NIGHT SKY - Revised by Jim Colyer, October 26, 2009
NIGHT SKY
I joined the Barnard-Seyfert Astronomy club in Nashville. It is Barnard with two "a"s and Seyfert with two "e"s. The group met at the Adventure Science Center. I was looking for dark sky sites. It interested me that BSAS met an hour down Natchez Trace, far from city lights.
Eagle-eye E. E. Barnard (1857-1923) was born in Nashville. He was a great observer and discovered the first Jovian moon since Galileo. He was a professor at the University of Chicago and photographed the Milky Way at Yerkes Observatory.
Carl Seyfert (1911-1960) came to Vanderbilt in 1946. He was influential in building Dyer Observatory. He died in a car wreck in Nashville.
July 17, 2008, I attended a meeting of BSAS at the Science Center. The club president gave a presentation showing constellations and the location of Messier objects. There was discussion about star parties, when and where they should be held. The gal who operated the planetarium showed the night sky, pointing to Saturn near Regulus in Leo.
I looked forward to the Messier Marathon. They are usually held in the second half of March. The object is to observe as many of Charles Messier's 110 objects as possible.
History
It was a long road from interpreting events in the sky as the whims of gods and goddesses to explaining them as the interaction of natural causes. The sun, moon and planets are part of nature just as mountains, forests and seas are. Ancient Greeks made inroads into science. Aristarchus (310 BC - 230 BC) knew that the earth and other planets circled the sun. He was 18 centuries ahead of Copernicus and his 1543 book, "On the Revolutions of the Heavenly Spheres." Hipparchus devised the star magnitude scale of six classes which we still use.
In astronomy, things are often not what they seem. There are apparent motions, apparent magnitudes and apparent diameters. Our senses say that the sun rises in the morning and sets at night. We know it is not so. The earth is rotating. We are the ones moving. Moreover, we may think that Venus is brighter than the stars because it appears so when in reality this nearby planet reflects light from our own sun while the stars are suns trillions of miles away emitting their own electromagnetic radiation. Finally, we hold our thumbs up and cover the moon. Its apparent diameter hardly seems an inch. We know this is not the case as the astronauts who walked on the moon have told us. Our sensory perceptions evolved on earth to ensure our survival and capacity to function in the immediate surroundings. Knowledge of the earth's place in the solar system and that system's place in the Milky Way has come slowly over many centuries through the collaborative efforts of our greatest minds.
Earth
The five major circles of latitude are, from north to south, the arctic circle, Tropic of Cancer, equator, Tropic of Capricorn and antarctic circle. I am a Capricorn and since I was in Australia, I can remember that the Tropic of Capricorn runs through Australia. The Tropic of Cancer runs by the southern tip of Florida. The area between the Tropics of Cancer and Capricorn is referred to as "the tropics." The word comes from the Greek "tropos," meaning "turn," because the sun appears to turn in the sky and move in the other direction after it is overhead at noon at these points. The apparent northerly and southerly movements of the sun during the course of a year is caused by the 23 1/2 degree tilt of the earth's axis.
The hottest days come after the first day of summer, and the coldest days come after the first day of winter because it takes time for the earth to heat up and cool down.
The earth rotates 1,000 miles an hour. It revolves 66,000 miles an hour around the sun. Rotation accounts for day and night. Revolution accounts for the seasons.
It is easy to see why the ancients thought the stars rose nightly in the east and set in the west. It is an illusion given by our spinning planet.
It is also easy to see why they thought the sun went around the earth. It is the earth in its orbit around the sun that causes the stars to rise four minuters earlier each night.
Earth is called the water planet. 70% is covered by water. The four oceans are: Atlantic, Pacific, Indian and Arctic. 10% of the land is covered by ice.
Life began in the oceans, and our bodies are 75% water. Land animals need water to survive. Plants came onto the land 400 million years ago. They give off oxygen, making animal life possible.
Sun
We take the sun for granted in modern society. It is the source of the earth's energy. Without it, life on our planet would cease to exist. Earlier civilizations knew its importance. They worshipped the sun. People in high latitudes such as Scandinavians appreciate its annual return.
The sun is a star. It is one of 200 billion stars in the Milky Way galaxy. It only seems different from other stars because it is close. We circle it. It is yellow and a mere 93 million miles away. Other stars appear as points of light because they are trillions of miles from us.
The sun does not rise and set. The spinning earth makes it appear to. The apparent path of the sun is called the ecliptic because it is where eclipses take place. It is in the center of the zodiac.
The sun formed when a cloud of gas and dust collapsed. The core was squeezed so tight that nuclear fusion began. Hydrogen atoms combined to form helium and give off energy. The sun shines by nuclear energy. Some of it takes the form of light. Visible light waves are between the infrared and ultraviolet on the electromagnetic spectrum.
Someday the sun will exhaust its hydrogen. It will then burn helium to form other elements. Toward the end of its cycle, the sun will become a red giant. Its outer shell of gas will expand. Its core will shrink. The core will become a white dwarf and eventually a burned-out ember. Heavier elements are made when massive stars explode as supernovas. The elements fly into space. The sun is a hydrogen bomb.
Moon
Bob Berman wrote about crescent shapes and how common they are in the universe. We can create a crescent by holding a ball to a lamp and viewing it from behind. Berman notes that the moon appears as a crescent when it is closer to the sun than we are.
Crescents younger than 14 hours cannot be seen. The two-day-old moon is easy.
As the moon waxes, earthshine dims. An almost full earth illuminates a thin crescent.
I do not see a man in the moon. I see a foot with three toes. The heel is the Sea of Serenity. The arch is the Sea of Tranquillity. The toes are the Seas of Crises, Fertility and Nectar.
June 18, 2008, I stood outside my apartment at the Village at Vanderbilt where I had observed a lunar eclipse four months earlier. I looked at a full moon through binoculars. What I noticed was a foot with three toes and the darkness of solid lava contrasted with the brightness of the southern highlands. The maria are dark because the iron-rich lava reflects less sunlight.
I saw Tycho. I saw the backwards Y composed of craters Copernicus, Aristarchus, Kepler and Grimaldi.
By June 22, darkness had engulfed the three toes and half of Tranquility. The left side of the moon was lit.
The moon orbits from west to east, rising 50 minutes later each night.
It is visible in the sky less than half the time.
Full moons rise in the east at sunset and set in the west at sunrise. I recall full moons rising above the orchard on Aiken Road. A full moon is the only phase which can be seen all night. Harvest moons are no bigger or brighter than other full moons. What distinguishes them is that they rise about 30 minutes later on successive nights due to a narrow angle between the ecliptic and the horizon in the fall.
The sun's rays hit a full moon directly. There are no shadows. The features of the moon are best seen along the terminator at first and last quarters when there are shadows. The terminator is the line dividing day and night.
The moon is locked by Earth's gravity. It rotates once as it orbits the earth, keeping the same side toward us.
The moon was created when a Mars-like object impacted the earth in the early period of the solar system. Part of the earth was knocked out and became the moon. The impact caused the earth to tilt 23 1/2 degrees on its axis. The axis is the imaginary line from pole to pole.
The dark areas on the the moon are solidified lava. Lava seeped from the moon's interior and covered the lowlands. The bright highlands are covered with craters.
That there are fewer craters on the far side of the moon indicates that its crust is thicker. The Russians were the first to photograph the far side.
Planets
The ancients called the planets "wanderers" because they moved in relation to the stars. They identified these wanderers with gods and goddesses. Jupiter was named after the king of the gods. Venus was named after the goddess of love. The more observant noted that the planets, sun and moon stayed inside a narrow band of constellations. This band became known as the zodiac (zoo) because it was comprised of animals.
Of course, the planets are not gods and goddesses. Nor are they simply lights in the sky. They are places, worlds, like and unlike our own. We still talk of planets being "in" constellations, knowing that it is another illusion. It makes them easier to find. When we say that a planet is "in' a constellation, what we mean is that it is in the direction of that constellation. That the planets, sun and moon stay inside the zodiac proves the flatness of the solar system. Its parts revolve in the same plane.
From the Wal-Mart parking lot in Lebanon, Tennessee, I used binoculars to view an alignment of Saturn, Mars and Regulus near a four-day-old moon. I observed the moon's terminator separating day and night and earthshine, that ghostly light reflected from Earth to the moon and back to Earth. The drama took place in the constellation Leo in the west after sunset. Saturn, Mars and Regulus lined up like Orion's belt to the right of the moon. It was the night of July 6, 2008.
On July 10, my cousin got out his reflector, and we looked at the first quarter moon, Saturn, Mars and Jupiter. We had a nice view of the moon's craters in the southern highlands. Central peaks were visible. Saturn and Mars were in conjunction in Leo, two degrees apart. Saturn was brightest, and we saw its rings. I recalled that Galileo described them as "handles." Saturn and Mars will not be this close again until 2022. We saw three of the Galilean moons around Jupiter. The fourth had to be in front of or behind the planet. We located the summer triangle, and I brought up how massive Deneb is. Its absolute brightness is greater than all other 1st magnitude stars.
Mercury circles the sun in 88 days. It flits back and forth from the western sky at sunset to the eastern sky at dawn.
Venus returned as the "evening star" in August. It takes 19 months to journey around the sun and return to the same place in the sky.
Venus is behind the sun at superior conjunction and between the earth and sun at inferior conjunction.
A conjunction is when two celestial bodies appear close in the sky.
Venus will transit the sun, June 6, 2012. It will appear as a black dot moving across the sun's surface.
Mars circles the sun in 697 days, less than two Earth years. Mars is closest to Earth during opposition, when it is on the opposite side of us from the sun. Opposition occurs every 22 months.
The Phoenix Lander is the latest spacecraft to look for life on Mars. Phoenix is analyzing Martian soil and is said to have found water ice. The public will not become excited until a man walks on Mars or undisputable fossils are found.
Jupiter is made of hydrogen and helium. It has no surface. When we view Jupiter, we are looking at the tops of thick clouds. Jupiter's rapid rotation has stretched the clouds into parallel bands. Light bands are called zones. Dark bands are called belts. The equatorial zone surrounded by belts is an Oreo cookie. The Great Red Spot looks orange now.
The Red Spot is shrinking. It is a storm, and all storms eventually play out. The Red Spot has the characteristics of a hurricane, strong winds and a circular motion. It has lasted so long because there is no land to slow it down.
In June, 2008, Jupiter was in Sagittarius at -2.7 magnitude. Jupiter circles the zodiac in 12 years.
Saturn too is made of hydrogen and helium. Yellow and gold bands make up its atmosphere. The Hubble Space Telescope imaged Saturn's northern and southern lights. Titan is Saturn's best known moon. It is the second largest moon in the solar system after Jupiter's Ganymede.
Saturn takes 29 1/2 years to complete one revolution of the sun. The rings are best seen near opposition. Right now, they are closing.
Saturn is in Leo as I write. The apparent distance between Saturn and Regulus will increase as the planet moves eastward.
Saturn will be behind the sun for two months before reappearing in the morning. The rings will be even more edge-on.
Uranus is in Aquarius. It circles the sun in 84 years.
William Herschel named Uranus' moons after Shakespeare's characters. Ophelia, Juliet and Desdemona are three tragic women .
Oberon, Titania and Puck are from A Midsummer Night's Dream.
Players from The Tempest are Prospero and his daughter Miranda, her man Ferdinand, Ariel and Caliban.
Neptune is in Capricornus. It circles the sky in 146 years. We seldom hear of the German who discovered Neptune: Johann Gottfried Galle.
Pluto will be in Sagittarius until 2024. It takes 248 years to circle the sun. Like Uranus, it rotates on its side.
I defended Pluto for a while. Now I think it is a Kuiper Belt Object. That Pluto crosses Neptune's orbit casts suspicion on its status as a planet. Clyde Tombaugh discovered Pluto at the Lowell Observatory in 1930. Its demotion demotes Tombaugh.
Pluto is the last planet to be explored. New Horizons arrives in 2015. That Pluto has three moons supports the idea that it might be a planet. Pluto was the god of the underworld. Charon was the boatman who ferried the dead across the river Styx. Nix was the goddess of night. Hydra was a monster.
Meteors
The Perseids are the most reliable meteor shower. Other important showers are the Leonids and the Geminids. Leonids peak November 17/18. Geminids peak December 13/14. The Leonids have been known to be spectacular. The problem is that November nights are cold. I may try to see them in 2009 as there will be no moon.
The Leonids of 1833 are legendary. It was a meteor storm. An estimated 100,000 meteors fell per hour. The superstitious believed it to be the end of the world. The Leonids are associated with the comet Tempel-Tuttle. Their radiant is in Leo's sickle. The "id" suffix means "from."
Bright meteors leave trails. Objects no larger then sand are so bright because temperatures reach 4,000 degrees. Also, being seen against dark skies exaggerates brightness. Meteors coming straight at us appear as stationary bursts of light.
Stars
Stars rise four minutes earlier each night as the earth circles the sun. Stars rise two hours earlier each month and, after a year, will be back where they were originally.
Changes in longitude do not affect the way we see the sky. Changes in latitude can affect it dramatically. Flying from Santiago to Sydney, the sky will look the same. Flying from Sydney to Reykjavik, there will be big changes.
If we were at the equator, we would see all the stars in a year. At the north pole, Polaris would be overhead and we would see only the stars in the sky's northern half. They would circle us, neither rising nor setting. At the south pole, we would see only the south circumpolar stars. If we were floating in space away from the earth, we would see all the stars in all directions. It is easy to see how the idea of a "celestial sphere" developed even though it does not exist.
There are 88 constellations, the number of keys on a piano. Western civilization inherited the constellations from the Greeks and Romans. Some look like what they are supposed to. Others do not. The Big Dipper certainly looks like a dipper. As part of Ursa Major, it is circumpolar, meaning that it is close enough to the north celestial pole to not rise and set at mid-northern latitudes. It is seen all night. The Dipper is an asterism, a well-known group of stars which is not a constellation. Orion's Belt, the Summer Triangle and the Great Square of Pegasus are asterisms.
Constellations are not real. They are imaginary star patterns created by farmers, shepherds, poets and astronomers. Farmers relied on the stars to know when to plant and harvest crops. Shepherds watched the night sky as they tended their flocks. Poets invented stories about gods and heroes which have passed through the generations. The Greeks gave us 48 classical constellations. Even they were influenced by the Babylonians. 40 more were added by Europeans during the scientific revolution. The Polish astronomer Hevelius added Leo Minor. Dutch navigators Keyser and de Houtman added Phoenix. Frenchman Nicolas de Lacaille created 17 constellations while in South Africa. The International Astronomical Union divided the entire sky into 88 sections, adhering to classical boundaries whenever possible. Now every object in the sky is part of a constellation.
The end stars in the bowl of the Big Dipper are the pointers. They point to Polaris, the North Star. Polaris is still getting closer to true north, the point directly above Earth's axis. The axis is the imaginary line running from the north pole through the south pole. Polaris was not always the north star nor will it always be. Thuban was the north star 4,500 years ago. 13,000 years in the future, it will be Vega. Precession of the equinoxes causes this shift. Over 26,000 years, the earth wobbles like a top because the sun and moon pull on it.
The constellation Draco winds between the dippers. Draco was the dragon killed by Hercules when he took the golden apples from the Garden of the Hesperides. The Hesperides were nymphs who tended the garden.
That Greek myths survived into the age of science is a testimony to the marvelous imaginations of those ancient people. The word "myth" comes from the Greek "mythos," meaning story. There are creation myths telling how the world came to be, explanation myths attempting to explain natural phenomena and quest myths, stories of heroes and epic adventures.
The story of Hercules is in the stars. We see the Nemean lion (Leo) and the crab (Cancer), vanquished by Hercules as part of his 12 labors. Hercules strangled the lion with his hands. The constellations in general depict man's conquest of the animal world.
The handle of the Big Dipper curves toward Arcturus. Orange Arcturus in Bootes the herdsman is the 4th brightest star. Bootes is accompanied by Canes Venatici, the hunting dogs. They chase the bears around the pole. The Whirlpool Galaxy (M51) is in Canes Venatici.
Spica is the 1st magnitude star in Virgo the virgin. Spica is found by extending the curve of the Dipper's handle through Arcturus. Spica is one of four bright stars which can be covered, or occulted, by the sun and moon due to its proximity to the ecliptic. Regulus, Antares and Aldebaran are the others.
Virgo is associated with the Earth goddess Demeter and her daughter Persephone. Persephone was abducted by Pluto and taken to the Underword. Zeus brokered a deal whereby Persephone would spend summers with her mother and winters with her husband. In this way the Greeks explained the seasons.
The Virgo supercluster is called the Realm of the Galaxies. When we look toward this supercluster, we look away from the plane of the Milky Way.
In Greek mythology, the Pleiades were seven sisters. Orion the hunter chased them across the sky. Orion developed a special bond with Artemis, Apollo's twin sister. They shared the hunt. Apollo grew jealous and sent a scorpion to kill Orion. Thus Orion and Scorpius are never in the sky at the same time, at least not in the northern hemisphere. I saw them together in Australia.
Some people see seven Pleiades. Others see six. One story names Merope as the Lost Pleiad. She married a mortal and hides herself in shame.
The Hyades, an open cluster in Taurus, are half-sisters of the Pleiades. This V-shaped star cluster near Aldebaran is actually far beyond it. The Pleiades are also in Taurus and ride the bull. Star lore is fascinating even though it is about man's imagination and not scientific reality.
Auriga the charioteer carries a goat on his shoulder and two kids (little goats) on his arm. Capella is the 6th brightest star.
Scorpius is a constellation which looks like what it is supposed to be. From my parents' front yard, I watched it crawl silently across the sky, moving low on the horizon. First magnitude Antares is like Betelgeuse in that both are red giants. They are near death. Shaula is the bright star in the scorpion's tail.
Libra the scales is the only non-living constellation in the zodiac. It was once considered to be the scorpion's claws.
Sagittarius the archer killed the scorpion to avenge Orion. Sagittarius is shaped like a teapot. Star clouds resemble steam rising from its spout. Locate two star clouds: large and small. The Trifid nebula is found in Sagittarius. It is divided into three lobes by dust lanes. A star inside causes its hydrogen to glow.
The Orion Nebula (M42) is a stellar nursery like the Pleiades. Stars are forming from gas and dust. The Horsehead Nebula is in Orion under Alnitak, the first star in the belt. The Horsehead is a dark nebula. We see it because Alnitak lights up the gas behind to trace an outline.
Constellations fit together to create scenes. Orion's dogs, Canis Major and Minor, are chasing Lepus the hare. Sirius in Canis Major is the brightest star because it is close, 9 light-years away. Sirius is blue and shines at -1.44 magnitude. Blue stars are young and hot. Canopus, the second brightest star, is dimmer than Sirius only because it is farther away.
Vega, Deneb and Altair make up the Summer Triangle. Vega in Lyra the lyre is the 5th brightest star. The lyre is the only musical instrument in the sky, and Orpheus saved the Argonauts from the sirens by playing it. The Ring Nebula (M57) in Lyra is a planetary nebula. It would be better if planetary nebulas were simply called dying stars.
Cygnus the swan flies overhead in summer. The Cygnus star cloud is a bright region of the Milky Way. Deneb is huge, 60,000 times more luminous than our sun at 2,600 light-years away. The Greeks saw Cygnus as Zeus in the form of a swan. He seduced Leda, queen of Sparta, causing her to lay eggs from which hatched Castor and Pollux. These twins sailed with Jason and the Argonauts in their quest for the Golden Fleece.
The constellations Aquila and Aquarius are related in myth. Aquarius the waterbearer is Ganymede. Zeus sent his eagle to fetch him because he wanted him as his personal cup-bearer. Ganymede fetches water from the river Eridanus. 1st magnitude Achernar in Eridanus is at the river's end.
Delphinus the dolphin, Pisces the northern fish and Capricornus the seagoat are in this watery part of the sky. Organizing stars into pictures to tell stories makes them easier to remember. The seagoat is Pan after he jumped in the river. Only part of him got wet, so that part changed into a fish.
The brightness of stars is measured by magnitude. There are 21 1st-magnitude stars from Sirius to Regulus. The higher the magnitude, the dimmer the star. Four stars have minus magnitudes: Sirius -1.44, Canopus -0.62, Alpha Centauri -0.27 and Arcturus -0.05. Stars with minus magnitudes are still called 1st-magnitude.
21 1st-Magnitude Stars
..1 Sirius --------- Canis Major
..2 Canopus -------- Carina
..3 Alpha Centauri --- Centaurus
..4 Arcturus ------- Bootes
..5 Vega ----------- Lyra
..6 Capella -------- Auriga
..7 Rigel ---------- Orion
..8 Procyon -------- Canis Minor
..9 Achernar ------- Eridanus
10 Betelgeuse ---- Orion
11 Hadar --------- Centaurus
12 Altair -------- Aquila
13 Acrux --------- Crux
14 Aldebaran ----- Taurus
15 Spica --------- Virgo
16 Antares ------- Scorpius
17 Pollux -------- Gemini
18 Fomalhaut ----- Piscis Austrinus
19 Becrux -------- Crux
20 Deneb --------- Cygnus
21 Regulus ------- Leo
1 Fred Schaaf has long been fascinated with Sirius. He claims to have seen it through his bedroom window at age six. I was 16 when I spotted it rising above the woods across the road from where we lived. Schaaf revels in Sirius' twinkling and many hues as its light passes through our atmosphere.
2 I saw Canopus from Australia. It is in Carina. Carina the keel was part of Argo Navis, the ship on which the Argonauts sailed. Modern astronomers thought this largest of constellations unwieldy and split it into parts.
3 The Alpha Centauri system represents the closest star at 4.4 light-years: 25 trillion miles. Alpha Centauri A is believed to be like our sun.
4 Arcturus loomed above my parents' back yard, where we played croquet and horseshoes as I labored to beat my friends at games in the 1950s and 60s. Arcturus is 37 light-years away. It has burned its hydrogen and is now burning helium. Bootes looks like a kite.
5 Vega is a blue-white sapphire dominating the Summer Triangle. There is evidence that it has a Jupiter-like planet.
6 Like so many stars, Capella turns out to be a double.
7 In Norse mythology, Rigel was a big toe of the giant Orwandil. When the other big toe was frost-bitten, Thor broke it off and threw it into the northern sky as Alcor, the star near Mizar in the Big Dipper.
8 Star pronunciation varies over time. Procyon is now pronounced pro-SY-on. I can remember by thinking of Cy Young, the great pitcher.
9 Achernar is the least famous of the 1st magnitude stars. In Australia, I pointed it out and asked a fellow stargazer what it was. He said, "That's Achernar." The moment stayed with me. Achernar is isolated at the river's end.
10 Red giant Betelgeuse in Orion is the most famous star. It is big. If put in our sun's place, it would reach beyond Mars and possibly to Jupiter. Betelgeuse will go supernova in a few million years.
11 Hadar is a name for Beta Centauri.
12 Acrux is a name for Alpha Crucis.
13 The constellation Aquila contains 1st-magnitude Altair. Altair lies between two dimmer stars. In the movie, Forbidden Planet, the action takes place on Altair 4, the fourth planet from Altair.
14 Occultation is when one celestial object hides another. Aldebaran is one of those four 1st-magnitude stars which can be occulted by the sun and moon. It is the bull's-eye in Taurus. Aldebaran is converting helium into carbon.
15 Virgo is pictured with wheat in her left hand. Spica is translated to mean "ear of wheat."
16 Antares in the scorpion is another 1st-magnitude star which can be occulted. It was during an occultation that its green companion was discovered. Antares is like Altair in that it is flanked by two stars.
17 Castor and Pollux are the famous twins in mythology and the two bright stars of Gemini. Pollux is 1st-magnitude. Astronomers believe it has a planet albeit a Jupiter-like blob. Castor and Pollux are four degrees apart in the sky and 18 light-years apart in space.
18 I always stumbled on the pronunciation of Fomalhaut. It is fom-a-lawt. The h is silent. Fomalhaut is the mouth of the southern fish and believed to have at least one planet.
19 Becrux is Beta Crucis in the Southern Cross. It lies near a dark nebula known as the Coalsack.
20 Medieval Arabs named the stars. "Deneb" came from "Dhanab," Arabic for "tail," and Deneb is the tail of the swan.
21 Regulus is a flat star. Its equatorial diameter is greater than its polar diameter. Rapid rotation causes flatness. Leo inspired the Egyptian Sphinx.
Messier Marathon
My Messier Marathon took place, April 25, 2009, at Mark Manner's Spot Observatory, 50 miles west of Nashville on I-40. I had looked forward to this as a BSAS member. Fortunately, the sky was clear. Frenchman Charles Messier was an 18th century comet hunter who listed 110 fuzzy objects so he would not mistake them for comets. Ironically, it is for this throwaway list that he is remembered.
It reminded me of Australia, walking out and seeing bright stars after being so long at Vanderbilt. I even hooked up with a married couple. He went down the list of Messier objects with machine-like precision, locating "targets" in his big reflector. She worked at the Sudekum Planetarium in Nashville and talked about the Kepler project and its search for exoplanets.
We experienced a cross-section of objects. It is unrealistic to try to see them all in one night. After several open clusters, they start to look alike, and even in late April, it gets chilly after midnight. The M numbers I saw could have been pulled out of a hat, but here is how it turned out. It felt good to be out of the city under a dark sky.
M1 - The Crab Nebula in Taurus is the remains of a supernova. A star exploded, leaving expanding gas and a rotating pulsar. The Chinese recorded the event in 1054.
M35 - Open cluster off Castor's toe in Gemini containing 200 stars.
M36 - Young open cluster in Auriga. The 60 stars appeared as a fuzzy object in the center of the telescope's field of view.
M37 - Dense open cluster in Auriga with a red giant in the middle. Open clusters are found along the plane of the Milky Way.
M38 - Another open cluster, this one in the central part of Auriga. Open clusters break up after a few million years because of gravitational influence from nearby stars.
M40 - Double star in Ursa Major.
M42 & M43 - M42 is the Orion Nebula and everybody's favorite. It resembles a peacock, maybe a turkey. M43 is close.
M44 - The 200 stars of he Beehive cluster were bright and sharp in the reflector. Also known as Praesepe (Latin for "manger"), the Beehive lies in the center of Cancer. In mythology, Hera sent the crab to attack Hercules. He squashed it.
M45 - This is the Pleiades although we did not observe it through the telescope.
M65 & M66 - Two galaxies in Leo 35 million light-years away. M66 is dominant. M65 is edge-on in our line of sight.
M67 - Open cluster in Cancer found by locating the Hydra's head. Colors indicate these are mature stars: yellow, orange and red. The more red giants, the older the cluster.
M81 & M82 - Two galaxies in Ursa Major. M81 is a spiral. M82 is disturbed. They are only 100,000 light-years apart, and each could be clearly seen from the other.
M95 & M96 - Two galaxies in Leo along the lion's belly. M95 is barred. M96 is a spiral. M96 is the brightest.
M97 - Called the Owl Nebula because someone thought its details resembled the eyes of an owl. This is a so-called "planetary nebula," a dying star giving off a shell of gas. It has nothing to do with planets. It appeared as a smudge in the middle of the eyepiece.
M105 - Elliptical galaxy in Leo.
M109 - Spiral galaxy in Ursa Major. Averted vision helped in spotting this oval blur.
We saw an array of spring constellations: Virgo and the diamond-shaped Corvus. Saturn lay beneath Leo. Early on, Orion was sinking in the west. Later, Scorpius was rising. Vega was well up. The party ended with Mark showing me his slides. We talked about eclipses. He had taken a nice picture in Hawaii of the 1991 solar eclipse.
Perseid Meteor Shower
I became aware of the Perseid meteor shower in 1961. In 1964, the Perseids were spectacular, and I was spoiled. I counted 351 meteors the night of August 11 and morning of August 12. Many were fireballs, leaving trails. I always dreamed that one day I would experience another meteor shower like that. Most years it was either cloudy or the moon was out. I counted over a hundred meteors from my yard in Lebanon, Tennesse, in 1978. As the years went on, the problem became one of getting away from city lights, finding skies dark enough to make the effort worthwhile.
Most meteors are 50 to 100 miles up. They are no bigger than grains of sand. They enter the atmosphere at 40 miles per second. Nearly all are vaporized. The radiant for the Perseids is at the top of Perseus' head.
I am planning a meteor watch for the 2010 Perseids. There will be no moon. I may have to travel or get with a star party. I am in touch with Bryan Wilburn of the Denver Astronomical Society.
The Milky Way -
When I saw the Milky Way arching across the night sky as a teenager, I gave it little thought. It was a glowing band of light, nothing more. In my 30s, I realized that the Milky Way is the galaxy in which our sun and planets reside. Our solar system lies on the edge of one of the galaxy's spiral arms.
We see the Milky Way stretching from northeast to southwest in summer. The Milky Way circles the sky although part of it is never seen from the United States. I saw the southern piece from Australia. Light from the Milky Way is the combined glow of billions of suns thousands of light-years away. The galaxy appears as it does because of its frisbee shape. It bulges in the center and tapers at the edges like a fried egg. Our solar system is located toward the outer rim. When we view the star clouds in Sagittarius, we look toward the Milky Way's center. Looking in the opposite direction, we look toward the rim. Looking perpendicular to the Milky Way, we look out the top or bottom of the galaxy where stars are scarce. The Milky Way is rotating. It spins once every 200,000 years. If I had known this as a teenager, I would have been a genius. It is revelation to look at the Milky Way and to understand even in some elemental way what we are seeing.
Parts of the Milky Way are obscured by dust and gas. These are not holes. The Great Rift splits the part moving from Cygnus toward Sagittarius. In summer, we look toward the center of the galaxy in the direction of Sagittarius. In winter, we look toward its outer rim beyond Orion.
Tracing the Milky Way around the summer sky, we first notice it in the direction of Perseus, Cassiopeia and Cepheus. In Cepheus, a constellation resembling an inverted house, the Milky Way comes close to the north celestial pole. From there, it flows to Cygnus. Eagle-Eye Barnard studied the Milky Way, and it was he who first realized that the dark patches were clouds of dust and gas and not holes. The Great Rift starts at Deneb and extends almost to the Southern Cross. It divides one-third of the Milky Way into two apparent streams. Barnard's starry band flows into Scutum, and he referred to the star cloud in Scutum as "the gem of the Milky Way." It moves southward beyond Centaurus, coming close to the south celestial pole near Crux. We follow it past Canopus and between the Dog Stars. It is less brilliant. It passes the feet of Gemini, and suddenly we are back at Perseus where we first noticed this starry circle. Seen from afar, the Milky Way is a flat spiral with arms coiling around a central mass. Our own star cloud is in one of the spiral arms.
Stars move around the galaxy although not in one piece. They move like the planets do around the sun. Stars near the hub of the galaxy move faster. Those toward the rim move slower.
Astronomers have identified five spiral arms around the Milky Way galaxy. These are the Orion, Cygnus, Sagittarius, Perseus and Centaurus arms. Our solar system is in the Orion arm.
Cosmology
The Hubble Space Telescope has added as much to our confusion as to our understanding. Hubble images illustrate the chaos of the universe and convey a feeling of being lost in space. The Pillars of Creation in the Eagle Nebula in Serpens provides some reference. Star formation goes on in the fingerlike spires of gas.
The Hubble Ultra Deep Field is the most pervasive photographs taken in astronomy. The HUDF imaged 10,000 galaxies and looked back 13 billion years to when the universe was 700 million years old. HUDF penetrated an area in the constellation Fornax 1/10 the size of a full moon. Astronomers compared the HUDF to "looking through an 8-foot-long soda straw." We begin to comprehend the immensity of the universe and its billions and billions of galaxies.
The universe was pure energy after the Big Bang. It was not long before some of it to froze into matter. A wall of radiation may keep us from seeing the beginning. But even if we did see the Big Bang, what would it mean? We would still question. Only when we are united with God through Jesus and the Holy Spirit will we have true understanding and lasting peace.
Exoplanets have been the big thing since 1995. These are planets circling stars in other solar systems. 403 are confirmed. They are found by indirect methods, not by telescopes or imaging. Astronomers measure the gravitational tug of exoplanets on their parent stars. That most are gas giants like Jupiter is probably due to the limitations of current technology. There may turn out to be many terrestrial exoplanets.
Our immediate reaction is to think there must be other civilizations. And there may be. We do not know. Ours may be the only one, and the rest of the universe, regardless of its size, may be leftover material from God's creation of Earth. Sawdust on the floor. We are still not alone if there is a loving Creator.
Scientists believe that if matter is arranged in a certain way, there will be life. I have doubts. Life is more than a particular arrangement of atoms and molecules. It was created by a divine spark, the same spark which created the singularity before the Big Bang. Without God, no universe and no life.
New Horizons
The New Horizons spacecraft was launched at Cape Canaveral in January, 2006. It will fly by Pluto and its moons in July, 2015, completing a three billion mile journey. New Horizons will study Pluto, then fly toward the Kuiper Belt. The spacecraft uses nuclear power to generate electricity. Home base is the Clyde Tombaugh Operations Center in Boulder, Colorado.
Kepler Mission
The Kepler telescope will search for Earth-like planets. It was launched in March, 2009, and will survey 100,000 stars. Stars are suns and since 1995, 403 exoplanets have been found. Most are huge balls of gas resembling Jupiter. The Kepler telescope is been designed to search for small, rocky worlds. Scientists will look for planets in "habitable zones," those capable of sustaining water. We still wrestle with the question of whether there is life beyond Earth.
Kepler will relay data for 3 1/2 years. It is no simple matter to register smallish objects orbiting stars at such distances, and it will be done by indirect means. Transits are the key. Kepler will record fluctuations in starlight as planets transit their suns. Times between transits will be measured. Kepler is surveying stars in the direction of Cygnus.
Gliese 581c and Gliese 581d are small exoplanets inside the habitable zone of their parent star. There may be liquid water. There may be life. Both planets are 20 light-years from Earth. Gliese was a German astronomer who compiled his Gliese Catalog of Nearby Stars.
James Webb Space Telescope
The James Webb Space Telescope is scheduled to go up in 2013. It will seek out the most distant objects. JWST is infrared, so data will be gathered from the infrared range of the electromagnetic spectrum. JWST will penetrate dust to observe the first galaxies formed after the Big Bang.
I had no clue who James Webb was, so I did my research. Webb was the Administrator of NASA 1961-1968. He led NASA in the years following Kennedy's moon speech.
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Originally written 2008
Revised 2009
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