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The
Silent Landscape
Chapter
Twelve. Dreams of Big Science
Yokahama,
Japan, June 16, 1875, 35o28'N, 139o
38'E to Portsmouth, Great Britain, 50o48'N, 1o
05'W
Home
From
Japan, Challenger headed east into the immensity of the
North Pacific. The dredging hauls were poor, because the
seafloor in that region was rocky and barren. For those
on board this leg of the voyage was as dreary as their voyage
from the Admiralty Islands to Japan. Many had had their
fill of the voyage and none felt this way more keenly than
Herbert Swire: “For nearly one mortal month we have been
at sea without one sight of land and only once chancing
across a ship. I am sick of it...
At
3:00 p.m. on July 27, 1875, Challenger anchored outside
the reef at Honolulu before moving on to Hilo and the Big
Island. There they prepared to climb the volcano Mauna Loa.
Campbell
and Moseley set out at two o'clock in the afternoon of the
day they arrived in Hilo but did not arrive at the hotel
on the rim of Kilauea until 1:30 in the morning. But the
view during the final phases of their ascent was worth it.
“Presently a red glow appears among the clouds on our right,
increases and then the clouds which before had covered it
melt away and Mauna Loa reveals its long, low lying summit
from the center of which a great column of lurid light and
smoke is flaring…”
The
next morning the rest of the party joined them. The hotel
was of a surprisingly high quality despite its location
right on the edge of an active volcano. The plumbing arrangements,
however, perplexed the travelers. A grass hut had been erected
some distance from the hotel over a crack in the lava through
which steam issued. The steam condensed in the grass and,
together with any rain that might have fallen into the grass
roof, ran back into the hut, where it was collected and
stored in tanks. Over the tanks was a hand pump to pump
the warm whiskey-colored water into a bathing tub.
Farther
down the hill was an even more dangerous bathing contraption,
a sulfur-vapor bath...
...As
the sun disappeared behind the rim of the crater they found
themselves standing on the edge of a low cliff, watching
as the dominant colors shifted from black, gray, and white
until a dim crimson glow suffused the drifting clouds of
smoke. Beneath them they saw delicate traceries of red and
realized that only inches below their feet the molten lava
of Hawaii ran in its broken arteries.
They
had arrived at a completely different type of volcano than
they had encountered in the Ring of Fire, for this was the
visible remnant of a 'hotspot'...
Hot
Spot
In the 1960s the new priesthood
of the plate tectonic revolution had to deal with rather
an embarrassing problem. They had explained how new crust
is formed at the mid-ocean ridges and also how it is consumed
at subduction zones But how could they explain the volcanic
activity in the middle of the tectonic plates, far from
the regions where crust was created or destroyed? Nowhere
is this process more active than in the Hawaiian Archipelago
and nowhere is the problem more obvious, because Hawaii
is more than 3,200 kilometers from the nearest plate boundary.
Where do its conspicuous volcanoes come from...?
...J.
Tuzo Wilson reasoned that volcanic islands far from spreading
centers or subduction zones could form only if there was
a localized region where molten magma from the earth's
interior welled up from the center of the earth and heated
the underside of tectonic plates forming localized “hot
spots”. These hot spots would take the form of volcanoes
on the surface. The idea was so radical that when Wilson
put it forward it was rejected by all the major scientific
journals and was eventually published in the relatively
obscure Canadian Journal of Physics.
But
Wilson's idea of hot spots elegantly explained the linear
path of the Hawaiian Island chain from Kauai in the northwest
to Hawaii in the southeast and also presented a testable
hypothesis, always a sign of good science. The most northerly
of the Hawaiian Islands, Kauai, should be both the oldest
and the most heavily eroded, while Hawaii itself should
be the youngest and least eroded. Radiometric dating of
the rocks, as well as the observed degree of erosion on
the islands, agreed with Wilson's hypothesis, so the scientific
community had no choice but to accept that he was right.
Further
research has shown that the Hawaiian Island chain is but
the most recent spoor left by the passage of the Pacific
plate over this mid-Pacific hot spot. Examination of Heezen
and Tharp's map of the northern Pacific shows clearly
a submerged line of extinct volcanoes marching northwestward
through Midway and beyond. Strangely though, at a latitude
of approximately 32oN and a longitude of 171oW, the line
of volcanoes kinks abruptly and heads almost due north
in the form of the Emperor Seamount chain. This suggests
that the Pacific plate changed direction abruptly about
43 million years ago.
Pacific
Exeat
On August 19, 1874, Challenger
weighed anchor and left Hilo, heading south for Tahiti
and the Society Islands
It was also on this leg of the
voyage that tragedy struck the Scientifics. Von Willemoes
Suhm, the young man whom Wyville Thomson recruited in
Edinburgh by and whose membership in the Scientifics
was endorsed by Thomas Henry Huxley, died suddenly of
erysipelas, a bacterial infection of the skin. He was
only 28. Moseley was devastated.
On November 15, 1875, they said
farewell to Juan Fernandez and set sail for Valparaiso,
360 miles distant. That day Captain Thomson issued wine
to all hands to commemorate the third anniversary of
their commission. They arrived in Valparaiso on December
7th and found it a marked contrast to the beauty of
Tahiti.
Challenger left Valparaiso on
December 11th, steaming out of the harbor at daybreak,
and then pausing to calibrate the compass. She spent
the last days of 1875 and the first days of 1876 surveying
in the narrow coves and fjords of South America around
the peninsula of Tres Montes, then further south in
the Messier and Sarmiento channels before steaming down
the Strait of Magellan to avoid the notoriously bad
weather of the west Patagonian coast. All around them
rose the Andes, the southernmost tip of the Ring of
Fire that they had first encountered so long ago on
the other side of that titanic ocean.
From Montevideo Challenger headed
north for Ascension Island, and then the Cape Verde
Islands, where they arrived on April 16, 1876. They
were following the line of the mid-Atlantic Ridge, first
discovered by them four years before, and by mid-May
were passing to the west of the Azores homeward bound.
They were not far from a place that would, a hundred
years later, see spectacular confirmation of Challenger's
discovery.
Black
Ops and Cold War Rocks
The
further exploration of Challenger's first great discovery—the
mid-Atlantic Ridge—reached an important milestone
when humans eventually visited that dreadful region
to see it for themselves during the FAMOUS expedition,
but we should remember that there was an additional
impetus for that effort. This came from another science
program, another dream of “big science,” that also
had its origins in the plate tectonic revolution.
It was a scientific program that is arguably even
more important, if possibly less glamorous, than Project
FAMOUS; a scientific program that had the most mysterious
of origins in the paranoia of the Cold War, the space
race, and the missile gap...
(The
drilling vessels GLOMAR Challenger and JOIDES Resolution,
HMS Challenger's spiritual and scientific succesors)
Arrival
The
weather after the Azores was poor, “with strong
and adverse winds,” as William Spry put it. It was
decided that Challenger would put into Vigo (Portugal)
to coal and this they did on May 20. They did not
linger, because the lure of home was too strong.
Early the next day they were again at sea. “The
weather was still squally and unpleasant,” wrote
Spry, “yet we managed to get round Cape Finisterre;
and now with the wind somewhat fairer, a capital
run was made across the dreaded Bay of Biscay.”
On the evening of the 23rd they saw the light on
Cape Ushant and the next morning gazed through welcome
haze and fog at the soft green lines of Old England.
“Onward we go, sighting the old familiar headland
and landmarks—the Eddystone, the Start, the white
cliffs at Portland and St. Alban's head—until at
last the Needles are in sight…”
They
were home.
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