October: The Sky is Falling

October 2011

The Sky is Falling

By Calvin L. Chrisman

October has been a month of meteor showers. Early in the month, the Draconid meteor shower peaked on the evening of the 8th. This is a fairly short shower which was centered over Europe and was somewhat masked by an almost full Moon. The Draconid’s are so named because they appear to originate in the constellation Draco. Harry Potter fans have noticed J.K. Rowling’s interest in celestial names. Harry’s Hogwarts rival, Draco Malfoy, is named after this constellation.

Over last weekend, the Orionid meteor shower (which appears to originate in the constellation Orion) peaked early morning on the 22nd. At this writing, there will still be occasional remnants of this shower visible in the night sky and continuing through the first week of November. We are currently near the new Moon and so it is a good time to see these shooting stars. If you have ever wondered, a meteor is the name of the streak of light you see crossing the sky. The space rock that causes this light show is called a meteoroid and, if it survives a trip through the atmosphere and makes it to the Earth, it is then referred to as a meteorite. The light trail (meteor) that you see is not the space rock (aka meteoroid) burning up; it is a trail of ionized gases caused by the shock wave of the rock passing into the atmosphere at high speed. In the case of the Orionid’s the meteoroids are the remnants of the tail of the famous Halley’s Comet.

Speaking of things burning up in the atmosphere, there has been considerable press recently about spent satellites crashing back to Earth. Last month NASA’s Upper Atmosphere Research Satellite (UARS) came to Earth amid much fanfare and misinterpreted statistics. NASA had reported that there was a one in 3200 chance of any person (not each person) on Earth being hit by parts of UARS and many news outlets reported this as one in 3200 for each person. Since there are about 7 billion people on Earth, the chance of one particular person being hit was one in several trillion. I’m sticking with the Lottery.

It is interesting to realize that man-made debris (a.k.a. space junk) falls from the skies almost every week. There are a lot of spent rockets, satellites, lost tool bags, etc. up there and they come down with little effect. In fact, after fifty years of launches, there have only two credible reports of people being hit by space junk with no significant injuries. This is not surprising given that the Earth is 65% or more covered by water and that most of the land area is lightly inhabited. We can take comfort in this fact as we read reports that the German Rosat will return to Earth this week (and may have done so by this writing).

That very bright star you see rising in the east as the Sun sets is not a star at all. It is Jupiter, currently at opposition. This means that it is directly opposite the Sun from our perspective and is spectacular. It is up all night and is beautiful to the naked eye and through binoculars or a telescope.

Clear Skies!

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