November 27, 1995
Location: 64 55' South Latitude x 127 13' West Longitude -- In Transit
Update:
At 2:00 PM local we moved our clocks back to 1:00 PM. Another day, another
time zone. Gaining an hour has almost become a regular part of the day. It
is often said that there are never enough hours in a day. Even at twenty
five hours a day there still does not seem to be enough.
We are on a course of 274 degrees, slightly north of west, following a great
circle course. We have been averaging about 11 knots. The Captain fired up
all four engines today to make some time in the calm seas. We cruised for
about ten hours at 14 knots.
As we inch ever further north, the sun has begun to follow a more
recognizable cycle. At 1:00 AM the sun had descended just ever so slightly
below the horizon. For less than thirty minutes we were teased with a
nearly sunless dusk. It was the closest we had been to experiencing night
in weeks. It was peculiar to look out the portholes on watch and to feel as
though the ship was veiled in a cloak of feeble darkness. The darkness was
fleeting, just a hint of what the future held. I felt closer to home in
that short half hour of dusk. Closer to normalcy. Closer to home.
The clouds could not seem to muster the endurance to dominate the skies
today. Early in the morning, slight breaks in the thick gray blanket that
has held the blue sky hostage for days were glimpsed. A change was
underway. A change to the most glorious evening since we left the
Bransfield Strait. At 11:00 PM the sun was an enormous yellow beacon on the
western horizon. A silver crescent of moon hung delicately to the east in
the pale blue evening sky. The sea was awash in light, reflecting beams in
all directions from its gentle swells.
Taken by surprise again. Mother nature prepared another glorious feast of
light and color just when we least expected, and when we needed it the most.
Many of us just lounged out on the deck, devouring the banquet of sunshine
that had been prepared for us. The sea extended endlessly to the horizon.
Because of the clear sky it seemed that we could see farther than our vision
was capable. The horizon was merely a reference rather than a point of
termination. It seems that on a clear day at sea, you can almost see
forever, and forever is breathtaking. The sea looked a vivid blue. The
waves, a puzzle of motion and form, charm the watcher to seek patterns in
the undulating surface. You can see pictures made in the swell and hear the
waves speak poems as you become enchanted by the call of the sea.
It is easy to forget the power of the ocean when you are part of the calming
spectacle on a sun filled day at sea. There is so much beauty that it
defies you to see anything else. By midnight, the sun was low on the
horizon, full and red, master of the day. I was not sure if we would see
dusk, or merely rush into dawn. I really didn't want to see the day end.
We started collecting geomagnetic data today. When geophysicists study
geomagnetism they are interested variations in the direction and strength of
the magnetic field in rock layers within the crust. We are able to tell the
direction north and south using a compass. The compass is a small magnet
which aligns itself in the magnetic field of the earth. We can think of the
earth as having a huge magnet passing though its center. The south pole of
the magnet is at the north pole of the earth, and the north pole of this
magnet is at the south pole in Antarctica . When our compass points to the
direction of north it is really being attracted by the magnetically opposite
pole in the earths center.
The direction of the magnetic poles is not constant. Sometimes the poles
completely flip directions, sometimes they just change direction a few
degrees. These changes happen over millions of years and are recorded in
the layers of rock that make up the earth's crust.
When new crust is formed from molten rock from within the earth, the iron
atoms in these new rocks align with the magnetic poles of the earth. This
creates a mini magnet in the crust. Usually these magnetic areas are very
large and cover thousands of miles. The direction of the poles and the
strength of these magnetic zones within the crust are dependent upon the
direction and the strength of the earth's magnetic field when the molten
rock cooled.
When there are regions of molten rock close to the surface, or if regions
within the large regions of crust are affected by volcanic activity or plate
motion, small variations in the magnetic field of these areas can occur.
These variations in strength and direction of the magnetic fields are called
magnetic anomalies. Geophysicists are interested in locating these
anomalies because they are indications of changes in the crust due to the
release of stress from the movement of tectonic plates. This is a very
simplified explanation of the theory, but I think it conveys that the
earth's crust is a complex system, and one important characteristic of that
system is geomagnetism.
This earth's crustal system is constantly changing, but at a rate that seems
unimaginably slow. The time scale of the earth is in thousands and millions
of years. Change happens slowly. The evidence of these slow changes are
mountains, valleys, volcanoes, faults, and subtle variations like magnetic
anomalies.
The magnetometer is used to detect these magnetic anomalies. This device is
towed behind the ship and detects variations in the magnetic field. It is
another tool in the geophysicists chest of gadgets for learning about the
earth's crust.
We have found some very interesting formations from the sea beam data.
These features have been quite unexpected. The area of the sea floor over
which we are traveling is very flat with very little variation. The depth
is nearly 5000 meters. Some of these features are over 500 meters high.
They are like single billboards along a long desolate desert highway. They
are sign posts marking change and stress in the earth's crust for the
scientists on board. They are newly found pieces to a scientific puzzle
which still has many holes.
