Night Sky (Astronomy blog)

[Jim Colyer]

I started an astronomy blog this summer. Help me correct errors and express ideas better. Nothing comes easy when you're Forrest Gump.

http://jimcolyer.com/papers/entry?id=207

NIGHT SKY
I went to the Sudekum Planetarium in Nashville and joined the Barnard-Seyfert Astronomy club. Yes, it is Barnard with two "a"s and Seyfert with two "e"s. The group meets on the third Thursday of every month at the Adventure Science Center. I am looking for dark sky sites so I can see the stars. What interests me is that BSAS meets regularly about an hour down Natchez Trace, far from Nashville's lights.

I gave $20 to Bill Griswold for membership. The BSAS newsletter, The Eclipse, comes by email. Terry Reeves is the club president. Phone: 386-3134

E. E. Barnard (1857-1923) was born in Nashville. He was a great observer and discovered the first Jovian moon since Galileo. He became an astronomy professor at the University of Chicago and photographed the Milky Way at Yerkes Observatory.

Carl Seyfert (1911-1960) was born in Cleveland. He came to Vanderbilt in 1946, and was influential in building Dyer Observatory. He was its first director. Seyfert died in a car wreck in Nashville.

July 17, 2008, I attended the meeting of BSAS at the Science Center. Terry Reeves gave a presentation with slides showing constellations and the location of Messier objects. There was discussion about star parties, when and where they should be held. The gal who operates the planetarium showed the night sky. She pointed out Saturn and Mars near Regulus in Leo.

I am looking forward to a Messier marathon. They are held in the second half of March.

Earth
It is not easy to believe that the earth is rotating. The ancients thought the stars rose nightly in the east and set in the west. This is an illusion caused by our spinning planet.

70% of the earth is covered by water. There are four oceans: Atlantic, Pacific, Indian and Arctic. 10% of the land is covered by ice.

Life began in the oceans, and our bodies are 75% water. All land creatures need water to survive. Plants invaded the land 400 million years ago. Plants give off oxygen which makes animal life possible.

Sun
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. The ecliptic is really the path of the earth's orbit around the sun. It is in the center of the zodiac.

The sun is a star. It is one of 200 billion stars in the Milky Way galaxy. It seems like a different animal or 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 away.

The sun formed when a cloud of gas and dust collapsed. Its core was squeezed so tight that nuclear fusion began. Hydrogen atoms combined to form helium and give off energy in the process. The sun shines by nuclear energy. Some of it takes the form of light. Visible light waves lie between the infrared and ultraviolet on the electromagnetic spectrum.

Someday the sun will exhaust its hydrogen. Then it will burn helium to form other elements. Toward the end of its cycle, its core will shrink. The sun will become a red giant. Its outer shell of gas will expand. We call this a "planetary nebula." Its core will be a white dwarf and eventually a burned-out ember. The heaviest elements are made when massive stars explode as supernovas. Elements fly into space. The sun is a hydrogen bomb.

Moon
Bob Berman writes about crescent shapes and how common they are throughout 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. We probably know this subconsciously, but how many of us think about it?

Crescent aficionados strain to see young moons. Crescents younger than 14 hours cannot be seen. A two-day-old moon is easy.

As the moon waxes, earthshine dims because the earth becomes a thin phase in the lunar sky. An almost full earth illuminates a young crescent moon.

The moon is like a mirror. The principle is the same. When we look into a mirror, light reflected from our face hits the mirror and is reflected to our eyes.

Look at earthshine through binoculars. Is earthshine bright enough to make out some of the moon's features?

June 18, 2008, I stood outside my apartment at the Village at Vanderbilt where I had observed the lunar eclipse four months earlier. I looked at the full moon through binoculars. What I noticed was the foot with three toes and the darkness of the solidified lava (maria) compared with the brightness of the southern highlands. The maria are darker because the iron-rich lava reflects less sunlight.

I saw the backwards Y composed of craters Copernicus, Aristarchus, Kepler and Grimaldi. I made out Tycho. Jupiter shown brightly in Sagittarius with a magnitude of -2.7.

By June 22, darkness had engulfed the three toes and half of Tranquility. The left side of the moon was lit. "Gibbous" is Latin for "hump."

The moon orbits the earth from west to east. It rises 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 a full moon rising above the orchard on Aiken Road. A full moon is the only phase which can be seen all night. The Harvest moon for 2008 was on September 15. Harvest moons are no bigger or brighter than other full moons. What distinguishes Harvest Moons is that they rise only about 30 minutes later on successive nights due to the narrow angle between the ecliptic and the horizon in the fall. Farmers and hunters historically relied on these full moons to finish their work.

The sun's rays hit the moon directly when it is full. No shadows are cast. The moon's features are best seen along the terminator at first and last quarters when there are long shadows. The terminator is the line separating night and day. Before a full moon, the terminator marks the sunrise line. After a full moon, it marks the sunset line.

I do not see a man in the moon. What I see is a foot with three toes. The heal is the Sea of Serenity. The arch is the Sea of Tranquillity. The toes are the Seas of Crises, Fertility and Nectar.

Planets
The ancients called the planets "wanderers" because they moved in relation to the stars. They identified the wanderers with gods and goddesses. Jupiter was named after the king of the gods. Venus was named for the goddess of love. Mars took its name from the Roman god of war. The observant noted that the planets as well as the sun and moon stay inside a narrow strip 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 mere 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 easy to find. That the planets, sun and moon stay inside the zodiac proves the flatness of the solar system. Its parts move 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 crescent 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 1st magnitude Regulus lined up to the right of the moon like Orion's belt. I could see the three at once through my binoculars. This was the night of July 6, 2008.

I was with cousin Larry on July 10, 2008. He got out his reflector, and we looked at a first quarter moon, Jupiter, Saturn and Mars. We had a good view of the moon's craters in the southern highlands. Central peaks were visible. We saw three of the Galilean moons around Jupiter. The fourth must have been in front of or behind the planet. Saturn and Mars were in conjunction in Leo in the west. They were about two degrees apart. Saturn was brightest, and we looked at its rings. I recalled that Galileo described the rings as "handles." Saturn and Mars will not be this close again until 2022. We located the summer triangle. I brought it up about how massive Deneb is. Its luminosity is greater than any of the other 1st magnitude stars.

Saturn will be behind the sun for two months before it reappears in the morning. Its rings will be even more edge-on. Saturn took its name from the Roman god of farming.

[austintorn@aol.com]

Good stuff, and good eyes.

The setting of a full moon may be a rare sight for some.

Another great thing about a moonrise or set is that you can note the earth's turning.

[austintorn@aol.com]

A story with a events of astronomy being a key part of it:

http://www.toequest.com/forum/anecdo...rone#post57899

[austintorn@aol.com]

Fifty thousand years ago, Elder Sapiens, well nigh almost 30 years old, sat outside the shelter as twilight ended, noting that the moon was pale and sickly, dim and feeble, much as he felt himself. ‘Twas not the best night for the Hunter Sapiens to be out… but the ever-present worries bred by these ancient times had won over his weariness, halting, if only for a time, his vitality from slipping away any further.

The crescent was brightening, as best it could, and he half-slept a while; then a dragging noise in the bush brought him to life. They were back, hauling a carcass. If there was danger about, he would’ve waved them off, but they was none, so he waved them on. No one had eaten much but leaves and berries for five days now, except for Infant Sapiens, who feasted on Mother’s milk.

Elder pointed to the dying moon and then to himself, but the Younger Sapiens motioned that he was fine.

Many tens of millennia ago, their communication had begun, faint and ethereal, only within themselves—symbols forming and connecting. This eventually led to gestures, preserved even to this day, as when people talk, along with their hands, even while on the phone! Grunts and simple references followed, then the basics of language.

The moon set, and the Homo Sapiens gathered round, friend and family, the night enveloping them, as evolution continued to sift the best from the rest, as ever it had done through death, our ancestors waning and waxing in strength.


About 50,000 years later, around 1100 A.D., Omar Khayyam, a rebel among the Islamics of his day would write about the moon. About 750 years later, Edward FitzGerald translated it into English verse; however, it never appeared in his published Rubáiyát, but had remained in his notebook:

Be of Good Cheer -- the sullen Month will die,
And a young Moon requite us by and bye:
Look how the Old one meagre, bent, and wan
With Age and Fast, is fainting from the Sky!

[Jim Colyer]

Develop this. We need stories with good science and astronomical themes.