April 2, 2001
"The Star Gazer and the Whale Watcher"
Real Audio
28k
(c) Roger Payne
There are interesting parallels between studying whales and studying stars.
For example, you cannot do an experiment in either field, but must wait for
insights to present themselves to you. So rather than racking their brains
to think of ways to manipulate the unmanipulatable, astronomers and whale
biologists strain their imaginations to think up new ways to observe, and to
extract information from their observations. While visiting the astronomical
observatories on Mauna Kea, a 14,000 foot mountain on the big Island of
Hawaii, I discovered that there are other similarities between these
enterprises. I was in Hawaii to study the humpback whales that gather there
each winter and spring.
Mauna Kea, means white mountain, a name it gets, because it is often
whitened by snow, even though it lies so near the equator. Its base is
15,000 feet below sea level, making it the earth's tallest mountain from
base to summit-higher than Mount Everest. Because its summit presents such
good viewing conditions it is now studded with telescopes, and our best
terrestrial views of the stars come from a mountain about whose feet whales
swim.
The dryness of the air flowing over Mauna Kea is one of the reasons it
offers such superb conditions for viewing the stars. A tropical inversion
keeps moisture well below the summit, and on most days the summit is clear,
even though a cloud carpet billows far below you.
Another reason Mauna Kea has such wonderful viewing conditions is that wind
off the ocean has been blowing over a featureless sea for many miles and so
it is smooth and relatively non-turbulent -free of the mountain waves and
convective cells that disrupt viewing from land. It is as if the ocean made
the wind coherent, combed it into line, so that it carried to land the
pacifying effects of the sea. However, once ashore the frantic, tumultuous,
frenetic, that land gives to all things affects even the wind, and its
healing, soothing hand is shattered like a mirror dropped on stone. If you
put a telescope at the upwind edge of Mauna Kea, it becomes the first object
touched by the prevailing northeast trade winds, and thus, it looks at the
stars through smooth and undisturbed air. How curious that clear views of
the universe depend, in part, on the state of the wind.
At 14,000 feet the cobalt blue of the sky which hides the black through
which the stars swim compares favorably to the cobalt blue of the sea which
hides the black through which the whales swim-each getting its color by
being far from the disturbing influences of land.
Another advantage of being so high is that there is very little atmosphere
to degrade images. At 14,000 feet one is above 40% of the atmosphere. But
this also means one suffers oxygen deprivation. There is evidence that sperm
whales occasionally dive to depths as far below sea level as Mauna Kea rises
above it. To them, the effects of oxygen deprivation at depth, are
presumably similar to those same effects on humans who are at altitude. At
14,000 feet astronomers working on telescopes find they have trouble
thinking clearly. At one point while trying to make what would have been the
simplest of calculations at sea level I was stopped in my tracks. A friend
who tried to come to my rescue fared no better. I was told that astronomers
make all their most important calculations before coming up to the
telescopes.
So it may be that it is not so much the staggering pressures of the abyss,
as it is how much oxygen deprivation a sperm whale can stand-how long it can
hold its breath-that sets the limits on how deep it can dive. At its normal
swimming rate of three miles per hour a sperm whale would require 53 minutes
to reach a depth of 14,000 feet and an equal time to return. If the longest
sperm whale dives last two hours, they would leave just fourteen minutes to
search for food at such depths. Sperm whales must spend very little of their
lives searching for prey at depth, just as oxygen-deprived astronomers must
spend very little of their lives searching for stars at altitude.
I have first hand experience with how unpleasant the working conditions can
be when observing both stars and whales. Both take place under sometimes
grim conditions: in astronomy under the effects of oxygen deprivation (which
can leave you feeling weak and sick and mentally dulled) and in whale
biology under the effects of motion sickness (which can leave you feeling
weak and sick and mentally dulled). In both cases the best strategy is to
come prepared, to endure the conditions when collecting data, and to go home
before you try to think clearly about your results.
This is Roger Payne, speaking to you from home, where, although I can think
clearly, I can no longer see either the universe or the whales.
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