Download Mon Oct 7, 2013 MOON AND SATURN, VENUS Last night, if you

Mon Oct 7, 2013
MOON AND SATURN, VENUS
Last night, if you had a clear, unobstructed view to the west horizon at sunset, you might have caught sight of the moon,
a very slender crescent low in the western sky. Just above this new crescent moon a star appeared as darkness set in.
That star was actually the planet Saturn, nearly a billion miles away. Farther to the south and a bit higher up in the sky
there was another planet, Venus, which shone as a brilliant star-like object in the constellation Libra the Scales. Tonight
the moon is a little higher in the sky, and its crescent shape is a little bit fatter. Saturn is down below and to the right of
the moon, but Venus is much closer to it, or rather, the moon now appears much closer to Venus, which is to the left
and a little above the moon at sunset. The moon is a fast mover, and tomorrow night it will be above Venus, continuing
its eastward trek as it moves along in its orbit of the earth.
Tue Oct 8, 2013
SPUTNIK, SATELLITES
On October 4, 1957, the world’s first artificial satellite, Sputnik, was sent into earth orbit from a launch site in the Soviet
Union. A few months later, the United States successfully launched Explorer 1, and another satellite now revolved about
the earth. Today, there are thousands of satellites in orbit; and every so often, you can see one passing overhead. It
looks like a moving star, or like a light from a high-flying jet, but the satellite moves along at a pretty good clip, and yet
you can't hear any sound coming from it. These satellites reflect sunlight down to the darkened earth, and so are visible
for a couple of hours after sunset or a couple of hours before sunrise, a time when we are in earth's shadow, but the
satellite is just outside it. Satellites typically travel from west to east, except for those in polar orbits which move along a
north-south path.
Wed Oct 9, 2013
MOON IN OPHIUCHUS
This evening the waxing crescent moon can be found in Ophiuchus. This very old constellation takes up a large part of
the southern sky, but it doesn’t have any really bright stars, so not too many folks know it. There are bright stars down
below the moon, but they belong to the constellations Sagittarius and Scorpius, plus that really bright star off to the
west at sunset is actually the planet Venus. Anyway, “Ophiuchus” is an old Greek designation which means, “serpent
bearer”, and the star figure is typically portrayed as a big, bearded fellow holding a very large snake. His actual name is
Asclepius, the same name as that given to the snake-entwined staff that is the symbol of the medical profession. In
mythology, he was a healer of the sick, and the snake’s diluted venom served as a medicine. Doctors and others who
practice medicine take the Hippocratic oath, where they “swear by Asclepius,” to help the sick. Tonight the moon is in
the foot of the healer.
Thu Oct 10, 2013
HOW MANY STARS?
How many stars are there in the Universe? Well, on a clear dark night you can see a couple thousand up there above
you. The best estimates of the number of stars in the Milky Way suggest there are perhaps 150 to 200 billion stars in our
home galaxy. Of course there are other galaxies, billions of them, each containing billions or trillions of stars. So how
many stars? Here’s a good way to get an idea. Next time you’re at the beach, count the number of grains of sand you
can hold in your hand. You’ll be at it a while; there’s roughly 10,000 sand grains in each handful. Now count all the grains
of sand on the entire beach. Follow that up by counting all the grains of sand on all the beaches of Florida, and then
count all the grains of sand on all the beaches of the world. There are more stars than that in our Universe.
Fri Oct 11, 2013
OLBERS AND HIS PARADOX
Heinrich Wilhelm Olbers was born on October 11, 1758. A physician and an amateur astronomer, he discovered the
asteroids Pallas and Vesta in the early 1800’s, and suggested that the asteroid belt was the remnants of a destroyed
planet (nowadays we think it’s planetary material that was never able to build itself into a planet, thanks to the
gravitational effects of Jupiter.) But he is best known for something called, Olber’s Paradox. He asked a simple question:
"why is the sky dark at night?" Now that seems a bit silly - after all, the sky is dark at night because the earth rotates into
its own shadow, what we call night. ”I know that,” he said. But if the universe is infinite in size, then that means there's
an infinite number of stars out there. So no matter where you look, you'll eventually find a star - the sky should be
ablaze with light! But it's not. This suggests that the Universe is perhaps not infinite, and that there was a definitive point
in time in which the Cosmos began, and also that the Universe is expanding!