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03/31/2004
Extremes
Have I become jaded? Or is it time to go home? I was finishing
my early morning walk on the beach the other day and was
thinking that there hadn’t really been anything interesting for a
couple of days. No unusual shells, no dolphins, no moon to light
the way and no particular “catch of the day”. One day last week,
the “catch” was scores of sea urchins washed up over about a
half mile length of the beach. Two days later, I saw not a single
urchin. Another day, the catch was coconuts, about 20 of them
lined up along a quarter of mile length of the beach. Another
day, it was about a dozen oranges that had obviously been at sea
for some time based on their weathered condition.
While thinking about the lack of anything special, I realized there
was a catch that day. It was Bud, Miller and Coors Lite, or at
least the 15 or so cans that were definitely not washed up from
the sea but left on the beach from the day before. Spring Break
touches Marco, if only lightly. One of the features of Spring
Break in more popular locales is the presence of lots of “hard
body eye candy”, a sexist phrase I quote from an article in the
Naples Daily News. In the early morning hours I frequent the
beach, aside from an occasional comely young woman running,
there is certainly no plethora of this type of “candy”.
This past week, the clarity of the nighttime skies over Southwest
Florida has been a definite plus. Without the light pollution we
have back home in the metropolitan New York area, we can
actually see the stars. I’ve gone out to observe the unusual
lineup of the five planets Mercury, Venus, Mars, Saturn, Jupiter
and the moon that has been visible this past week. Mars
continues in the headlines, with more evidence for water from
one of the rovers exploring an area that scientists say is the bed
of a former body of brackish water.
While I think I identified four of the planets properly, I couldn’t
see Mercury. When it comes to planets, it seems that Mercury
hasn’t received its proper share of attention. Its proximity to the
sun makes it difficult to study with Earth-bound telescopes. And
the operators of the Hubble Space Telescope studiously avoid
pointing its lens at Mercury for fear of “frying” the instrument
with light from the sun.
I hadn’t realized what a weird place Mercury is until I read an
article by Fred Guterl in the April 2004 issue of Discover
magazine. The article was spurred by NASA’s forthcoming
“Messenger” mission to Mercury scheduled for launching in
May, at least at the time of writing of the article. If all goes well,
the Messenger spacecraft will go into orbit around Mercury but it
will be a while before we’ll know whether the mission is a
success. The craft won’t go into orbit around Mercury until
2009!
What drew my attention in the article was a statement that there
may be water on Mercury. This seems highly unlikely, given
how close it is to the sun. But let’s take a look at the planet more
closely, starting with the lengths of a Mercurian day and year.
Mercury zips around the sun in only 88 Earth days compared to
our 365 days for a complete orbit. However, Mercury rotates
much more slowly than we do. It takes nearly 59 Earth days for
one rotation of the planet. This combination yields a weird
result. A day (sunrise to sunrise) on Mercury is 176 Earth days
or two full orbits of Mercury around the sun. That means a
Mercury day is twice as long as a Mercury year. Quite a
challenge for any Mercurian calendar makers! (My father was a
salesman for Brown & Bigelow, at the time the world’s largest
calendar company.)
Mercury’s elliptical orbit takes it as close as 29 million miles to
as far as 44 million miles from the sun. Being so close to the
sun, you’d think that if we visited the planet we’d get fried. Not
necessarily. Let’s time our visit to Mercury at its equator when
it’s farthest away from the sun. At dawn, we’d have to wear our
woolies, with the temp being 300 degrees Fahrenheit below zero!
However, by midmorning (22 Earth days later), believe it or not,
the temperature would be the same as it is right now here on
Marco Island, about 80 degrees! Lest we begin to enjoy this
balmy weather too much, we’d better think about departing post
haste. By noon (another 22 Earth days later), we’d be much
closer to the sun and it’s going to be 800 degrees, a bit toasty for
my taste!
Psychologically, we might feel even hotter. At dawn, the sun
appeared twice as big as it does here on Earth but when we came
closer, the sun appeared three times bigger. Even so, without
any significant atmosphere, the sky itself appears as black as
night. And, if somehow we managed to stick around for a full
Mercury day, the sun doesn’t just simply rise in the east and set
in the west. Depending on Mercury’s position at dawn, the sun
rises, hovers a while and then travels in a loop around the sky
before finally setting in the west.
How could there possibly be water under these conditions?
Unlike Earth, Mercury’s orbit is not tilted, which means that
there is no winter or summer. The spacecraft Mariner 10 flew by
Mercury back in 1974 and managed to take pictures of about half
of Mercury’s surface. The South Pole is located in a 110-mile
wide crater, the floor of which never sees sunlight. Radar data
indicate something in the region of a “shiny” nature that could be
water ice. On the other hand, it could be sulfur. I’d be surprised
if it weren’t the latter but, hey, you never know. A nice cold
drink would be most welcome!
I can’t help thinking of the contrast between the conditions on
Mercury and those on the most recently discovered addition to
our solar system. I’m referring to Sedna. Sedna is a strange
object and it seems that there’s some question about what to call
it. I’ve seen it described as a “planetoid” but the March 22
Naples Daily News has an article by Michael Alicea that
describes Sedna as a “worldlet”. Sedna is some 1100 miles in
diameter, a few hundred miles smaller than Pluto in that
dimension. You may recall the controversy still going on as to
whether Pluto should be demoted from a planet to some lesser
category. The discovery of this latest object, not that much
smaller than Pluto, may fuel further attempts to downgrade
Pluto’s status.
The discovery of Sedna is credited to workers at the Palomar
Observatory in California who spotted it barreling along 8 billion
miles from Earth. Needless to say, a whole bunch of telescopes
are now directed Sedna’s way and the photographic archives
have been scoured to spot Sedna’s wanderings in the past. Its
orbit has been determined and it’s a big one. It’s already about
three times farther away than Pluto and its orbit carries it out as
far as 84 billion miles from Earth. That’s far out, to put it mildly,
for a member of our solar system. If Sedna were inhabited, it
might be difficult for its inhabitants to comprehend that they
belonged to a system controlled by the sun. Unlike the situation
on Mercury, to them the sun would appear about the size of a
pinhead!
Apparently, astronomers have also determined that Sedna is red
in color, redder even than Mars. There’s also the possibility that
it may also have a moon. Its discovery has borne out the
predictions of some astronomers that out in the nether reaches of
our solar system there may be bodies that are large, perhaps even
larger than Pluto. Sedna comes close!
Getting back to my beach orbits, yesterday I saw a bird sitting on
the beach and as I walked by it turned its head almost completely
around following my presence. Immediately, I thought I would
write about seeing this owl. Fortunately, there was a bearded
fellow also watching and he identified it as a peregrine falcon.
This morning, I finally did it! Just as Everest has to be climbed
because it’s there, so too does the farthest point of the shore
away from the Marco Island hotels call to be walked to. I
reached “the point” and witnessed a gorgeous Marco sunrise, no
longer jaded.
As I returned from achieving this milestone for the first (and last)
time this year, there was the same bearded fellow following my
footsteps. I thanked him for correcting my misidentification of
the falcon and he remarked that he had seen two bald eagles on
the beach recently. Out on a sand bar near the point were about a
thousand seabirds of all types. We both agreed that this area was
special. Even though I’m no longer jaded, it is indeed time to go
home. Tomorrow, it’s back to New Jersey, where income tax
forms and medical appointments await us. There’s a chance that
I will accept Brian Trumbore’s kind offer that I take a week off.
We’ll see.
Allen F. Bortrum
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