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Skywatch for the week of October 25, 2021

Skywatch 10-25-2021.mp3

Mon Oct 25, 2021 DEATH OF TYCHO

“Let me not seem to have lived in vain.” These were the last words of the Danish astronomer Tycho Brahe, who after eleven bed-ridden days of suffering, died on October 24, 1601. Working before telescopes were invented, Tycho accurately measured the positions of stars and planets, proved that comets were objects in outer space, and believed that while some planets orbited the sun, the sun orbited the earth. A popular legend says that Tycho died because he didn’t go to the bathroom on time. He was at a banquet, and did not wish to insult his host by leaving early. As a result, his bladder burst, which killed him. In 1993, Brahe’s body was exhumed, and analysis of his hair seemed to show a lot of mercury; as an alchemist, had he accidentally poisoned himself? But a more recent autopsy shows that his mercury levels were almost in the normal range, supporting the opinion of the doctor who attended the astronomer as he lay dying; Tycho may actually have died from a burst bladder.

Skywatch 10-26-2021.mp3

Tue Oct 26, 2021 FARTHEST NAKED-EYE OBJECT

What’s the farthest thing you can see without a telescope? Off in the northeastern sky late this evening, you can find the answer to this question, but only if the skies are very clear, and very dark, and you know just where to look. It’s a very dim smudge of light that lies in the direction of the constellation Andromeda. But this small spot is neither little, nor does it have any physical connection with the stars of Andromeda, which are merely trillions of miles away. It’s not even a member of our Milky Way, but instead another galaxy, comprising 300 billion stars and approximately two and a half million light years away. One light year, the distance light can travel in a year, is roughly six trillion miles. So when you see the Andromeda Galaxy, you’re looking at something that is fifteen million trillion miles away – and that’s how far out your eye can see.

Skywatch 10-27-2021.mp3

Wed Oct 27, 2021 THE STORY OF PERSEUS AND ANDROMEDA

Well-placed in the eastern sky this evening are four stars which form a large square – this is the great square of the constellation Pegasus the Flying Horse. To the north of the square there’s Cassiopeia, which resembles a letter W. Queen Cassiopeia was a boastful woman who compared her beauty to that of the mermaids. In punishment, the sea god Poseidon sent Cetus, the sea monster, a scattering of stars below Pegasus, to devour Cassiopeia’s daughter, the princess Andromeda, marked by several stars between Cassiopeia and Pegasus. But the hero Perseus, a scattering of stars to the east of Cassiopeia, came to the rescue by showing Medusa’s head to the sea monster. Cetus looked at the gorgon’s snake-infested head, turned to stone and sank. Then Perseus flew off with Andromeda on the back of Pegasus, and a happy family reunion.

Thu Oct 28, 2021 CREATURES OF THE NIGHT

If you’re out trick or treating this weekend, and the skies are clear, you’ll have a chance to see the planet Venus in the west and the planets Jupiter and Saturn in the southeast after sunset. Besides this pretty sight, there are many constellations suited for Halloween. The three stars in the summer triangle overhead, represent man-eating birds that were chased from the Stymphalian swamps by the hero Hercules. At sunset, the constellations of Scorpius the scorpion is sinking into the southwest. A scattering of stars in the southeast this evening mark the location of Cetus the Whale – a sea monster in Greek mythology. Perseus the hero, over in the northeast, holds out the snake-haired head of the gorgon Medusa, while Draco the dragon guards the northern skies tonight. And after midnight, Canis Major rises in the southeast. He is associated with the three-headed dog Cerberus who guarded the gates of the Underworld.

Fri Oct 29, 2021 ALGOL, THE DEMON STAR

The constellation Perseus can be found in the northeastern sky this evening. In the old myth, Perseus slew the snaky-haired gorgon Medusa, and then carried her head with him in his other adventures. It was said that gazing upon her head would turn you to stone. Now in this constellation there is a star named Algol, which marks Medusa’s eye. The name Algol comes from its Arabic designation as “the demon,” and is also where we get the word, “ghoul.” Algol is a very unusual star – three stars, actually, what’s called a trinary star system, and two of those stars are so aligned with our world that about every three days, we can observe one star pass directly in front of the other - an eclipsing binary. When that happens, the light from this triple star gets quite a bit dimmer. To the ancients, this was like the winking of a demon’s eye. But no worries, looking at it this evening won’t turn you to stone. Algol is fairly bright tonight; but this Halloween, October 31st, 2021, the demon star will dim.