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IntroductionGeorge Lovi, a well-known astronomy lecturer and author who passed away in 1993, once told me this amusing story:
One night, while George was running a public night at the Brooklyn College Observatory in New York, the telescope was pointed right at Venus, which was displaying a delicate crescent shape at the time. Yet, one student gazing through the telescope eyepiece stubbornly insisted that he was really looking at the moon. When George pointed out that the moon wasn't even in the sky, the student replied, "So what? Doesn't a telescope show you things you can't see without it?"
That story got me thinking about a number of popular misconceptions in astronomy. Here's my own personal list of ten, in no particular order:
Why don't most meteor showers "shower?"Slide 2 of 21
Why don't most meteor showers "shower?"When an announcement is made through the news media about an upcoming meteor shower, it likely will conjure up visions in the minds of many of a sky filled with meteors pouring out of the sky like water from a hose.
Unfortunately, in just about all cases, your average meteor shower is a far cry from that. Typically, if you're outside on a clear, dark night you might catch a glimpse of perhaps three to six meteors (popularly called "shooting stars") over the course of an hour's watch.
On certain nights, the hourly rate may be somewhat higher, in which case astronomers would say that a "meteor shower" is in progress. In the middle of August or the middle of December for instance, you might notice that meteors are comparatively plentiful; perhaps coming at a rate of about one per minute. Indeed, these are the times of the two best meteor displays of the year, although it would never occur to you that a "shower" was in progress. [2011 Orionid Meteor Shower Photos]
There are rare occasions, when Earth interacts with a dense trail of dust recently shed by a passing comet, and meteors will seem to literally pour from the sky in a shower-like fashion. Unfortunately, such opportunities are few and far between. On May 31, 2022 however, we just might get a chance to witness a true "storm" of meteors, with potential rates of thousands per hour. On that night, Earth might pass through the dusty debris that was shed by a comet that broke apart into several fragments in 1995.Slide 3 of 21
Can artificial satellites really be seen with the unaided eye?Slide 4 of 21
Can artificial satellites really be seen with the unaided eye?Most definitely! In fact, many people are surprised that an object orbiting hundreds of miles above our heads can be readily seen without the use of binoculars or a telescope. From the launch of the first satellite, Sputnik, in 1957 to the present, the number of satellites in space has grown at a spectacular rate. There are now over 10,000 satellites orbiting the Earth.
British astronomer Desmond King-Hele once noted that a satellite, "looks like a star that has taken leave of its senses and decided to move off to another part of the sky."
If you go out and carefully study the sky near dusk or dawn, the odds are that you should not have to wait more than 15 minutes before you see a satellite now in orbit. Most are too faint to be seen with the unaided eye, but a few hundred are large enough and low enough (100 to 400 miles/160 to 640 kilometers above Earth) to be seen. [Photos: Spotting Satellites & Spaceships from Earth]
Satellites are seen at night because they are illuminated by the sun. A satellite entering the Earth's shadow immediately vanishes from view and pursues an unseen path until it again emerges into full sunlight.
The International Space Station is by far the brightest manmade object traveling around the planet. Orbiting the Earth at an average altitude of 220 miles (355 km), it can appear to move as fast as a high-flying airliner, taking about two to five minutes to cross the sky. It can easily be confused with aircraft lights, though at its brightest the space station can sometimes appear to rival even Venus in brilliance.Slide 5 of 21
Is it hot in July because we're closest to the sun?Slide 6 of 21
Is it hot in July because we're closest to the sun?No! In fact, the Earth is at its farthest point from the sun in early July, and is closest to the sun in early January. The difference in distance from the Earth to the sun between these two extremes is about 3 million miles (5 million km), or 3.3 percent, which makes a difference in radiant heat received by the Earth of nearly 7 percent. [Top 10 Surprising Results of Global Warming]
Thus for the Northern Hemisphere, one would assume that this difference tends to warm the winter and cool the summer. Instead, the large landmasses in the Northern Hemisphere actually work the other way and tend to make the winters colder and summers hotter than those of the Southern Hemisphere.Slide 7 of 21
Why don't comets appear to zoom across the sky?Slide 8 of 21