October 2011 Sky from the Keeble Observatory
Years ago (many more than I sometimes like to admit) I had a poster on my college
dorm room wall that said, “Chicken Little Was Right!” This month, I’d like to begin
with three Chicken Little stories.
You know the original, of course. Chicken Little – henceforth CL - is effectively
paranoid (modern interpretation) and believes that something bad is always about
to happen. He runs around proclaiming that the sky is falling, though of course
it is not. Eventually, nobody will listen to him. If the story has a moral (some
versions don’t) it seems to be that we shouldn’t be afraid of things that aren’t
likely to happen.
But, in some ways, CL was right! Last month we watched the news and the sky because
a 6 ½ ton dead satellite was making an unscheduled return to ground. Launched in
1991, decommissioned in 1996, the Upper Atmosphere Research Satellite (UARS) was
finally ending its time in orbit. Out of control and tumbling, so that NASA couldn’t
even say for sure when or where it would enter the atmosphere on its final plunge,
UARS was expected to break up and mostly burn up. Except for a few pieces weighing
up to 300 pounds or so, that is. How could we not know when and where to duck? Finally,
on the 23rd of September, we are told that the satellite’s remains splashed
down in the Pacific Ocean, far from land and far from anybody getting hurt. But,
something that was once in the sky did fall. And there are tens of thousands more
pieces of “space junk” where that one came from!
Of course, sometimes it seems the sky really does fall. On 1908 June 30 a small
asteroid exploded over the Tunguska River valley, in Siberia. The detonation leveled
trees over 40 kilometers away from the explosion. They still looked like toothpicks
scattered on the ground 20 years later.
It is estimated that the explosive yield was equivalent to a 20 megaton bomb. Imagine
the resulting confrontation if that had happened over a major city during the years
of the Cold War. Fortunately, such large impacts are rare, and cities cover an exceedingly
small fraction of the Earth’s surface. We can then take comfort from a recent research
result from NASA’s Wide Field Infrared Explorer (WISE). They found that the population
of asteroids like the one responsible for the Tunguska event is less than previously
thought. Speculation that there might be upwards of 40,000 such Near Earth Asteroids
have given way to the actual observations. There are only about half that number
to worry about.
And then, the falling sky is sometimes a falling theory, though you’d think the
sky was really falling to hear some people. We were recently treated to the announcement
by a group of European scientists that maybe, just maybe, they had evidence of particles
traveling faster than light – something which is supposed to be impossible according
to Einstein’s theory of Special Relativity. The experimenters created a beam of
neutrinos at CERN and aimed it at a detector miles away on the other side of a mountain.
They were very careful with timing and synchronizing computers and measuring the
distance … and the neutrinos arrived early. Relativity is falling! Relativity is
Except, it’s not. Yet. Extraordinary claims require extraordinary proof, so the
experiment will be repeated many times, and by many other observers looking for
the anomalous time of flight. If corrected, then we have the exciting possibility
of reexamining a pillar of modern physics which has withstood every challenge for
over a century. (“Modern” physics means things we’ve learned since 1900!) Stay tuned
– I suspect a systematic error in the experiment will turn up to eliminate the anomaly.
Lunar phases for October: First Quarter was on the 3rd, at 11:15
pm; Full Moon on the 11th, at 10:06 pm; Last Quarter on the 19th,
at 11:30 pm; New Moon on the 26th at 3:56 pm.
For the most part, this is a limited month for planet watchers, unless you like
staying up late or getting up early. Jupiter rises about an hour after sunset early
in October, getting earlier as the month advances. It’s about 40 degrees above the
southwest horizon by sunrise early in the month. By month’s end it will be in predawn
twilight low to the west. Mars is high to the east at dawn early in the month, moving
to a point high above the southern horizon at late October dawn.
Our midmonth view about 2 hours after sunset finds the unfamiliar and faint constellation
Lacerta at zenith. Your eyes will be drawn west to the familiar Summer Triangle.
Deneb in Cygnus is high to the west, about 70 degrees above the horizon. Below is
Vega, the brightest of the three at about 50 degrees. A bit further south but at
about the same altitude you will find Altair. The Big Dipper is low to the north,
just above the horizon. The “house” shape of Cepheus is inverted above the north
star, Polaris. The tipped W shape of Cassiopeia is to the northeast. A turn to the
east finds the Pleiades rising, anticipating their return to winter skies.
If readers have questions about astronomy or science in general that you would like
covered in one of these columns, please feel free to contact me at firstname.lastname@example.org.