Skywatch for the week of August 30, 20201
Mon Aug 30, 2021 LONG MONTH, BLAME CAESAR
August used to be only thirty days long; now it’s 31. You can blame an old Roman emperor for this. Back in 46 BC, our calendar system got a major overhaul when Julius Caesar re-set the beginning of spring to March 25th (it had slid over into May). He also introduced the leap year, which gave an extra day to February every fourth year. Then the dictator was assassinated (probably no connection here,) and eventually his step-son Caesar Augustus took over. To honor dear old dad, Augustus changed the name of the 31-day month Quintillis, and it became July. Then Augustus decided that he ought to have a month named for himself too, and so he changed the next month, Sextillus, re-naming it August. But it had only 30 days, so the emperor tacked on another day to make it just as long as his father’s, and that’s why this month is so long, and that’s also why politicians should never be left in charge of calendars.
Tue Aug 31, 2021 CRASH GO THE COMETS!
On August 31st, 1979, a comet crashed into the sun. Well, crashed is probably not the right word. It’s hard to crash into anything if you’ve been vaporized long before impact. It turns out that a lot of comets have augered into the sun over the years. That’s because the sun’s huge gravity field is powerfully attractive! The comet actually had a name before it was destroyed: Comet Howard-Koomur-Michiels. Not exactly a household name, but that’s the beauty of comets: they’re named after the people who discover them, and that’s typically amateur astronomers who scan the heavens using telescopes with wide fields of view for searching large sections of the sky. Comet Howard-Koomur-Michiels was discovered independently by three amateur astronomers, so their names were attached to it. Of course, the comet no longer exists; as I’d mentioned it got toasted by the sun 41 years ago.
Wed Sep 1, 2021 EDGAR RICE BURROUGHS
The science fantasy writer Edgar Rice Burroughs was born on September 1st, 1875. When Burroughs was just two years old, the planet earth passed Mars at a distance of 35 million miles, which gave astronomers a chance to view the red planet up close. In America, the US Naval Observatory Director, Asaph Hall used a 26 inch refracting telescope to discover the two moons of Mars; while in Italy, the astronomer Giovanni Schiaparelli made sketches of what he called “canali,” that he saw on the Martian surface. The Italian word, “canali,” means, “channel,” which Schiaparelli thought were natural features on Mars. But in America, the word got mistranslated to, “canals,” which are artificial. From that time on, a regular Mars mania swept the world, and in 1912, Burroughs’ novel, “Under the Moons of Mars,” launched his career. Besides his series about John Carter of Mars and other off-world adventures, Burroughs is best known for his Tarzan stories.
Thur Sep 2, 2021 PIONEER 11
In September 1979, Pioneer 11 became the first spacecraft to travel past Saturn. It was launched in 1973, and took over 6 years to cross the billion-mile gap between Earth and Saturn. Along the way Pioneer 11 shot past Jupiter, and used the giant planet's gravity to accelerate – sort of a cosmic version of “crack the whip”. It also almost got its circuits fried by intense electromagnetic radiation that surrounds the giant planets. And Pioneer 11 was first to see Saturn's twisted, outermost F ring. If you’d like to take a look at Saturn and Jupiter tonight, you’ll find them in the southeastern sky after sunset. Jupiter is the very bright star-like object, while Saturn is the dimmer star to the west, that’s to the right, of Jupiter. Even small telescopes can reveal Jupiter’s moons and Saturn’s rings, but although Pioneer 11 is in that same general area of the sky, you can’t see it, even with the most powerful telescope on earth. It’s over 10 billion miles out, in the great beyond.
Fri Sep 3, 2021 INTERSTELLAR VS. INTERGALACTIC
I like science fiction movies, but often the science is bad, like when they talk about how far away things are. Distances started out small; in the 1950’s classic, The Day the Earth Stood Still, Klatuu, an alien, says he traveled 200 million miles. Well, that one’s easy, it can only be Mars. Klaatu says he represents a great many civilizations from other stars in our galaxy. Now the correct term for this is “interstellar,” literally, “between the stars.” But what bad science fiction movies often say is “intergalactic,” meaning, “between galaxies.” And the aliens say things like, “We traveled hundreds of light years from another galaxy so that we could take all your chocolate.” But hundreds of light years still puts you inside our own Milky Way, which is simply immense, 100,000 light years across. To come from another galaxy would be to travel a distance of millions of light years. So let’s forget “intergalactic,” and bring back good old, “interstellar.” And maybe we should hide the chocolate too, just in case.