Skywatch for the week of October 21 , 2019
Tue Oct 22, 2019 BEN FRANKLIN’S HURRICANE In colonial America, Benjamin Franklin was hoping to observe a lunar eclipse on the evening of October 21, 1743. Anticipation soon turned to dismay however, as an hour before the eclipse was to begin, clouds and rain blew in from the northeast, and treated his hometown of Philadelphia to a most violent thunderstorm. He was all the more surprised therefore, when his brother in Boston told him that they had also had a storm, but it happened after the eclipse, which he got to see. But the storm had come from the direction of Boston. How did it hit Philadelphia first? Franklin reasoned that this must have been some special kind of storm. He gathered together weather reports and found that the storm had moved up the Atlantic seaboard, moving counter to the local surface winds. And so Ben Franklin was the first person to discover the cyclonic nature of a hurricane, and thus turned an astronomical defeat into a meteorological windfall!
Wed Oct 23, 2019 FOMALHAUT As we move toward the end of October, skywatchers may have noticed a fairly bright star over in the southeastern sky after sunset. It’s not the brightest star in the sky; in the southwest, the planet Jupiter outshines all other stars; below and to the right of Jupiter is the star Antares in the constellation Scorpius; and in the south is the planet Saturn, just east of Jupiter. But in the southeast, there’s really nothing else around anywhere near as bright as this one little star, which is not really such a little star once you get to know it. The star is called “fish-mouth.” Well, that’s the English translation of the Arabic word. Its real name is Fomalhaut (foe-ma-low), usually pronounced foe-mal-howt here in America. It marks the mouth of Piscis Austrinus, the southern fish, and as you may have guessed, it’s south of the better known zodiacal constellation of Pisces the fish, which has no bright stars at all. By mid-evening you’ll find Fomalhaut due south.
Thu Oct 24, 2019 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
Fri Oct 25, 2019 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.