to find patterns in the heavens that might shed light on life here on Earth, many of these designations also ascribed (and were based on) the observable behavior of the celestial bodies.
When it came to assigning signs to the planets, astrologists and astronomers – which were entwined disciplines in the past -made sure that these particular symbols were linked to the planets’ names or their history in some way.
Mercury:
This planet is named after the Roman god who was himself the messenger of the gods, noted for his speed and swiftness. The name was assigned to this body largely because it is the planet closest to the Sun, and which therefore has the fastest rotational period. Hence, the symbol is meant to represent Mercury’s helmet and caduceus – a herald’s staff with snakes and wings intertwined.
Mercury, as imaged by the MESSENGER spacecraft, which was named after the messenger of the gods because it has the fastest orbit around the Sun. Image Credit: NASA/JHU/Carnegie Institution.
Venus:
Venus’ symbol has more than one meaning. Not only is it the sign for “female”, but it also represents the goddess Venus’ hand mirror. This representation of femininity makes sense considering Venus was the goddess of love and beauty in the Roman Pantheon. The symbol is also the chemical sign for copper; since copper was used to make mirrors in ancient times.
Earth:
Earth’s sign also has a variety of meanings, although it does not refer to a mythological god. The most popular view is that the circle with a cross in the middle represents the four main compass points. It has also been interpreted as the Globus Cruciger, an old Christian symbol for Christ’s reign on Earth.
This symbol is not just limited to Christianity though, and has been used in various culture around the world. These include, but are not limited to, Norse mythology (where it appears as the Solar or Odin’s Cross), Native American cultures (where it typically represented the four spirits of direction and the four sacred elements), the Celtic Cross, the Greek Cross, and the Egyptian Ankh.
In fact, perhaps owing to the simplicity of the design, cross-shaped incisions have made appearances as petroglyphs in European cult caves dating all the way back to the beginning of the Upper Paleolithic, and throughout prehistory to the Iron Age.
Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA
Mars:
Mars is named after the Roman god of war, owing perhaps to the planet’s reddish hue, which gives it the color of blood. For this reason, the symbol associated with Mars represents the god of wars’ shield and spear. Additionally, it is the same sign as the one used to represent “male”, and hence is associated with self-assertion, aggression, sexuality, energy, strength, ambition and impulsiveness.
Jupiter:
Jupiter’s sign, which looks like an ornate, oddly shaped “four,” also stands for a number of symbols. It has been said to represent an eagle, which was the Jovian god’s bird. Additionally, the symbol can stand for a “Z,” which is the first letter of Zeus – who was Jupiter’s Greek counterpart.
The line through the symbol is consistent with this, since it would indicate that it was an abbreviation for Zeus’ name. And last, but not least, there is the addition of the swirled line which is believed to represent a lighting bolt – which just happens to Jupiter’s (and Zeus’) weapon of choice.
Saturn:
Like Jupiter, Saturn resembles another recognizable character – this time, it’s an “h.” However, this symbol is actually supposed to represent Saturn’s scythe or sickle, because Saturn is named after the Roman god of agriculture (after the Greek god Cronus, leader of the Titans, who was also depicted as holding a scythe).
Jupiter, the largest planet in the Solar System, is appropriately named after the Roman father of the gods. Credit: NASA/ESA/A. Simon (Goddard Space Flight Center)
Uranus:
The sign for Uranus is a combination of two other signs – Mars’ sign and the symbol of the Sun – because the planet is connected to these two in mythology. Uranus represented heaven in Roman mythology, and this ancient civilization believed that the Sun’s light and Mars’ power ruled the heavens.
Neptune:
Neptune’s sign is linked to the sea god Neptune, who the planet was named after. Appropriately, the symbol represents this planet is in the shape of the sea god’s trident.
Pluto:
Although Pluto was demoted to a dwarf planet in 2006, it still retains its old symbol. Pluto’s sign is a combination of a “P” and a “L,” which are the first two letters in Pluto as well as the initials of Percival Lowell, the astronomer who discovered the planet.
A full Moon flyby, as seen from Paris, France. Credit and copyright: Sebastien Lebrigand.
Moon:
The Moon is represented by a crescent shape, which is a clear allusion to how the Moon appears in the night sky more often than not. Since the Moon is also tied to people’s perceptions, moods, and emotional make-up, the symbol has also come to represents the mind’s receptivity.
Sun:
And then there’s the Sun, which is represented by a circle with a dot in the middle. In the case of the Sun, this symbol represents the divine spirit (circle) surrounding the seed of potential, which is a direct association with ancient Sun worship and the central role the Sun gods played in their respective ancient pantheons.
Every Thanksgiving when I was home from college, at least one family member would turn to me and ask me how that astrology degree was going, or tell me about a new astrology article they read. It wasn’t that my family members really thought I was studying astrology or even believed astrology was scientific, it was just that they mixed up “astronomy” with “astrology.” In all fairness, for those who don’t follow either astrology or astronomy very closely, it might be considered an honest mistake.
So when a report from the National Science Foundation claimed a majority of young Americans believed astrology was scientific I had my doubts. But so did psychologist, Richard Landers from Old Dominion University who performed a small second study and found the report to be biased.
Since 1979, NSF surveys have asked Americans whether they view astrology — the study of how the movement of celestial bodies affects the here and now — as being scientific.
Their most recent survey showed that nearly half of all Americans (42 percent) believe astrology to be scientific. But what’s more alarming, according to the NSF, is that American understandings of science are moving in the wrong direction. It seems our golden year was in 2004, when 66 percent of Americans said astrology was not at all scientific. That number has been dropping ever since.
It should come as no surprise that those with a higher education are more willing to demote astrology entirely. In 2012, 72 percent of those with graduate degrees indicated that astrology is not scientific, compared with only 34 percent of those who didn’t graduate high school.
Shockingly, age was also related to perceptions of astrology. Younger respondents (ages 18-24) seemed to give astrology a high vote of confidence,with only 42 percent claiming that it isn’t scientific. So roughly six in every 10 young adults believe astrology is absolutely scientific.
But such dramatic conclusions are being drawn from a single question: “Is astrology scientific?” It’s based on the crucial assumption that people are correctly interpreting the word “astrology.”
Landers guessed that the survey respondents might be mixing up the term “astrology” with “astronomy.” So he performed a quick survey himself, using Amazon Mechanical Turk (MTurk) — a crowdsourcing internet marketplace. He collected 100 responses to a survey that asked three questions:
— Please define astrology in 25 words or less.
— Do you believe astrology to be scientific?
— What is your highest level of education completed?
His initial assessment — without taking into account how the respondent defined astrology — showed results very similar to the original survey provided by the NSF — approximately 30 percent found astrology to be scientific. While this percentage is less than what the NSF report found, Landers believes this is due to a user bias (MTurk users tend to be more educated and older than the average American).
But once Landers included the answer to the first question into his results, he saw a very clear trend: those who defined astrology correctly did not believe it to be scientific, while those who confused astrology with astronomy did believe it to be scientific.
Data collected from 100 participants using MTurk. Image Credit: R. Landers
Among those that correctly identified astrology, only 13.5 percent found it to be “pretty scientific.” And only one person found it to be “very scientific.” Among those that confused astrology with astronomy, the discipline was overwhelmingly seen as scientific.
“My little quick study doesn’t ‘overturn’ the NSF results” Landers told Universe Today. “It only suggests that the NSF results are probably biased to some degree.”
With such small number statistics Landers certainly didn’t prove the NSF results wrong, but he does call the study into question. Landers also noted an additional study from the European Commission which corroborated his findings.
I for one would love to see the NSF conduct a more detailed study. Including a definition of astrology in the next round of surveys would certainly bring clarification and shed light on the root of the problem.
—
Update: After posting this article, a reader informed me of a critique of Richard landers’ assessment, posted by The Washington Post’s Jim Lindgren. He conducted another follow-up study to explore the issue. In his own sample, Lindgren found that probably only one respondent out of 108 confused “astrology” with “astronomy.” He claims it’s unlikely the NSF report was biased at all.
However, the back and forth banter between experts suggests these words and their corresponding definitions do need to be clarified. Science journalists have their work cut out for them.
So you think the position of Mars in the sky at the time of your birth made you tall, dark, and handsome (or short, fair, and ugly)? Or lucky (or unlucky) in love? If you think believing in astrology is anywhere close to scientific, well, Dude, time to think again.
Pick two babies born within a minute of each other. One has two nurses and a doctor attending; the other, just a midwife. One is born in a brightly lit maternity ward in a downtown big city hospital; the other in a poorly lit room in a village 50 kilometers from the nearest big city. ‘Downtown’ is just a few meters above sea level; the village is situated on a 1000 meter high plateau. These local differences have far greater effects on the babies than Mars does. Let’s see how.
Nearly five centuries of physics have given us quite a few certainties, and among those are that the only long range forces in the universe are gravity and electromagnetism. And both of these, from Mars, are totally – and I mean totally – overwhelmed by those same forces that were produced by things near you when you were delivered. In a word, Mars can’t influence you.
Start with gravitation.
The gravitational force between you and Mars is greatest when Mars is closest to the Earth; let’s say that’s 56 million kilometers. Now Mars has a mass of 6.4 x 1023 kg, so the acceleration, here on Earth, due to Martian gravity would be 1.4 x 10-8 meters per second per second (m s-2).
How does this compare with variations in gravitational force due to adults standing nearby (everyone has a mother, so we won’t count her)?
Let’s take 60 kg as an adult’s mass, and a distance of 1 meter; that gives a gravitational acceleration of 4 x 10-9 m s-2, so just three adults nearby would have the same gravitational effect on you as Mars!
How does this compare with variations in gravitational force we know people born at the same time – but elsewhere on Earth – experienced?
Let’s take a difference in altitude of 1000 m (lots of big cities have altitudes greater than this – Mexico City, for example, is at 2240 m – and lots are close to sea level), and calculate the difference in acceleration due to the Earth’s gravity (this ignores several important factors, such as the Earth’s rotation, and local differences in g). Well, it works out as 0.003 m s-2, or about 200,000 times greater than Martian gravity!
In fact, if you were born just half a centimeter higher, you’d be influenced to the same extent, gravitationally, as by Mars!
You can be influenced, electromagnetically, in four separate ways: by a magnetic field, by an electric current, by an electric field, and by electromagnetic radiation. How powerful is Mars, electromagnetically?
There’s no electric current between Mars and Earth; the solar wind – which blows outward from the Sun (so Mars is ‘downstream’, and any electromagnetic influence carried by the solar wind would be from Earth to Mars) – is neutral, on balance, and carries no current.
The solar wind is a plasma, and any electric field there is in it will not be felt much more than a few Debye lengths’ away (basically, because electrons and ions are free to move in a plasma, they screen charges – the source of electric fields – quite effectively; the Debye length is about as far as an electric field can penetrate). Now the solar wind can be quite dynamic – meaning it can change a lot – but the Debye length in any part of it will rarely, if ever, be greater than a few tens of meters. Let’s be generous and say an electric field could be felt up to a kilometer away. But Mars never comes closer to the Earth than ~50 million km!
Well, that makes any electric field influence from Mars impossible, doesn’t it?!
While Mars does have a weak magnetic field, it has no influence on Earth, because the Earth’s own field creates a magnetosphere around us, one that screens out external magnetic fields. Besides, as Mars is downstream from us (the way the solar wind blows), and as the solar wind can carry (actually stretch) a magnetosphere only in the direction it blows, any magnetic influence would be from Earth to Mars, not Mars to Earth.
Three down, one to go.
The Earth’s atmosphere blocks all electromagnetic radiation except for that which we see by (and a bit on the UV side too), some infrared, and in the microwave and radio regions of the electromagnetic spectrum.
Mars is a very weak source of microwaves and radio waves, and even in the (radio) quietest places on Earth, electromagnetic radiation from (distant) radio stations, (distant) cellphone towers, TV satellites, airplanes overhead, etc totally, totally drowns out any Martian signals.
On a clear, moonless night, Mars may seem bright to your dark-adjusted eyes … but most likely you were born under quite bright lights, and indoors. No Martian influence here either.
So what do we have then?
Like I said, Mars can’t make you tall dark and handsome, nor can it influence your love life.
