CHESHIRE
STAR WATCH
Giving The Sky Time
To Changeby Jim Maynard
Star date: 04:11:97
Last week we discussed the possibility of an asteroid or comet impacting with the Earth. This week, we will give the skies one more week to change for new objects to become visible; after all, the sky only changes at the same time of day about one degree per day.
Two events brought this week's article
about. First, I have been studying for an exam all week, and it made me
realize that what I first fell in love with about astronomy is not figuring
out the maximum wavelength of a star given a certain surface temperature,
or deducing the radial velocity of an object given the Doppler shift of
its Bauder emissions (although I do love the beauty of the math involved),
but the amazing facts there are about the universe around us. I know that
the beauty of many objects in the night sky is what drags me out of the
house to set up my telescope on a cold winter night, but it is the incredible
facts which keep my nose in astronomy and physics books. I'm almost certain
that is what drives many professional astronomers.
What Second, the local astronomy scene in Keene suffered quite a loss March 31st when Bill Breckenridge, who headed the Keene amateur astronomers, died. He was quite a man and I will never forget him. I dedicate this week's article to his memory.
On to some facts!
The
surface of the sun is only about 6,000 Celsius, but corona of the sun (the
outermost layer of the sun) is over a million degrees Celsius. However,
if you were to suddenly find yourself in the corona of the sun, you would
not burn to death, but rather you would instantly freeze to death.
Why? The answer to that depends on the difference between temperature and heat. Temperature is defined as the average speed of a material's atoms or molecules vibrating. Heat is defined as the total vibrational energy of all the atoms in the material. A cup of coffee and a vat of coffee may have the same temperature, but the vat of coffee has vastly more heat. This is why you can stick your hand in a 212 degree oven, but cannot stick your hand (for very long) into boiling water.
The temperature of the corona of the Sun (the average velocity of it's atoms) may be one million degrees Celsius, but it is so thin, you would instantly freeze to death.
Light
travels 186,231 miles per second in a vacuum. That means light takes 1.25
seconds to reach us from the moon, eight minutes from the sun, four years
from the nearest star, and 2.2 million years to reach us from the nearest
galaxy. The light we see now from the most distant objects we can view left
it's home over 13 billion years ago.
The magnetic fields of the Earth switch polarity (the north pole becomes the south pole and vice versa) in a random, unpredictable fashion. The magnetic field of the sun, however, changes polarity in a regular, periodic fashion every 11 years; it is what drives the sunspot cycle. The most amazing part is, nobody knows causes the polarity chances.
A star the size of the Sun will first swell up to a size large enough to engulf the Earth, and perhaps Mars, and then will shrink down to a white dwarf, about the size of Earth. A star a few times the mass of the Sun will shrink to a neutron star the size of a city, and like a figure skater bringing in her arms, will start to spin faster and faster, becoming a pulsar. Aster which once spun on it's axis a leisurely few times a month can start spinning thousands of times a second with amazing regularity, sometimes beaming regular pulses of energy to Earth. In fact, when they were first found, pulsars were believed to be beacons from an extraterrestrial civilization, and were called LGM's, for Little Green Men".
The substance of a white dwarf is made from perhaps the most bizarre in the universe - degenerate matter (a formless soup of protons, neutrons and electrons which previously made up the star's component atoms). Degenerate matter is a gas nearly indistinguishable from a metal. It is so dense that a single teaspoon of it weighs about the same as an elephant. One tablespoon of a neutron star, however, is made of just protons and neutrons (known collectively as neucleons), and could weigh millions of tons.
Since the Moon is slowly heading away from the Earth, in 10,000 more years, there will be no more tides. In less than a thousand years, there will be no more solar eclipses.
The North Star, Polaris, is slowly pulsating every four days or so. This is an actual pulsation of the entire star, not a rotational pulsing, as in the case of a pulsar. However, the pulsations are slowly grinding to a halt, and may be non existent by the year 2000. Although Polaris is i the right stage of it's life to pulsate, it is in the wrong period of it's life (according to our current theories) to stop pulsating. Astronomers do not know what is causing it to attenuate it's pulsations.
Good skies and clear viewing.
This site operated by 
