Skywatch for the week of March 29, 2021
Mon Mar 29, 2021 DARKNESS WASTING TIME
By now most of us have recovered from the semi-annual trauma of converting from Standard Time to Daylight saving Time. We’ve run our clocks ahead an hour to compensate for the extra daylight we get early in the morning, thanks to the longer path our sun travels through the sky as we approach summer. This may be a great idea for most folks, but to astronomers who now have to wait an extra hour for the sun to set, this shift is known as darkness wasting time. There has been some talk lately of either abolishing daylight saving time, or abolishing standard time. An article in the Washington Post favored getting rid of Standard Time altogether. That was actually tried back in January 1974; but the extended early morning darkness resulted in a 17% increase in early morning traffic fatalities - so we went back to Standard Time.
Tue Mar 30, 2021 PLANETS AND THE MONTHS OF THE YEAR
The names of the months in our calendar come from ancient Rome, going back about three thousand years in time. Some of these months are named for stars and planets in the heavens. As we come to the end of the month of March, we recognize that it’s named for the planet Mars, also the Roman god of war. Why? Because, as the cold winter gave way to the warmer spring, the Roman army, inspired by Mars, would go out and conquer. The months of May and June are named for two goddesses, Maia and Juno. Juno, the wife of Jupiter, king of the gods, is also the name of a Jovian moon, as well as a robot spacecraft currently in orbit around the giant planet. There is no planet named Maia, but there is the blue giant star Maia which shines in the Pleaides cluster, in myth, a daughter of the god Atlas, who was also the mother of another planet, Mercury. Finally, January is named for Janus, a venerable sky god whose two faces looked both to the past and the future.
Wed Mar 31, 2021 OUT WITH THE RAM
“March comes in like a lion and goes out like a lamb.” This saying is meant to refer to the improving weather in the springtime of the year. But there is also an astronomical connection. At the beginning of March, the constellation Leo the Lion makes its way into the evening sky, appearing in the east after sunset. As the month progresses, Leo appears a little higher in the sky each night, while in the west, many constellations of the late fall and early winter are sinking toward the horizon. By the end of March, one of our winter constellations makes its exit in the western sky. For the past few weeks, the sun has been steadily encroaching on this constellation, as the earth’s revolution has caused the sun to slowly slip eastwards against the background of distant stars. Now the sun is about to pass between us and the constellation Aries the Ram. March comes in with the Lion and goes out with the Ram.
Thu Apr 1, 2021 APRIL FOOLS
Long ago in Europe, and even here, in colonial America, the new year began not on January 1st, but on March 25th, which at that time also marked the beginning of spring. People were so glad winter was over, they partied for about a week, right up through the first day of April. Then came the Gregorian calendar reform in 1582, and France was first to adopt the new system. The French king Charles the 9th decided this was also a good time to move the new year’s celebration from the end of March to the beginning of January, where it is now. But some people just didn’t get it, and continued to observe the new year on April 1st. These people were laughed at, and called “poisson d'avril," or “April Fish” by their more sophisticated countrymen. And this is the origin of our modern April Fool’s Day. No fooling.
Fri Apr 2, 2021 STAR COMPARISONS
In our Milky Way galaxy alone there are an estimated 200 billion stars. They vary in mass and size. Some, like the red supergiant star Betelgeuse, which can be found in the constellation Orion over in the western sky this evening, are as large as the span of the inner solar system. Others, like the blue giant Rigel, also in Orion, are many times hotter and more massive than the sun. Then there are white dwarf stars like the companion star to Sirius in the southwest - only the size of the earth. Smaller still are neutron stars, just a few miles in diameter. And what about black holes, mere pinpoints of super-dense matter. From red and blue giants to yellow suns, white dwarfs, neutron stars and black holes, from solitary suns to multiple star systems, and great globular clusters, each star is unique, possessing within it the secret of its own creation and demise.