Our understanding of the universe today is very different from the universe that astronomers knew just 100 years ago. Astronomers then had no idea how vast and empty space was, nor did they understand the tremendous evolutionary changes that had occurred in the Cosmos. The Cosmos, the Greek word for universe, is incredibly huge! Because light travels at a finite speed, 186,000 miles per second (300,000 kilometers per second) we are always looking into the past with our telescopes. Some objects are so far away that the light from them has been traveling toward us for 10 billion years. And the sky glows uniformly from photons emitted 15 billion years ago from an early epoch before any stars had formed. The Cosmos is not eternal; it began about 1 billion years ago in a burst of incredible energy,the Big Bang. This super-hot ball of energy and fundamental particles rapidly expanded and cooled, forming the protons, neutrons, and electrons found in all ordinary matter today. The hot gas eventually cooled even more, allowing the stars and galaxies to form the objects we see today with our telescopes. But these accumulations of matter occupy less than 1/10 of 1 percent of space! The Cosmos is nearly empty due to its expansion. We are part of this evolutionary history. Our Sun, our planet Earth and all life are made of the atoms composed of the protons and neutrons from the Big Bang. The Earth was cool enough so that the complex molecules of life formed and evolved over billions of years into us, you and me. We are really just another natural stage in the evolution of the Cosmos. In the description that follows we will examine how ancient astronomers interpreted the sky. We will see how the patterns of bright stars were used for story telling and cultural mythology. And finally, we will close with a look at modern astronomy. The last section of the book contains the personal names of stars assigned by the International Star Registry. This book is part of a series of star names assigned by ISR.
Pre-Historic Star Gazing
Since the beginning of human society, people have looked at the night sky and perceived patterns with the stars. The human brain seems to be genetically wired to look for patterns and regularity—even if none exist. People crane their necks, and use the night sky like a giant Connect-the-Dots game.
“Mommy, do you see that wolf up there?”
“Yes, that’s to remind us that wolves hunt at night and will carry off small children, if we are not careful!”
In this manner, a mother’s concern was made cosmically official and beyond challenge. So it was with stories about bears, serpents, scorpions, and sea monsters.
All societies have connected these stellar dots in various ways, making order out of the chaos above us. Doing so, according to psychologists, makes us feel less afraid because we recognize the repetitive patterns that return year after year. Humans have a sense of time. We have memory that goes beyond the last time we ate. We learn; i.e., develop response patterns, from past experiences and then predict outcomes when faced with similar circumstances. When there are no surprises, our lives can be tranquil and more productive. Human society likes order. It takes less thought, debate, and decision. One of the oldest indications that the sky was used to mark the passage of time comes to us from the Caves of Lascaux in southern France. Cro-Magnon artists over 15,000 years ago painted horses, antelope and bulls on the cave walls. And they also drew clusters of dots and squares recently interpreted by researchers as the phases of the Moon—a lunar calendar. Because the sky patterns are repetitive and predictable, shamans and astrologers developed elaborate fortune- telling beliefs, the precursors to religious faith systems. They kept records of sky events and unusual occurrences such as solar and lunar eclipses, “new” stars, comets, and rare conjunctions of the bright planets. They also named the bright stars. When one knows the name of a person, a relationship can be calm and non-threatening—even friendly. Naming the stars was important because then the stars became familiar friends in the night sky. We humans have a need to know our place in the Cosmos, our role in its past, present, and future. We see our- selves as a part of an organic universe. We have acted under the belief that our actions are influenced by the Cosmos and our actions influence the Cosmos in return. Hindu and Buddhist religions call this the Law of Karma, the spiritual law of cause and effect. Isaac Newton called this principle the Third Law of Motion—for every action there is an equal and opposite reaction. Ancient mariners used knowledge of the sky for navigation. They memorized the star pictures and star names. This knowledge was handed down from generation to generation and used to sail the Mediterranean Sea and Indian, and the Pacific oceans. In a very real sense the Diaspora of the human species resulted, in part, from knowledge of the night sky.
What are Constellations?
Constellations are groupings of bright stars in the night sky. The patterns, or “star pictures”, as they are called in many languages, do not change from year to year. Those near the celestial poles can be seen sometime during the night all year long; others appear and disappear depending on the seasons. The bright stars provide a permanent background map against which moving objects and unexpected visitors can be measured. The Sun, Moon, the five bright planets, the unpredictable comets and flashing meteors make up these moving objects. Short-lived bright stars know as novae occasionally appear in the sky as well.
Origin of Names Used Today
Elaborate legends grew around some of the constellations and were passed on from the wise elders to their youngsters. Perhaps the stories were written first and the heavens used as a giant easel to make drawings illustrating the tales. Humans have named these constellations after animals, mythological beasts, boats, rivers, hunters, gods and goddesses, and even craftsmen’s tools. Most of the names western cultures now use for bright stars and the constellations in the Northern Hemisphere came to us from Babylon, Egypt, Greece and Rome. The Bull, the Scorpion and the Lion are known to have been named over 6,000 years ago. The appearance of Orion and the brightest star in the sky, Sirius, rising in the early summer dawn foretold the annual flooding of the Nile. Oriental cultures have an equally elaborate system of ancient legends and star names. However we use the nomenclature used by professional astronomers, which was derived from the west.
The constellations of the Zodiac are the best known because of their use in astrological horoscopes; but there are even larger, more spectacular star pictures that fill the rest of the sky. About 200 AD, the famous Egyptian astrologer Ptolemy compiled a sky atlas of 48 constellations. Not all of the stars in the sky were assigned to constellations by ancient astrologers. As modern astronomy began to develop in Europe, more complete sky atlases were prepared. Often new constellations were invented to fill up space between better-known ones. Sometimes they were created for political reasons, to commemorate some obscure event in medieval European history. Most importantly, when European adventurers sailed around the world and viewed the sky from the southern hemisphere for the first time, many constellations were invented out of necessity to complete the jigsaw puzzle of the sky. In 1603 Johann Bayer, a German astronomer, published a major sky atlas revision named Uranometria. At the same time he introduced the system of bright-star designations still used by professional astronomers today. He took the letters of the Greek alphabet to name the stars within a constellation in order of their apparent brightness. Thus the star commonly known as Betelgeuse has the Bayer designation Alpha Orionis because it is the brightest star in the constellation Orion. Orionis is the Latin genitive, or possessive case of Orion. Eventually, astronomers changed some of the traditional boundaries, consolidated some constellations and divided a few very large ones, like Argo Navis, into manageable territories. The astronomers Jakob Bartsch and Johannes Hevelius revised and codified the constellations in 1624 and 1690. The French astronomers, for example Abbe Nicolas Louis de Lacaille, got into the act in the 18th and 19th centuries. So there was a mixture of names from different times and cultures. Finally in 1930 everyone agreed to the present boundaries of just 88 constellations. Most professional astronomers know little or nothing about the myth or origin of the constellation names. Researchers are interested in the physical nature of our universe. For them, the constellations are used only to indicate the general direction of objects in the sky. Since the stars in a particular constellation are normally at very different distances along the line of sight, there is usually no physical connection between them. This is similar to the lack of association between individuals who live in Minnesota and Moscow, although both cities start with the letter M.
The Constellations of the Zodiac and the Calendar
The Sun, Moon and the five bright planets are the most obvious of the moving objects in the sky. Like the swallows of Capistrano, the motions of these bodies are repetitive and predictable. And they all move in a narrow band in the sky about 10 degrees wide known as the ecliptic. The ecliptic is really the extension of the Sun’s equator. All of the planets revolve around the Sun in the same flat plane and in the same counter-clockwise direction as seen from the Sun’s north pole. Of all the constellations, only thirteen provide the background of the ecliptic. Twelve of the 13 are known as the zodiacal constellations. The ecliptic path is tipped 23.5 degrees with respect to the Earth’s equator. It’s really the Earth that is tipped, of course. This inclination causes the seasons. As viewed from planet Earth, the Sun stands on the equator at dawn on the first day of spring, known as the vernal equinox. On this day the Sun rises exactly at the East point on the horizon. Then the Sun climbs slowly to 23.5 degrees north of the equator on the first day of summer, the summer solstice. The Sun then reverses its course, slowly returning to the equator on the autumnal equinox when it again appears due east at sunrise. It then continues to its lowest point in the sky, 23.5 degrees south of the equator on the first day of winter or winter solstice. To pinpoint these seasonal indicators, prehistoric astronomers in many countries constructed calendar circles, such as the world-famous Stonehenge in England. Although the Sun, Moon and the planets are confined to this ecliptic path, they move at different speeds. The Moon, for example, whizzes around the ecliptic in 29½ days, while Venus, the brightest star-like object in the sky, moves back and forth with respect to the background stars every 224 days. Saturn takes nearly 30 years to complete its circuit.
The Egyptians astrologers noted that the Sun took about 365 days to “circle the sky”. They also knew that 365 was not evenly divisible by any small integers except 5. So they chose a more convenient number, 360, and divid- ed the sky into equal parts. This number can be evenly divided by many integers:—2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, and 30. In this way they could organize and divide their civil calendar into rational sections. This Egyptian civil calendar, based on this motion of the Sun around the sky, left five extra days to party at the end of the year! Notice that 7 and 11 are numbers that cannot evenly divide 360. That made them special. The ancients therefore associated greater luck with them, a belief that still influences us at the dice tables of Las Vegas. The number 13, also not on the list, developed the reputation as a bad luck symbol. The Mayan astrologers of Central America divided the year into four 91-day quarters, with only one extra party day at the end of the year. Obviously the Egyptians had more fun! Roman astrologers under Julius Caesar realized that there were really 365¼ days in the solar year, and they refined their calendar to more closely represent the solar motions. However there was still that little problem of the extra six hours per year. So in 46 BC the astronomer Sosigenes devised the plan of adding one extra day each fourth year, the leap year, to keep the Roman social calendar synchronized with the rest of the Universe. Christianity and the Western world adopted this Julian calendar, with its 12 months of differing numbers of days, until it became apparent that it needed further refining.
The Change From the Julian to the Gregorian Calendar
Over the centuries the spring equinox had been appearing about a day earlier every century, in spite of the leap year correction. By 1582 AD, it had advanced from March 21 to March 11. This worried religious authorities because it affected the dates of important celebrations—Easter, for example. Easter is the Christian feast of the Resurrection that occurred two days after the Jewish Passover. Passover is defined by the Jewish lunar calendar to be the first Sabbath after the first full Moon after the vernal equinox. So Easter is also determined by the spring equinox and the phases of the Moon. Refining the mathematical calculations used by the Church to determine Easter was one of the goals of Nicolas Copernicus (1474–1547 AD). The Church had used the observations and model of the solar system of Ptolemy from 200 AD. This model placed the Earth in the center of the Universe and uses elaborate geometry to describe and predict the motions of the Sun, Moon and planets, as they appear to move around the Earth.
Debate Over Geocentric and Heliocentric Models
To suggest that the Sun was in the center of the solar system upset Church authorities to such an extent that arrest, torture and death by burning at the stake were common consequences. Copernicus knew this, and delayed the publication of his revolutionary heliocentric theory until after he died. Galileo Galilei (1564–1642 AD.) got into trouble with Church authorities and the Jesuits during the Inquisition for publicly promoting Copernicus’s model of the solar system. Until his time the study of the stars and planets was largely an exercise in philosophy, not observation. Galileo’s development of the telescope had allowed him to substantiate the theory with observational evidence. But the religious authorities weren’t buying it. He was convicted of heresy and spent the last seven years of his life under house arrest. The Sun-centered model was gradually accepted, however, and following a recent review of his case in Rome, after 350 years his conviction was overturned and Galileo exonerated by the Church. Regardless of which astronomical model is used, both geocentric and heliocentric models had to be corrected to bring back the spring equinox from March 11 to March 21. So Pope Gregory XIII introduced a new calendar, which he named after himself, as leaders often do, in 1582. By papal decree the day after October 4 would be October 15. And each century year not divisible by 400 would add a “century day” to eliminate equinox creep. In 1900, the century day was added as June 31, as it will be in 2100, 2200 and 2300. But we missed getting the extra holiday in 2000. It is interesting to note that many countries in Eastern Europe continued to use the older Julian calendar into the 20th century. Even in Great Britain and its colonies the Gregorian calendar was not recognized until 1750! It seems that the rejection of papal authority by Henry VIII in 1530 over his controversial request for a divorce from Catherine of Aragon had calendar consequences for over 200 years. What happened when British employers were faced with ten fewer days in 1750? Were workers told to skip their vacations that year? And think of the many people who were robbed of their birthday parties.
The Zodiac and Astrology
Today we distinguish between study of astrology and the science of astronomy. Astrology is a belief or faith that somehow events on Earth are influenced by the positions of the planets. Today astronomers look disapproving- ly on astrology, calling it a pseudo-science, like fortune telling. But let’s remember that the two professions were one and the same until only in the last 200 years. The word astrology is a combination of the Greek words for star and word. In this context astrology means trying to make sense of the motions of celestial bodies, trying to find logical meaning in the sky. The world model accepted by all ancient cultures placed the Earth in the center of the universe. The heavens were the realm of the gods who exercised power over creatures on Earth. Evil powers inhabited the interior of the Earth. Even today ask a 6-year old child to point at Heaven and at Hell and see how deeply this cosmic error is imbedded in the human psyche. Faced with no understanding of the causes of earthquakes, volcanoes, hurricanes, floods, pestilence, disease, etc., mankind looked into the night sky for explanations of the catastrophes affecting him. Perhaps he could predict the future by carefully watching the signs. The Greeks, Romans, and Christian philosophers have argued the question of the existence of free will. Does man really have a choice in moral decisions? Or is he subject to powerful forces beyond his control, maybe beyond his comprehension? Are events predestined? Is fate the overwhelming determinant in the course of our lives? Some people seem to have more ‘luck’ than others. Astrology is an attempt to correlate events in our individual lives with the relative positions of the Sun, Moon, and planets. It is perhaps the oldest belief system shared by all cultures on Earth. People of many cultures around the world still believe in astrology, to varying extents. In America, after the comics, the horoscope column is the most read feature in the daily newspaper. The Chinese calendar has its own dos and don’ts depending upon whether its the year of the Snake or the year of the Dog. Modern Tibetan Buddhist astrologers carefully prepare the yearly calendar looking for days when the planets may have bad positions for certain earthly activities. On some days it is not a good idea to travel, or buy a house. If there is a lot of bad energy, the astrologers just skip that day. If June 7th is a bad day, then the calendar will have a June 6th followed by June 8th! The New Age spiritual movement of recent years has as one of its central beliefs that nothing happens by chance—it is our job to look for signs around us and adjust our actions to remain in harmony with the Universe. If something bad happens, it may be due to our ignoring the warnings.
The zodiacal constellations are the only ones of importance to western astrology. Modern western astrology is derived from the Greco-Roman belief system. The sky was divided into 12 constellation zones along the ecliptic, each 30 degrees wide. The Sun spends 30.44 days in each sign. The first sign begins with the vernal equinox. During Roman times, 2,500 years ago, the Sun entered the constellation Aries, the Ram on that date, March 21. Astrologers divide humans into 12 personality types according to the moment of their birth. Your “Sun sign” is the position of the Sun when you were born. A complete horoscope is a map of the sky showing the relative loca- tion of the Sun, Moon and all the planets at a given moment. Conjunctions (apparent closeness) and the angular relationships among the planets add individuality to your persona. According to this system of belief, the compatibility between people is largely based on their horoscopes, which are the major determinant of personalities and characteristics. Astrologers were highly regarded in ancient civilizations due to the overwhelming influence their advice had over the actions of those in power. Astrologers were often consulted for opinions on important social events. Is next Sunday the best day for crowning the new king? Should we plant the crops this week or next? Should the wedding be on Saturday or Wednesday? In principle an astrologer would be consulted for every important decision.
Precession of the Earth’s Axis
Since the Earth wobbles a bit, like a spinning top, the direction of its poles slowly changes. One complete wobble takes 25,800 years. This causes the positions of the equinoxes and solstices to shift slowly against the back- ground of the constellations, and is known as the precession of the equinoxes. The vernal equinox moves from constellation to constellation every 2,150 years. Today the Sun is in the constellation Pisces on March 21, one whole constellation backwards from Aries. Soon the vernal equinox will be in Aquarius. Read more about the Age of Aquarius below in our description of that constellation. Modern astrologers ignore this shift in the background screen of constellations. They maintain that it is the relative positions of the planets that influence us, not the stars themselves. The permanent star fields behind the planets are just a convenient reference. Today there are, in fact, 13 constellations that the ecliptic passes through. In 1930 the International Union of Astronomers, an organization of professional astronomers, revised and codified the names and boundaries of the constellations. The boundaries of Sagittarius were officially changed, with part of its former territory being placed in the constellation Ophiuchus. Astrologers ignore this fact, using the original 12 signs of equal length as the map upon which they plot the relationships of influential bodies—Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn.
The Twelve Constellations of the Astrologers’ Zodiac
These 12 constellations are to be found on the Egyptian astrologer Ptolemy’s list of 48 constellations. They are organized by the period the Sun was in front of them in Ptolemy’s time. The traits, aspects and careers listed are those generally accepted by astrologers.
Aries, The Ram. March 21–April 19
Trait: assertive, creative
Positive aspects: creative, brave, direct, pioneering, energetic
Negative aspects: selfish, pugnacious, and impatient
Careers: artist, composer, writer, rock star
Aries was sent by the god Hermes to save the two children of the King of Thessaly from their cruel stepmother. Was killed in the effort. Then the leader of the Argonauts, Jason, using his ship Argo, recovered the Golden Fleece from this mythical ram.
Taurus, The Bull. April 20–May 20
Trait: possessive, permanent
Positive aspects: practical, reliable, ethical in business and moral issues
Negative aspects: self-indulgent, boring, stubborn, opinionated
Careers: bankers, judges
The Greek myth talks about how Zeus, the father of all the gods, fell in love with Europa, the princess of Phoenicia. He disguised himself as a majestic white bull to attract her attention. Once she was on his back he carried her across the sea to the island of Crete. Western civilization developed around cattle husbandry. The cow was a source of milk, meat, clothing, shoes, and field labor, so it was reasonable to see this grouping as a giant bull. Taurus is just east of Orion who some see as a bullfighter or toreador. It is known that the constellation was defined long before the Greeks, but not as a bull. To the Egyptians, this was their god Osiris, while the Chinese saw it as the “White Tiger” or “Great Bridge.” The red giant star Aldebaran marks his eye. Pleiades, the famous star group also called the Seven Sisters, is located within the boundaries of the constellation Taurus.
Gemini, The Twins. May 21–June 21
Trait: communicative, loquacious
Positive aspects: intellectual, talkative, youthful, busy, energetic Negative aspects: moody, changeable, gossipy, two-faced Career: TV presenter, communicator
Castor and Pollux were fraternal twin brothers (different fathers, same mother). The brothers were inseparable in life and excelled in the martial arts. Castor was a horseman as well. These Greek heroes were among the men who went with Jason on his voyages on the ship Argo. When Castor died, Pollux went to Zeus to ask that both of them be placed in the sky together.
Cancer, The Crab. June 22–July 22
Trait: understanding, obedient
Positive aspects: protective, sensitive, tenacious, cautious, resourceful
Negative aspects: over-protective, self-pitying, unforgiving
Career: doctor, security guard
Crabs are respected inhabitants of the ocean floor. The myth associated with Cancer involves a heroic struggle between Hercules and Hydra, the water snake. Hera sent little Cancer to nip at Hercules’s feet to distract him during the fight. Hercules crushed Cancer but at least he was placed in the sky as a reward for his heroic but pitiful effort. This constellation contains no bright stars; but has the beautiful large family of stars M44, known as the Beehive cluster.
Leo, The Lion. July 23–August 22
Positive aspects: powerful, generous, creative, showy, dramatic
Negative aspects: bully, pompous, conceited, stubborn
Career: entrepreneur, CEO, politician
The lion is the most feared predator in the savannas of Africa and elsewhere. Lions were prominent in both Egyptian and Hindu astrology. Tribal chiefs often adorn themselves in lion skins as a symbol of their authority. In the Greek myth, Hercules strangled the mighty Leo as one of his twelve labors and then used his skin, which couldn’t be penetrated by stone or metal, for his tunic. In the Middle Ages Christians associated Leo with the biblical story of Daniel in the lion’s den.
Virgo, The Virgin. August 23–September 22
Positive aspects: meticulous, organized, discriminating, caring Negative aspects: workaholic, hypercritical, finicky, a worrier Careers: scientist, office assistant, customs inspector
Virgo was identified as the goddess of the harvest. In some cultures she is also the goddess of justice, unswayed by emotional arguments. The Sun is descending to the autumnal equinox at the end of Virgo’s month. At the same time the full Moon moves higher in the sky and provides evening light for the harvest. In countries where grapes were grown and harvested, it was traditional to have vir- gins stomp the grapes for the first crush in wine making.
Libra, The Balance Scales. September 23–October 23
Trait: harmony, balance
Positive aspects: charming, idealist, diplomatic, romantic Negative aspects: indecisive, oscillating, frivolous Careers: travel agent, flight attendant, sellers, marketers
The date of equal day-equal night occurs on September 23, the first day of Libra. In some traditions Libra is not a person; but rather, the scales of justice held in the hands of Virgo. Libra also refers to the marketplace, where the fruits of the harvest were sold or traded.
Scorpius, The Scorpion. October 24–November 21
Positive aspects: purposeful, subtle, persistent, resourceful Negative aspects: obstinate, secretive, jealous, crafty Careers: policeman
The scorpion was sent by Apollo to protect his sister’s chastity from the advances of Orion. After many battles, Scorpius finally killed the great hunter. They were then placed in opposite parts of the sky so that they are never up at the same time. The stars in Scorpius actually look like a scorpion with its curved tail and stinger to the south. Astrologers refer to it as Scorpio. Scorpions become more active in the fall, eating insects that are abundant because of the fall harvest. The new constellation boundaries approved by astronomers in 1930 placed part of Scorpius’s previous property in the constellation Ophiuchus.
Sagittarius, The Archer. November 22–December 21
Positive aspects: optimistic, jovial, dependable, freedom-loving Negative aspects: tactless, capricious, extreme, overly optimistic Career: lawyer, real estate agent
Sagittarius is the celestial archer and is depicted as a feared centaur, the half-man half-horse creature of Greek mythology. The center of our galaxy, the Milky Way, lies in the direction of Sagittarius. In its boundaries are numerous star clus- ter and emission nebulae familiar to amateur astronomers worldwide. The arrow in his bow is pointed at Scorpius to keep him at bay.
Capricornus, The Mountain Goat. December 22–January 19
Trait: calculating, cautious
Positive aspects: patient, loyal, disciplined, headstrong Negative aspects: miserly, rigid, merciless, dominating Career: engineer, government worker
Capricornus has been recognized since Babylonian times as a goat. Often he is shown with a fish tail, perhaps relating to a manifestation of the Greek god Pan. While fleeing the god Typhon, Pan jumped into the Nile River. The part that was below water took the form of a fish, while his torso, above water, remained that of a goat. Pan is the god of revelry, music, and fine wine.
Aquarius, The Water Carrier. January 20–February 18
Trait: humane, charitable
Positive aspects: friendly, idealistic, intellectual, wise Negative aspects: tactless, eccentric, iconoclastic Career: charity worker
The constellation is often drawn as a man pouring a jar of water. The Water Carrier is symbolic of the bearer of life-giving liquids, having altruistic concern for others. Aquarius represents harmony and understanding instead of selfishness and greed. The vernal equinox point will move into Aquarius in the near future. The precession of the Earth’s axis takes about 25,800 years to complete its circle. So the vernal equinox remains in a constellation for about 2000 years. Some astrologers ascribe the constellation’s characteristics to that “age”. Since Roman times we have been living in the Age of Pisces, which has negative characteristics. Soon we will begin the Age of Aquarius with its more positive social aspects. A popular rock musical of the 1970’s Hair, which embodied the hopes of that generation for a world of harmony, under- standing, and peace on Earth. There is some discrepancy among astrologers as to when the Age of Aquarius actually begins. Some say it began in 1997. Others calculate that the year 2080 will be the beginning. Most agree that we are in the transition period between the two Ages right now. Because of the boundaries adjustment in 1930, the Sun won’t enter the modern Aquarius until 2800 AD.
Pisces, The Fishes. February 19–March 20
Positive aspects: compassionate, emotional, receptive, fun
Negative aspects: weak-willed, indecisive, secretive, vague, careless
Career: an actor or actress
Pisces, two fish tied together, has been around since Babylonian times. Ancient Greeks told the story of Venus and her son Cupid being frightened by the monster Typhon while on the banks of the Euphrates River. They escaped with their lives by jumping into the river and taking on the form of fish. Pisces has been associated with malignant influences. The astrological calendar describes the emblems of this constellation as indicative of violence and death—really bad vibes! The Sun has been in Pisces on the vernal equinox for about 2000 years. This “Age of Pisces” has seen the most destructive wars in human history, as well as the development of weapons of mass destruction.
The Other Constellations Visible In The North
To appreciate and understand the spatial relationships of the constellations, look at the star chart on page…first we list the constellations visible in the northern hemisphere, which carry nearly all of the mythological back- ground. We list them in alphabetical order so, like words in the dictionary, they are easy to find. The origin of the name is listed.
Andromeda, The Chained Princess (In Ptolemy’s list of 200 AD)
Daughter of Cepheus and Cassiopeia, she was chained to a rock by the ocean as a sacrifice to the sea monster Cetus. She got into this mess after her mother boasted how beautiful she was. Neptune was angered and decided to torture the girl and her parents. Just as the sea monster was about to grab her, Perseus stepped in and killed him. Cepheus allowed Andromeda and Perseus to be married. In Andromeda is the nearest large spiral galaxy like our own Milky Way. The Andromeda Galaxy is visible under dark sky conditions as a faint hazy object. With a good pair of binoculars one can make out its elongated spiral shape. The light entering your eyes left that galaxy about two million years ago!
Aquila, The Eagle (In Ptolemy’s list of 200 AD)
Aquila is the eagle who carried thunderbolts for Zeus. It lies in a gorgeous sec- tion of the Milky Way. The brightest star in Aquila is Altair, which is about 16 light years away, making it a near neighbor. Altair forms one point of the Summer Triangle together with Deneb in Cygnus, and Vega in Lyra.
Auriga, The Charioteer (In Ptolemy’s list of 200 AD)
Some stories say that Auriga invented the chariot, or at least the harnesses for attaching two horses to a lightweight war wagon. It was the charioteer’s job to manage and maneuver the chariot during battle while the warrior clubbed and sliced his way through the enemy. The chariot was the ancient forerunner of the tank. Remember Ben Hur? Another myth maintains that Auriga’s father, who was crippled, invented this chariot, the original wheel chair, so that his son could move him about more easily.
Bootes, The Bear Driver (In Ptolemy’s list of 200 AD)
Bootes is depicted as a hunter carrying a large club in his right hand and the leash to his hunting dogs, Canes Venatici, in the left hand. It is not clear whether Bootes is hunting the bears of the north, Ursa Major and Ursa Minor, just scaring them away, or herding them around the North Star. This large constellation has the bright star Arcturus at its center. To find Bootes in the June sky, extend the arc of the handle of the Big Dipper (Ursa Major) southward. The first bright yellow-white star is Arcturus.
Camelopardalis, The Giraffe (In Hevelius’s list of 1690)
Named by Plancius, this constellation has no stars brighter than 4th magnitude. From modern over-lighted cities none of the stars are visible. The giraffe occupies the space between the constellations Auriga and Perseus and the North Pole star Polaris. When you have the opportunity to view the sky under dark conditions, you will find dozens of stars in this constellation.
Canes Venatici, The Hunting Dogs (In Hevelius’s list of 1690)
Hunting dogs were highly prized by the ancients. They were not just retrievers, but trackers and sometimes attack dogs. Their skills and loyalty were admired. These two dogs are found close to the handle of the Dipper in Ursa Major. They are the leashed hounds of Bootes, and bear no relation to Orion’s dogs, Canis Major and Canis Minor. Hevelius invented this minor constellation in 1687.
Canis Major, The Greater Dog (In Ptolemy’s list of 200 AD)
Canis Major is one of Orion’s two hunting dogs. He sits at the feet of his mas- ter. The brightest star in this constellation is Sirius, often called the Dog Star. It is also the brightest star in the sky being only about 10 light years away. The Egyptians watched for the early morning rising of Sirius and Orion to forecast the flooding of the Nile River.
Canis Minor, The Lesser Dog (In Ptolemy’s list of 200 AD)
Ancient cultures really loved their dogs! There are no domestic cat constellations. Should we conclude that dogs are better than cats? This small constellation is the second of Orion’s dogs. It contains the bright star Procyon. Linking the brightest stars of Orion, Taurus, Auriga, Gemini, Canis Minor and Canis Major makes a large hexagon in the winter sky.
Cassiopeia, The Queen (In Ptolemy’s list of 200 AD)
The familiar W or M, depending of the time of year, this constellation can be seen all year from northern middle latitudes. Her royal family surrounds her. Her husband Cepheus is on her left, her son-in-law Perseus is on the right, and her daughter Andromeda is just beneath her.
Centaurus, The Centaur (In Ptolemy’s list of 200 AD)
The Centaur is the mythical half-horse, half-human monster that embodied the strength and speed of a horse and the intelligence of a human. This centaur is said to be Chiron, who was very wise, and tutored Hercules and Jason. Unfortunately, Hercules wounded him by accident, and he begged to be put out of his misery. Historically humans developed horse drawn wagons and chariots before attempting to ride on the backs of horses. In battle the hands were used to hold shields and spears. Fighters couldn’t hang on or ride bareback and still be effective soldiers. Centaurs didn’t have that problem. Eventually we humans invented the technology to stick to the backs of horses—the stirrup (circa 600 AD) changed the nature of cavalry and the history of the western world.
Cepheus, The King (In Ptolemy’s list of 200 AD)
He is Cassiopeia’s husband and Andromeda’s father. He is depicted as being dressed in royal robes with a scepter in his hands. When Cassiopeia boasted that she was more beautiful than the water nymphs, she brought down the wrath of Neptune on her country. An oracle told Cepheus he could save his people if he would sacrifice his daughter, Andromeda, to the monster. Cepheus sadly chained Andromeda to a rock along the shore to await her fate. When Perseus offered to save Andromeda if he could then marry her, Cepheus agreed. In this way, Cepheus saved both his people and his daughter.
Cetus, The Sea Monster, Or Whale (In Ptolemy’s list of 200 AD)
This is an important player in the story of Perseus who rescued the lovely Andromeda, daughter of Cepheus and Cassiopeia. Cetus was the sea monster that just missed getting Andromeda for dinner. Whales were feared and largely misunderstood by ancient cultures. Because sailors and fishermen ventured out in such small boats, any encounter with a whale was an awesome experience. Cetus is also identified with the whale that swallowed Jonah in the Biblical story.
Coma Berenices, Berenice’s Hair (By Tycho Brahe, about 1590)
This cluster of faint stars represents Berenice’s hair. She was a beautiful Egyptian princess who offered to Venus to cut off her long flowing hair if her brother, the pharaoh, would return from his battle with the Syrians alive. Well, he did.
Corona Borealis, The Northern Crown (In Ptolemy’s list of 200 AD)
This almost full circle of stars represents a crown of reward given to Ariadne, thedaughter of Minos the second king of Crete. She had saved the life of Theseus, the future king of Athens in his fight against the Minotaurs. Theseus promised to marry Ariadne and take her away from Crete. But things didn’t work out, and he never married her. After her suicide, some say that Theseus asked that the crown be placed in the sky to remind him of his shameful behavior. It was the least he could do.
Corvus, The Crow (In Ptolemy’s list of 200 AD)
This small constellation looks like a trapezoid. Crows and ravens are clever birds. In some cultures they are seen as signs or omens of bad luck. But they are birds that have adapted to the growth of the human population and are known as resourceful scavengers.
Crater, The Cup (In Ptolemy’s list of 200 AD)
This small constellation represents the drinking goblets used in festivals associated with Bacchus, Apollo, Hercules and others. But sometimes it was associated with the large Hydra grouping. But sometimes it was associated with the large Hydra grouping.
Cygnus, The Swan (In Ptolemy’s list of 200 AD)
Cygnus is depicted as a swan flying, its wings oustreached and is sometimes called the Northern Cross. Its brightest star is Deneb, one of the three stars of the Summer Triangle. Swans are considered especially beautiful, elegant birds. Their dignity and grace are celebrated in many cultures.
Delphinus, The Dolphin (In Ptolemy’s list of 200 AD)
This small compact constellation looks like a little kite. Like whales, dolphins are very intelligent aquatic mammals. There are many stories of ship- wrecked mariners being saved by dolphins. Only recently a fisherman in the North Sea was saved from sharks by dolphins that rammed the sharks, driving them away from the fisherman until help arrived.
Draco, The Dragon (In Ptolemy’s list of 200 AD)
The dragon winds back and forth around 90 degrees of the sky near the North Pole. Some pictures show Draco being restrained by the foot of Hercules immediately to the south. The brightest star in Draco, Thuban, was the North Star four millennia ago. But due to the precession of the Earth’s axis, it now points toward Polaris.
Equuleus, The Foal Or Small Horse (In Ptolemy’s list of 200 AD)
This is a small constellation without bright stars just to the west of Pegasus, the winged horse. Some cultures associate the two horses as mother and foal.
Eridanus, The River (In Ptolemy’s list of 200 AD)
Eridanus represents a river in Greek mythology. The river begins near the bright star Rigel, Orion’s knee, and continues over 40 degrees to the west under Cetus. The river Eridanus is not only the sixth largest of the constellations, it is also the longest in the sky, continuing into the southern sky and ending with the bright star Achernar above the Small Cloud of Magellan. So only half of this constellation is invisible from Europe and North America.
Hercules, The Champion (In Ptolemy’s list of 200 AD)
Hercules was the greatest hero of mythology. He accomplished so many amaz- ing tasks that some suspect he was given credit for other warriors’ feats as well as his own. He killed Leo and clothed himself in the lion’s indestructible skin. He destroyed Hydra, the water snake with a hundred hissing heads. He killed the flesh eating birds that had terrorized Arcadia. He conquered and pillaged Troy. He accidentally crushed little Cancer. And he did all that before Tuesday!
Hydra, The Water Serpent (In Ptolemy’s list of 200 AD)
Hydra is a monster with a hundred serpentine heads so frightening it caused most people to die straight away. And if that didn’t work, his poisonous breath could do you in. Hercules killed him on Monday. Hydra, the largest of all the constellations, is another long one that rambles more than 90 degrees through the sky. It used to be even bigger, but was split into four more convenient parts—Sextans, Crater, Corvus and a new, slimmed- down Hydra.
Lacerta, The Lizard (In Hevelius’s list of 1690)
A little constellation, which was created to fill a small vacuum between Cepheus and Pegasus, fairly near the Milky Way. There are no bright stars and there is relatively no myth associated with the common lizard. This is a modern constellation, so sorry no mythology. The history of naming tells us, however, that several astronomers named the area in honor of their favorite king. But the king is dead; long live the lizard!
Leo Minor, The Lion Cub (In Hevelius’s list of 1690)
Hevelius named this area north of Leo in 1690. It incorporates a few stars in previously unclaimed territory. He settled on the name of Leo Minor because the stars’ proximity to the great grouping known as Leo. This happened long before the birth of Disney’s cub Simba, the prince who grew to be the Lion King.
Lepus, The Hare (In Ptolemy’s list of 200 AD)
The constellation of the hare, or jack rabbit lies just under Orion and to the west of his hunting dog, Canis Major. Tradition has it that Orion loved to hunt rab- bits and he continues hunting the Hare around the celestial circle.
Lupus, The Wolf (In Ptolemy’s list of 200 AD)
It is natural that the wolf would be a feared beast among sheep-herding folk. So the myth of Lupus is not for the weak-of-heart. To make a long, horrid tale short, the cruel king Lycaon sacrificed children on the altar of Zeus. When the god found out, he transformed him into the wolf, Lupus, and placed him in the sky near Centaurus who makes sure the wolf stays in his place.
Lynx, The Cat (In Hevelius’s list of 1690)
Hevelius named this narrow constellation of nondescript stars after the Lynx, a large cat found in the forests of Europe. He said only those with cats eyes could spot it. Perhaps its spots reminded the astronomer of a star cluster. This myste- rious and fascinating feline was once widespread, but now has almost entirely disappeared from the European continent. Several countries have adopted meas- ures for its reintroduction, and this extraordinary cat is gradually reappearing.
Lyra, The Harp (In Ptolemy’s list of 200 AD)
The lyre, a type of harp, was a musical instrument highly regarded for its near magical power to soothe the troubled mind and soul. Angels play harps. And so did Orpheus, son of the god Apollo, so sweetly, it is said that trees and flow- ers followed him, wild animals and birds came to listen, and rivers slowed to hear his music. This constellation contains Vega, one of the brightest stars in the sky, and a point of the Summer Triangle (along with Deneb and Altair). Because of the precession of the Earth’s North Pole, in about 12,000 years Vega will replace Polaris as the North Star.
Monoceros, The Unicorn (In Hevelius’s list of 1690)
Monoceros is a scattering of faint stars near the celestial equator between Canis Major and Canis Minor. It was named by Plancius, who may have had in mind the Indian Rhinoceros. The unicorn, on the other hand, is a fabulous mythical creature described as a horse with a spiral horn of gold growing from its fore- head. Even though it is very shy and rarely seen by mortals, the unicorn can defend itself with that horn. It is considered very lucky to see a Unicorn, which is reportedly visible only to those who search and trust. Monoceros boasts having two of the most massive stars yet discovered. The two blue-giants are estimated to be some 55 times the size of the Sun, and revolve around each other. Together they are known as Plaskett’s Star. The pair is violently unstable and brightens unex- pectedly from time to time, giving astronomers a thrill.
Ophiuchus, The Serpent Holder (In Ptolemy’s list of 200 AD)
In Greek mythology Ophiuchus is always associated with the first physician, Aesculapius, son of Apollo. He learned the art of healing and restoring life from Chiron, the Centaur. One of his remedies relied upon extracted snake venom, and he holds the nearby constellation Serpens, on his arm. Ophiuchus has been in fact the “thirteenth constellation” of the zodiac, since 1930, when the constellation bound- aries approved by astronomers, sliced off a chunk of Scorpius’s boundaries and added it to Ophiuchus. The Sun actually spends the first two weeks of December in front of the serpent holder.
Orion, The Hunter (In Ptolemy’s list of 200 AD)
Perhaps the most widely recognized star pattern in the sky is Orion. This giant hunter stands in front of Taurus, like a matador. Four bright stars, among them famous Betelgeuse, enclose the row of three inclined stars known as Orion’s Belt. He bears a sword on his belt and carries a lion skin and a huge club. His two faithful dogs are by his side. Another of his prey, Lepus the Hare, is at his feet. Now if you want to read a gripping story, find some of the ancient stories about Orion, one of the most universal mythological characters. You will find love, thrills, magic healing, bravery, death and pathos. Son of the sea god Neptune, he was handsome and strong and in love first with Merope, one of the Seven Sisters. Later, the beautiful Artemis, goddess of the Moon, also a keen hunter, took his fancy. Finally he was killed by the lowly Scorpion. With binoculars you can see a hazy patch below the belt stars called the Great Orion Nebula. We know today that it contains hundreds of new stars just formed from the hydrogen gas clouds illuminated by the bright surrounding stars. Some stars are less than 3,000 years old, mere infants! Photos of star birth and protoplanetary sys- tems transmitted from the Hubble Space Telescope are among the most dramatic and revealing of any space photos ever taken.
Pegasus, The Winged Horse (In Ptolemy’s list of 200 AD)
Pegasus can be easily identified as a large square next to Andromeda in the autumn sky. Actually one of the stars forming the square is assigned to Andromeda. Let’s say the two share the star. But the recurring appearance of this winged horse on the stage of Greek mythology is so much more colorful than the nickname of The Big Square. Pegasus is yet another example of the flights of fancy that Greek mythology could take. Pegasus is said to be the son of Neptune, who sprang to life from the blood of Medusa when Perseus cut off her head. Pegasus carried the warrior Bellerophon to battle against the evil Chimaera. When he really needed an extra boost in speed, he could supercharge using those big wings on his back. Pegasus was enshrined in the night sky as the bearer of Zeus’s lightening bolts.
Perseus, The Hero (In Ptolemy’s list of 200 AD)
Perseus set out to bring back the head of Medusa, one of the three snake-haired monsters of old. To equip him for his dangerous journey Pluto loaned him his helmet of invisibility (an ancient cloaking device), Minerva lent him a very shiny shield to blind opponents, and Mercury lent him the famous winged shoes and a diamond sword. With equipment like that he couldn’t lose. On his way back with the ugly head, Perseus rescued his future wife Andromeda, who was chained to a rock.
Sagitta, The Arrow (In Ptolemy’s list of 200 AD)
The smallest of all constellations, it could be the emblem of Diane and Apollo, better known as Cupid’s Arrow. Arrows were the common missiles of love as well as war in many myths. Sagitta lies in the summer skies near the Milky Way.
Scutum, The Shield (In Hevelius’s list of 1690)
This grouping was called Scutum Sobiescianmum, by Hevelius in 1690, who wanted to honor King Sobieski of Poland. The shield was supposed to represent King Sobieski’s Coat-of-Arms. Mercifully, the name was later shortened. The stars making up Scutum are not very bright. The constellation is in the middle of the Milky Way between Sagittarius and Aquila. At a much greater distance than the foreground stars, but in this same direction, is one of the spiral arms of our galaxy, known as the Scutum Arm.
Serpens, The Snake (In Ptolemy’s list of 200 AD)
This constellation is named after the snake Ophiuchus charmed, and from which he extracted medicinal venom. Serpens is another long constellation, extending away from Ophiuchus on both sides. Unique among constellations, Serpens is composed of two separate areas of the sky. The western side is also known as Serpens Caput, the snake’s head. The eastern side is sometimes called Serpens Cauda, or snake’s tail. To this day, the symbol of the medical profession is the caduceus, which is a winged staff with serpents twined around it. It is from Serpens that the symbol arose.
Sextans, The Sextant (In Hevelius’s list of 1690)
The sextant, or the similar astrolabe, is the star-sighting device used by astrologers to measure the positions of stars. The device was refined in the 15th and 16th centuries for use by navigators at sea. This constellation of faint stars was created by the German astronomer Hevelius in 1687 AD for the device which served him so well in his stellar measurements.
Triangulum, The Triangle (In Ptolemy’s list of 200 AD)
A small constellation of three stars making a triangle just south of Andromeda. In ancient times it was referred to the Delta, the capital letter “D” in the Greek alphabet. It was known to some Greeks as the Nile delta, and to others as the island of Sicily. During Christian times it was sometimes associated with the Trinity, or alternatively with the three-pointed miter hats worn by bishops in the Church.
Ursa Major, The Big Bear Or The Big Dipper (In Ptolemy’s list of 200 AD)
Ursa Major is the best-known constellation in the Northern Hemisphere. Many cultures assigned these stars to the figure of a giant bear. Its seven bright stars are also a physical clustering of stars of common origin. This constellation is circumpolar, meaning it is visible every night of the year slowly circling around the North Star Polaris. Its orientation can be used to tell the time at night. Many cultures see a figure of a water dipper with a long handle. African- American slaves had folk songs about following the “drinking gourd” at night to travel north to freedom. The two stars on the end of the cup are called the pointer stars, used to locate Polaris. The two stars on the handle side of the cup point south toward the heart of the Lion, the bright star Regulus. The curved handle itself points to the bright star Arcturus in Bootes. If that curve is extended farther it reaches Spica, the bright star in Virgo.
Ursa Minor, The Lesser Bear Or The Little Dipper (In Ptolemy’s list of 200 AD)
This group is right next to Ursa Major, and is easily remembered by relating the two as either the big and little bears, or the big and little dippers. Also a collec- tion of seven circumpolar stars, the Little Dipper is even closer to the pole. The last star in its handle is in fact the star Polaris that lies less than a degree from the true polar axis of the Earth’s rotation. Astronomers use Ursa Minor a test of sky darkness. There is still too much light pollution if you cannot see all seven stars of the Little Dipper clearly. In most large urban areas with their overuse of street and security lights, the only star visible is often just Polaris itself—and this only with the help of the brighter point- er stars of the Big Dipper.
Vulpecula, The Fox (In Hevelius’s list of 1690)
This is another of the “nouveau” constellations added by the German astronomer Hevelius to his sky atlas. The original name is Vulpecula cum Anser, the Fox and the Goose. It is located next to Cygnus in the summer Milky Way. Perhaps Hevelius meant the Fox with the Swan. Both birds constantly had to be on the lookout for preda- tory foxes.
Southern Hemisphere Constellations
The constellations listed below are best seen from the Southern Hemisphere since they are below the horizon from latitudes north of 30 degrees. Most of the bright star constellations in the south are located in the southern Milky Way. Argentines and Australians enjoy the full view of the heart of the Milky Way during the longest nights of their winter. There were several important players in the naming of the southern constellations during the Renaissance. Petrus Placius was a Dutch astronomer, cartographer and theologian. When the first Dutch expedition set out to explore the East Indies in 1595, he hired the ship’s pilot, Pieter Dirkszoorn Keyser, to make observations and fill in the blank areas around the South Celestial Pole—sort of a moonlighting job. Keyser didn’t make it back home, dying in Java, but his catalog of 135 stars was completed and delivered to Placius by his assistant Frederick de Houtman. These early navigators named about ten constellations after exotic birds, reptiles and other animals they had seen on their trip to the Southern seas. Placius drew them on a globe in 1598, and Johann Bayer incor- porated the constellation names in his Uranometria in 1603. The rest is history, as they say. Abbe Nicolas Louis de Lacaille observed and named many of the Southern Hemisphere stars and constellations during an extended stay in South Africa during 1750–1754. He made his observations from the most southerly spot he could get to—the Cape of Good Hope and, amazingly, he did this with a tiny telescope, measuring only one centimeter in diameter. Lacaille was quite a technophile, memorializing about a dozen tools of the day, most- ly recent inventions. Many of his names, however, were long and cumbersome. Thankfully, they were shortened to fit better on a sky chart. Only a few have any attached mythology, since most of this region of the sky is not visible from Greece or Egypt.
Antlia, The Air Pump
(In Lacaille’s list of 1752)
This is a small grouping of stars just north of Vela. Originally named Antlia Pneumatica, it honored the latest in mechanical technology, the air pump invented by Robert Boyle. There is no mythology here.
Apus, The Bird Of Paradise
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) This constellation was named after a tropical bird first encountered by Dutch navigators in Papua New Guinea, who called it Apus Indicus. The birds’ skins were first brought to Europe in 1522 by survivors of Magellan’s expe- dition to circumnavigate the world. Apus lies very close to the south celestial pole and is a small circumpolar con- stellation seen all year from the Southern Hemisphere.
Ara, The Altar
(In Ptolemy’s list of 200 AD)
Located south of the stinger of Scorpius, this small group depicts the altar that was erected by the Olympians to give thanks for their victory over the Titans.
Caelum, The Chisel
(In Lacaille’s list of 1752)
Named Caela Sculptoris after the tool used by sculptors and stonemasons, this faint star grouping lies between
Columba and the southern extent of Eridanus.
Carina, The Keel
(Part of the old Argo Navis, in the IAU list of 1930)
The Greeks named a huge area of the southern sky Argo Navis, tying it to the story of Jason and the ship of his Argonauts. This crown jewel of the spring equatorial skies was unceremoniously dismantled into four parts by practical astronomers—Carina, the keel; Puppis, the ship’s stern; Pyxis, the compass and Vela, the sail. Canopus (Alpha Carinae), the second brightest star in the sky, marks the rudder. Interestingly, Canopus is the only star named in classic times after a historic figure—the pilot of the fleet that sailed the Greek ships to destruction at Troy. In this direction we are looking along another spiral arm of the Milky Way. Carina contains many interesting objects. The best known is the “star” Eta Carinae. It is an unstable super massive star, about 100 times the mass of the Sun that is shedding it gaseous outer layers. There is a huge cloud of glowing gas that hides our view of the star itself. In the last century Eta Carinae was much brighter than it is today. Because the star is unstable, everyone is waiting for it to go supernova. If it does we will know it. It is only 4,000 light-years away. Nothing this big has exploded so relatively nearby. Some scientists predict a huge flux of lethal X- and Gamma radiation may strike the Earth. Stay tuned!
Chamaeleon, The Chameleon (Named by Dutch navigators Keyser and Houtman on their chart of 1597. In
Bayer’s list of 1603)
The Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman found an unusual family of lizards. These animals had the startling ability to effect a camaflage by changing their colors to match their backgrounds. They were so taken with this strange new reptile that they named a part of the sky for it. The astronomer Johann Bayer approved, and included it in his list, drawing it following the description of the early south sea explorers. The Chameleon is a faint constellation near the South Pole.
Circinus, The Draftman’s Compass
(In Lacaille’s list of 1752)
The compass is a tool used by surveyors to measure distances, and draftsmen to draw circles. It is next to anoth- er tool of the same trades, Norma, the level. This faint constellation lies close to Alpha and Beta Centauri, two of the nearest stars to the Sun and very bright southern Milky Way objects.
Columba, Noah’s Dove (In Royer’s list of 1679)
This constellation, first called Columba Noachi, was added by Plancius to honor the homing pigeon or dove that Noah released to find land after the Flood. When the rain stopped, Noah released the pigeon several times until it finally returned with an olive twig from new growth on dry land. The dove is also associated with nearby parts of Argo Navis, which Plancius saw as Noah’s Arc, with some seeing it as leading the ship ever westward.
Corona Australis, The Southern Crown (In Ptolemy’s list of 200 AD)
Just as we have a northern crown, so too there is a southern crown. Visible just south of Sagittarius, this crown is named after the olive branch garlands worn by heroes and famous politicians in Greece and Rome.
Crux, The Southern Cross (In Royer’s list of 1679)
This smallest of all constellations makes up in fame what it lacks in size. Crux has bright stars in an easily rec- ognized pattern, making it the best known of the southern groupings. It is incorporated into the flags of several southern countries: Brazil, Australia, and New Zealand to name a few. The entire constellation cannot be seen north of latitude +25 degrees. The Greeks included it as part of Centaurus, but several 16th century explorers viewed it as a distinct group. The two stars that make the upright post of the cross define a line that points toward the South Pole. Another line from Sirius through Canopus (Alpha Carinae), the second brightest star in the sky, defines a second line that intersects the aforementioned Crux line at about the South Pole. There is no bright star comparable to the north- ern Polaris at the South Pole. So southern mariners and navigators such as the Polynesians had to develop a more sophisticated knowledge of the sky that northerners. Crux contains another interesting feature. Australian aborigines and Brazilian Amazon Indians had a distinct name for a round black patch of sky with no stars at all! We call that feature The Coal Sack. It is obvious to the naked eye because it lies right in the middle of the Milky Way. We know today, largely from radio telescopes, that this black patch is really a cold dense cloud of hydrogen gas that blocks our view of the stars behind it. It is locat- ed relatively nearby so there are few stars in front of it.
Dorado, The Golden Swordfish
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) Dorado is supposed to represent a fish called Pompanos, a large, iridescent fish. Hawaiians know it as Mahi- Mahi. It is sometimes called a Dolphin fish. It also has been depicted as a swordfish. The Spanish name for the large tropical swordfish is in fact Dorado, which is considered a trophy prize by sports fisherman. For astronomers, Dorado is memorable because it con- tains half of the Large Magellanic Cloud (LMC). The LMC and the Small Magellanic Cloud are distinct star sys- tems, small irregular galaxies that are in orbit around the Milky Way. In 1987 a giant star in the region of the Tarantula Nebula in the LMC exploded as a supernova. It is the bright- est visible supernova in 383 years! It provided unprecedented data to astrophysicists, validating theories of cos- mic explosions and nucleosynthesis.
Fornax , The Furnace Or Kiln (In Lacaille’s list of 1752)
A small southern grouping of nondescript stars was named Fornax Chemica, the chemical or laboratory furnace. Tradition has that it honors Antoine Lavoisier inventor of the furnace and one of the pioneers of modern chem- istry, who was guillotined in the French Revolution in 1794. Its stars were previously part of the constellation Eridanus.
Grus, The Crane
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) Grus is a modern grouping, but it is worth mentioning that the crane was a symbol of office of the astronomer in ancient Egypt, perhaps because of its high flight. Also called Phoenicopterus (Flamingo) in the past, its stars were formerly included in Piscis Austrinus.
Horologium, The Pendulum Clock (Named by Dutch navigators Keyser and Houtman on their chart of
1597. In Lacaille’s list of 1752)
This is another of the tools of Lacaille. He named it Horologium Oscillitorium, or pendulum clock, in honor of the Dutch physicist Christian Huygens who developed the mechanism for pendulum clocks a century earlier. Huygens had also resolved the rings of Saturn with a telescope.
Hydrus, The Little Water Snake
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) This triangle of stars lies between the Large and Small Magellanic Cloud near the south celestial pole. It was apparently created as a companion to Hydra, the large female water snake in the northern sky, known since Greek times.
Indus, The American Indian
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) This is a depiction of an American native holding arrows in both hands. Perhaps the constellation is named after the native peoples of Patagonia and Terra del Fuego, regions which many navigators would have passed on their way to the South Seas. Upon encountering the natives of the new world, Christopher Columbus mistakenly thought he had landed in the East Indies and called the tribes, Indians. Columbus made several trips to the New World; but apparently never realized that the Indies were still 6,000 miles farther west. Later Italian explorers, like Amerigo Vespucci, eventually proved that the new lands were really distinct continents. That’s why they are called the Americas and not the Columbuses.
Mensa, Table Mountain
(In Lacaille’s list of 1752) Named by Lacaille Mons Mensa, or Table Mountain, after the location at which he set up his small 1-cm telescope near Cape Town, South Africa. The stars are not bright; but the constellation includes about half of the Large Magellanic Cloud (LMC), a nearby satellite galaxy of the Milky Way. The other half of the LMC is in Dorado.
Microscopium, The Microscope
(In Lacaille’s list of 1752)
This is another of the scientific instruments enshrined in the sky by Lacaille. The microscope, invented in 1590 by a Dutch spectacle maker, allowed scientists to examine the world of the Very Small. More than just a magnifying glass, the microscope reveals the fine structure of nature around us.
Musca, The Fly
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. Renamed by Lacaille on his list of
These stars were called Apis Australis by Dutch navigators and listed as the Bee (Apus) by the German astronomer Bayer. Lacaille substituted the southern Fly (Musca Australis) for the same stars. This is not an example of miscommunication, rather national rivalries of old. <
Norma, The Measuring Square
(In Lacaille’s list of 1752)
Just as we have the drawing compass and triangle, so too we have the draughtsman’s square right beside it.. Lacaille called it Norma et Regula, or level and square.
Octans, The Octant
(In Lacaille’s list of 1752)
The octant was a device for measuring the altitude of a star above the horizon, and thus, one’s latitude on the Earth. This tool was invented by John Hadley in 1730 to be used aboard ships at sea as a navigation device. It was superseded by the sextant which is also memorialized in the sky.
Pavo, The Peacock
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603)
This is a large constellation near the South Pole. Perhaps the navigators had in mind the myth of the Golden Fleece, since a peacock does appear in it. After the successful voyage of the Argo, its builder, Argus, was trans- formed into a beautiful peacock, so Pavo has his place in the heavens near to his ship (or at least the pieces of it) in the Southern sky.
Phoenix, The Symbol Of Reincarnation
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) The Phoenix is part of classical mythology. Many ancient cultures believed that life and history occurred in cycles. The Phoenix was a mythical bird of incredible beauty typifying reincarnation. After living for 500 years the bird built a funeral pyre of twigs from incense bushes and cedar. He then lit the fire, dying in the flames. But from the ashes arose a reborn Phoenix, free from the encumbrances of the past.
Pictor, The Painter
(In Lacaille’s list of 1752)
Lacaille’s original name was Equuleus Pictoris, the painter’s easel (horse, as in sawhorse).
Piscis Austrinus, The Southern Fish
(In Ptolemy’s list of 200 AD)
This fish is thought to be the parent of the larger Pisces in the north. Tradition has it that Piscis is drinking from the water pouring out of Aquarius’s urn above it. It is distinguished by the bright star, Fomalhaut, Arabic for fish mouth.
Puppis, The Stern
(Part of the old Argo Navis, in the IAU list of 1930)
Formed from the break-up of the old Argo Navis, this is the stern of the ship, the ‘poop’ deck. The radio source known as Puppis A is the remnant of a supernova from 4,000 years ago.
Pyxis, The Compass
(In Lacaille’s list of 1752, part of the old Argo Navis) This is one of the new constellations fathered by the breakup of Argo Navis. It represents the ship’s magnetic compass. Ancient mariners did not have compasses. The navigational uses of the compass were brought back to Europe from China by Marco Polo in the 13th century. Oh well, so much for historical accuracy!
Reticulum, The Crosshairs
(In Lacaille’s list of 1752) Named after the cross hairs, or reticule, in the eyepiece of a telescope.
Sculptor, The Sculptor (In Lacaille’s list of 1752)
Originally named L’Atelier du Sculptor, the sculptor’s workshop. The constellation is poorly placed. The sculptor’s chisel, Caelum, is not close by.
Telescopium, The Telescope (In Lacaille’s list of 1752)
This unremarkable constellation, first called Tubus Telescopium, is a poor tribute to such an important instru- ment. The telescope has to be ranked as the most revolutionary instrument of all time. Its use by Galileo caused all sorts of problems for theologians, and Galileo himself. As telescopes became larger, the discoveries multiplied. In the last century the reflecting telescope has grown to 10 meters (400 inches) in diameter. The decade of the 1990’s saw the fantastic pictures and data from the Hubble Space Telescope. The impact on astronomy and cos- mology of the HST has been equal or greater than Galileo’s first instrument.
Triangulum Australe, The Southern Triangle
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) This triangle is nearly equilateral and has no mythology attached to it.
Tucana, The Toucan
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) Named after the family of fruit-eating birds with an unbelievably large brightly-colored bill found in Brazil and tropical rainforests in the Americas. This constellation contains within its boundaries the Small Magellanic Cloud and perhaps the most beautiful globular cluster in the sky, 47 Tucanae.
Vela, The Sail
(Part of the old Argo Navis, in the IAU list of 1930) This ragged circle of stars represents the fully opened sail of the old Argo Navis, billowing as it catches the wind. It has the modern distinction of having the second recognized optical pulsar.
Volans, The Flying Fish
(Named by Dutch navigators Keyser and Houtman on their chart of 1597. In Bayer’s list of 1603) Originally named Piscis Volans after the tropical fish that can jump out of the water and sail in the air for sever- al meters before diving back under. Presumably the Dutch navigators saw schools of these fish in the south seas just as they were racking their brains for a zippy name of a newly-created pattern in the sky. Like the dove, Columba, it is associated with the ship Argo Navis. Off the coast of western Mexico, sports fishermen try to catch the flying fish as bait for the really big ones, the swordfish, Dorado. Appropriately Volans is right next to Dorado in the southern sky.
The Development of the Science of Astronomy
We can divide the development of the science of astronomy into two historical periods; a Classical and a Modern. The Classical period began with Isaac Newton and the publishing of his book Philosophiae Naturalis Principia Mathematica in 1686. The Modern period began with Albert Einstein’s seminal paper on Special Relativity in 1905.
The Grandfathers of Astronomy
Marking the beginning of modern astronomy with Isaac Newton is not meant to depreciate the contributions of earlier scientists. Newton himself reflected that his work would not have been possible without the help of his precursors. “I stood upon the shoulders of giants….”, he said. Some early astronomers had great insight. Eratosthenes (276–194 BC) measured correctly the circumference of the Earth. Yes, we have known the Earth was a round globe for some time! Aristarchos Of Samos (310–230 BC) proposed that the Sun was the center of the universe and that the Earth and planets revolved around it. Aristotle argued against this model because there was no back-and-forth motion of the stars detected. The argu- ment, a good one, was that if the Earth moved in a circle around the Sun, then the stars would display parallactic motion. This is like looking at a distant object first with one eye and then the other. The object appears to move back and forth with respect to the far horizon. No one guessed how far away the stars are. Stellar parallaxes were not detected until the 19th century. Aristarchos determined the distance to the Moon using trigonometry. He got the right answer, too! He made a stab at the distance to the Sun by measuring the angle between it and the Moon at First and Third Quarter phas- es. But without a telescope and an accurate clock, this is a very hard measurement to obtain. His finding was that the Sun was at least 20 times farther away than the Moon and therefore at least 20 times larger as well. The real answer is that the Sun is 400 times farther away. But science is not about being right; it’s about performing exper- iments and honestly reporting the results. If they are wrong, some other scientists will improve upon the meas- urements and report what they find. Copernicus (1473–1543) revisited the work of Aristarchos and also proposed the heliocentric model of the solar system. He backed up his theory with hard numbers, derived by applying geometry and mathematics to the best available visual data of the motions of the planets. Tycho Brahe (1546–1601) lost his nose in a duel over ‘honor’ or some woman. But no matter. Astronomy takes eyes, not noses. He constructed new sighting instruments and proceeded to record accurate stellar and planetary positions of over 1,000 stars. In 1572 he saw a new bright star appear. That object is known as Tycho’s superno- va. In 1577 he tracked a comet across the sky and showed that it had to be much farther away than the Moon. Before this most people thought that comets were phenomena within the Earth’s atmosphere. Kepler (1571–1630) was a mathematician and an astrologer. He was a strange mystical character who developed the three laws of planetary motion. Kepler used Brahe’s data, particularly the motion of the planet Mars, to derive his theory. Galileo (1564–1642) did experiments in the physics of motion and built and applied the telescope to celestial observations. He discovered the craters on the Moon, the lunar-like phases of Venus, spots on the Sun, the motions of the four brightest satellites around Jupiter (still called the Galilean moons), and some say the rings of Saturn. He was arrested for heresy because he published his observations in support of the Copernican heliocentric model. He narrowly avoided being burned at the stake!
ISAAC NEWTON (1642–1727) was a brilliant introvert whose insight into both astronomy and mathematics changed the course of human history. He solved long-standing problems in physics and astronomy by inventing calculus. For example:
The three laws of motion
Law of Universal Gravitation
Planetary orbits—revised Kepler’s laws
Precession of the Earth
The non-spherical shape of the Earth
The orbits of artificial satellites around the Earth
Perhaps the most important was his Law of Gravity. This is the force that holds the Cosmos together. Newton’s mathematics showed that if the positions and velocities of every object in the universe were known, then every future state of the universe could be calculated. Now that’s scary! Newton believed that for every Effect there must be a Cause. A consequence of his theory was to impose absolute fatalism upon the Cosmos, and by implication, on the human species as well. Nothing happens by chance. Newton’s Principia was actually a compendium of problems he had worked on for more than 20 years. He pub- lished his work largely at the urging of the Astronomer Royal, Sir Edmund Halley. Newton was able to show Halley that the comet that now bears Halley’s name was a repetitive visitor to the inner solar system with a peri- od of about 76 years. Because of the mathematical tools developed by Newton, theories and discoveries in physics and astronomy mushroomed. The planets Uranus, Neptune, and Pluto were discovered by applying gravitational theory. Newton built the first reflecting telescope, the basic optical design still used in the giant 10-meter mirror telescopes today. The world model inspired by Newton was an infinite universe moving and evolving in absolute time according to the forces of gravity. The universe had no beginning and no end. Time was infinite in extent, as well. Newton had spent a great part of his life doing alchemy. Alchemists thought that by mixing the correct acids and chemicals that any element could be transmuted into another, such as lead into gold. It turned out to be a lit- tle more complicated. Chemical processes only rearrange the outer electrons in atoms. In the 19th century sci- entists discovered the existence of atoms and organized that knowledge around the Periodic Table of Mendeleev. Not until the 20th century discoveries of the nature of the atomic nucleus did transmutation becomes possible— and then only at the expense of high energy. The last part of the Classical Period saw the development of electromagnetic theory by scientists like Oersted, Faraday, and James Clark Maxwell. Electrical charge and current flow seems at first sight to be a different phe- nomenon from magnetism. But the linkage between the two was discovered and finally reduced to a mathemat- ical theory—Maxwell’s Four Equations. The ability to generate and transmit electricity was an immediate practical application. Steam engines were replaced by electric motors in the factories. Edison invented the electric light bulb. The theory also predicted the existence of electromagnetic waves of energy that travelled at a rapid but finite speed—186,000 miles (300,000 km) per second. This was the same as the finite speed of light determined by astronomers from observations. Finally we had stumbled onto the nature of light! The theory predicted the existence of other forms of electromagnetic radiation from the shortest gamma rays to the longest radio waves. The full spectrum is now used to investigate our Cosmos.
The Modern Period
There were some mathematical and philosophical conflicts between Newtonian physics and Maxwellian elec- tromagnetic theory. Scientists don’t like discrepancies. If there is even one exception to a theory, then the theory is simply wrong, or at least incomplete. A revised or different theory evolves from new experimental tests. Since the Earth moves in its orbit around the Sun at some 30 km per second, it should be possible to see a change in the speed of light between the direction of motion and the opposite direction. If light travels at the speed X in an unmoving laboratory, then in the direction of orbital motion light should travel at X + 30 km per second. In the direction away from the orbital motion light should travel at X -30 km per second. Like walking in a moving train, one travels faster walking toward the front of the train and slower walking toward the back. Logical? Yes, but when two American scientists built a device to test this prediction, they found no difference in any direction. Michelson and Morley reported that they had nothing but negative results—nothing, zip, nada. It was the most important null experiment of the 19th century. Why didn’t light obey the laws of (Newtonian) physics? The mathematician and physicist who solved the puzzle was Albert Einstein (1879–1955). While working as an unknown Swiss patent clerk he published a visionary solution known as the Special Theory of Relativity. It was really quite simple. The discrepancies between Maxwell and Newton were due to our definition of Time. Time was not absolute; but relative to, and dependent upon, the relative velocities of two events. Simply put, nothing can travel faster than the speed of light. The speed of light, c, is a fundamental constant in the universe around us. Deal with it. One of the predictions of the theory was that a rapidly moving clock appears to run more slow- ly as seen by an observer not moving with it. Very non-intuitive! But wait, it gets better. Suppose you have two cosmonauts on the Earth who are twins. Let one cosmonaut stay on Earth and the other travels off to a star 10 light years away at the speed of light. He explores around that star for a year, and then returns to Earth, again traveling at the speed of light. The two cosmonauts are reunited upon his return to Earth. Amazingly they discover that the twin that went traveling, 21 years previously, is only one year older than when he left. The grounded twin, however, aged 21 years! Einstein must have had a lot of idle time at the patent office because he also published papers about the photo- electric effect (he got the Nobel prize for this one), how Brownian motion validated the theory of atoms, and the equivalence between matter and energy—the now-famous E=mc2 . People noticed. In 1913 Einstein got a real job in Berlin commensurate with his talents. War broke out a year later, Einstein continued to expand on his theories. In 1916 Einstein published his most radical theory, the Theory of General Relativity. Because of the difficult math, most scientists didn’t understand it. Einstein proposed that gravity, Newtonian gravity, was an illusion. Planets moved in their closed orbits because the Sun’s mass curved the space around it. This distortion of Space- Time bent the otherwise straight paths of the planets into closed ellipses. One of the predictions of the General Theory was that light itself would be bent by the same distortion of Space-Time. Many thought he had overdosed on math. Einstein’s theory, in spite of its complexity, made predictions that could be tested observationally. A British team of astronomers set out to see if the bending of light near the Sun could be observed during a total solar eclipse in 1919. When the team analyzed the data, they reported they had detected Einstein’s Gravitational Lens effect! The whole story is remarkable given the fact that Einstein was a German scientist and on the loosing side in WW I, just ended in 1918. This one experiment made Einstein an instant world celebrity. He had discovered a funda- mental property of the Cosmos that would affect theory in physics and astronomy from then on.
The Size and Contents of the Universe
Einstein’s theoretical work attracted attention, but it took decades of detailed work by astronomers to verify it, and fully comprehend the magnitude of its implications. Some built bigger and better telescopes with which to search the skies. Others gathered fundamental knowledge about the birth and death of stars, their lifetimes, and the nuclear processes that provide the energy of stars. Understanding these nuclear processes eventually led to the development of the Atomic and Hydrogen Bombs in 1944 and 1948. Well, no science is totally pure. In 1914 an American astronomer at the Flagstaff Observatory in Arizona, Vesto Slipher, published a survey of bright galaxies showing that their spectral lines indicated the vast majority were moving away from us. This was mysterious because at that time astronomers believed that galaxies, or nebulae as they were known, were small- ish collections of gas and stars—perhaps new solar systems in formation. After returning from the army in WW I, Edwin Hubble (1889–1953) began using the largest telescope in the world, the 100-inch atop Mt. Wilson, to study the distances to galaxies. He started with the biggest and brightest, the Andromeda Nebula. By carefully examining photographs taken at different times he saw the brightening and dimming of variable stars known as Cepheid Variables. Bingo! The Andromeda Nebula was really the Andromeda Galaxy located more that a million light years away. It was not inside our Milky Way at all. The Milky Way was only about 100,000 light years across, from edge to edge. Andromeda was a distant and independent galaxy! Hubble extended his study to as many more galaxies as his 100-inch (2.5 meter) telescope could reach. By 1929 it was obvious that he needed a bigger telescope. George E. Hale, another astronomer at Mt. Wilson and Caltech, obtained a grant from the Rockefeller Foundation to build a 200-inch telescope and place it at Mt. Palomar near San Diego, at that time a much darker site than any in the Los Angeles area.
The Universe—Huge and Still Growing
Hubble had determined the distances to dozens of galaxies. Using those distances and the velocity data from spectral lines, he derived the Hubble Law of Recession—galaxies appear to be racing away from us in proportion to their cosmic distance. The universe was expanding. The universe was also much bigger than anyone had suspected—hundreds of millions, perhaps billions of light years in extent. Slowly came the realization that we do not see the universe as it exists today! The light that we see from distant galaxies left those sources millions and billions of years ago. The sky is a giant window into the past. Instead of a three-dimensional universe, we must also include the fourth dimension, Time, in the under- standing of our place in the Cosmos. When Einstein met Hubble in 1929, he was very enthusiastic about Hubble’s observations. “That’s what I’ve been telling you,” Einstein basically said. He tried to explain that General Relativity math predicted that the uni- verse was unstable and therefore must either expand or contract. Hubble really didn’t understand what Einstein was talking about. He was a skilled observer, not a theoretician. Einstein had developed the theory in 1916 when astronomers did not know of the expansion. The universe looked stable and unchanging. To keep it that way Einstein had added a new repulsion force to his equations to counter the pervasive attraction of gravity. When Einstein found out in 1929 that the observations showed an expanding universe, he changed his theory to accommodate Hubble’s data.
Radio And Space Astronomy
After WW II many of the scientists involved in the development of Radar and radio communication technology turned their antennas skyward. Radio technology and the development of the digital computer have gone hand in hand. In 1962 the digital radio receiver was developed along with dozens of improvements in low noise ampli- fiers. Today we have radio telescopes that take observations over the entire spectrum, from submillimeter to meter wavelengths. Those data are used to study objects that are invisible to us, such as large clouds of gas and dust. The astronomical data from these instruments complements optical observations. In the decades since 1960 we have launched into space scores of astronomical satellites and space probes. Some have taken photographs of distant planets, asteroids and comets. Others have scanned the sky in the high-energy wavelengths that can’t be observed from the ground. The result is that we now have maps of the sky showing X-ray sources, the ultraviolet and the near and far infrared. And this is in addition to the very fine resolution visible light photos taken by the appropriately named Hubble Space Telescope. With these additional tools astronomers have detected and mapped the Cosmic Microwave Background radiation that comes to us from events nearly 14 billion years ago! We have found stars made of pure neutrons that rotate 1,000 times a second and emit radio wave pulses as they spin. We have discovered Black Holes in the centers of the majority of spiral galaxies. And we have realized that most of the stuff in the universe is dark matter of an as-yet unknown nature.
Using Newton’s law of gravity, theoreticians as early as 1783 had constructed a mathematical model of a body so massive that the escape velocity from its surface exceeds the speed of light. Because of this, the object cannot give off anything, even light. Such a body would be extremely compact and the matter inside it impossibly dense. But the physics of super dense bodies attracted no attention until Einstein’s General Relativity theory was pub- lished in 1916. General Relativity is a redefinition of gravity, and the math is complex. One of the first solutions to Einstein’s equations was made by the German physicist, Swartzschild. His solution described the physical characteristics of a massive body, later to become known as the Black Hole. An American astrophysicist, also became interested in the subject. The father of the atom bomb, J. Robert Oppenheimer, showed in 1939 that matter would fall into a singularity, a dimensionless point in the center of a Black Hole. No known nuclear forces could resist the pres- sure. The first indication that Black Holes might be real came from X-ray observations by a satellite telescope in the late 1960’s. Here we saw a binary star—one normal star and one invisible companion—in a cosmic dance. The invisible Black Hole is tearing off material from the normal star. As the matter falls into the Black Hole, it emits huge quantities of X-rays. After the Hubble Space Telescope was launched in 1990, its cameras and spectrographs detected the rapid motion of stars near the center of many galaxies. It turns out that Black Holes are common mass concentrations in the centers of most galaxies. We detect them by the tremendous gravitation force they exert on stars and gas in their immediate neighborhoods. Science fiction writers and movie producers have had a field day with Black Holes. They portray these objects as huge vacuum cleaners sucking in everything around them. Another image is that a Black Hole is a window into another dimension or, perhaps, another universe. In reality the matter collected into the Black Hole stays right there. It doesn’t disappear from our universe at all. The gravitational effects of the Black Hole just keep growing and growing and growing.
Astronomy Today and Tomorrow
Our knowledge of the Cosmos is extensive but far from complete. We have a theory of the origin of the universe that is consistent with nearly all observations. The Big Bang theory is detailed and incor- porates not only astronomical data but also high-energy particle physics and atomic theories. Simply put, the Cosmos had a beginning; it is not eternal. It came into existence 15 billion years ago and has been expanding and cooling off ever since. Ordinary matter, like the stars and us, is really only a minor fraction of the matter-energy stuff that the universe contains. Some say that ordinary matter is just 5 percent of the universe. Another 25 percent is some sort of Dark Matter; and the biggest com- ponent is called Dark Energy and is 70 percent of the Cosmic mix. This is hard to fathom. The Cosmos is still expanding and seems to be expanding faster today than it did 10 billion years ago! But, the data are still few, so this picture may change. The Hubble Law of Recession is no longer interpreted as distant galaxies actually moving away from us at near the speed of light. Instead, the redshifts we see are really the result of cosmic expansion, the stretching out of the universe in all directions. The universe itself has grown during the billions of years it has taken the light from distant galaxies to reach us. Light waves themselves are stretched out as a consequence. Eventually, using new and improved telescopes in space and on the ground, we will collect a more complete inventory of the things in the universe. We will build larger optical and radio telescopes. We will send more instruments into space. And we will construct neutrino and gravity wave telescopes. This will certainly bring startling discoveries as well as refinements of established theories. Astronomy is a dynamic and fascinating science.
Possible Life on Other Planets
In our solar system we have found forms of life only on planet Earth. Mars may have rudimentary life forms according to some astrobiologists, since a meteorite from its surface was found to have suspicious signs of fossils. On Europa, one of Jupiter’s moons, a giant ocean containing some aquatic life may be present under its ice cover- ing. But nowhere else in our system of planets does there seem to be life today. “Intelligent” life may have only developed on Earth, and it is us. When one examines the billions of Sun-like stars in our Milky Way we find that many have planetary systems. Over 80 planets have been detected around nearby stars as of the date of this writing. But do any of them harbor intelligent life forms like us, or are we really alone? We have the technology today to send and receive radio mes- sages as far away as 100 light years. Two important consequences may result if we ever discover intelligent life out there. First of all, these friendly extraterrestrials might be willing to share their knowledge
and technology with us. Why is this important? We certainly have problems before the human race on this pl be ways to solve our con self-destruction. There co miracle cures to our diseases. Secondly, we know th lifetime of our middle aged is finite. Changes will occur the future that will make t Earth a hostile environme for our species. There will be long-term global warm- ing as the Sun ages and heats up. But long before that occurs we humans will face self-generated prob- lems of over population, limited food production, air and water pollution, an possibly mass extinction d to a collision with a st asteroid or comet. Right n all of our eggs are in one b We will either become ex have to find a new planet o elsewhere to live on. Frierestrials may have faced the same problem in their past.