About every 76 years, Halley's Comet becomes visible in our night sky for several weeks, and like surely many of you, I vividly recall its most recent return in 1986. Having heard of the famous comet from my 81-year old stargazing mentor, Margaret Willits, in 1954, I was thrilled to finally see it after a three-decade wait.
It was Ms. Willits who ignited my childhood interest in astronomy, but it was seeing Halley's Comet that rekindled the flame that has been burning brightly ever since. While Ms. Willis told me of her excitement at seeing the comet during its 1910 visit, she didn't tell me about the stir it caused at the time.
Comet Halley is one of several comets whose orbits intersect with Earth's orbit. Of course, should Earth and a comet pass through the same place at the same time, there would be a major catastrophe, such as the one believed to have led to the extinction of the dinosaurs -- but fortunately that's quite rare.
However, the intersection of the orbits of Earth and a dozen or so comets does have some interesting consequences, the most common of which are annual meteor showers. Comets leave tiny pieces of dust, ice and rocks scattered along their orbital path. So when Earth, which is orbiting the Sun at the incredible speed of 67,000 miles per hour, passes though the debris-laden path of a comet, friction between the debris and Earth's atmosphere causes bits of debris to burn and glow, producing meteors, those brilliant streaks that flash across the night sky, also called shooting stars.
Twice each year we pass through Halley's path, producing the Eta Aquarid meteor shower in May and the Orionid shower in October.
But when Halley came by in May 1910, the encounter was closer than usual as Earth actually passed through the end of Halley's 24-million mile long tail.
Throughout history comets have elicited fear and dread. They have even been seen as harbingers, if not the causes, of dreadful things like earthquakes, volcano eruptions, wars, epidemics, fires, and even massacres. (Isn't it curious how natural events are so often blamed for human-caused catastrophes?)
When scientists announced that Halley's tail contained traces of poisonous cyanide, though not nearly enough to be of concern, the last part of the message wasn't heard by all. Some panicked while others cashed in on the irrational fears by selling "anti-comet" pills and "comet-protecting gas masks." Of course, Halley's Comet passed uneventfully, only to return 76 years later to help inspire me to begin writing this column.
• Sky Calendar.
May 16 Sun. evening: The crescent Moon is above Venus.
19 Wed. evening: The Moon is below Mars.
20 Thu. evening: The Moon is at 1st quarter.
22 Sat. evening: The Moon is below Saturn.
27 Thu. all night: The full Moon, called Milk Moon, Flower Moon, Corn Moon, and Planting Moon, accompanies Scorpius' reddish star Antares across the sky all night.
June 4 Fri. morning: The Moon is at 3rd quarter.
• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Evening: "Evening star" Venus now dominates the early evening sky in the west; Mars is high in the southwest; Saturn is high in the south. Morning: Jupiter, now rising 3+ hours before sunrise, is well up in the southeast by morning; Mercury is at its best late in the month low in the east at dawn.
Stargazer appears every other week. Paul Derrick is an amateur astronomer who lives in Waco. Contact him at 918 N. 30th, Waco, 76707, (254) 753-6920 or email@example.com. See the Stargazer Web site at stargazerpaul.com.