In conjunction with this, a reader
recently asked the question: “If North and South America weren't connected at
the time Lehi left the Middle East, wouldn't the ocean currents be different
than they are in the illustrations you use (which seem to be based on the
current connected continents)?”
Actually, I believe this reader meant if
“Central America and South America were not connected.” This question has been
asked and answered before, both in previous posts as well as in the books
mentioned on this site, however, it is a legitimate question and one others
might have, so its answer is repeated here again.
In order to do so, we need to understand
what causes the movement and direction of ocean currents when they near a
continental shelf, as well as what causes waves differently at sea than near a
shore.
First of all, waves at sea are
generated by the wind. Small ripples form on the water as the wind blows across
the ocean’s surface. The size of waves depends on three things: 1) The duration of the wind; 2) The strength of the wind, and 3) The fetch, or the distance over water across
which the wind blows.
The longer the wind blows the
bigger the waves; stronger winds mean higher waves; and the greater the fetch, the
bigger the waves. Thus the biggest waves of all occur in the storms that last
the longest with the most energetic winds with hundreds of miles between the
storm at sea and land. Waves do not actually consist of water traveling from
where the wind is blowing all the way to the beach. Instead of moving water,
waves are moving energy that was transferred from the wind to the water. This
energy propagates, or moves, through the ocean to the beach in the form of a
wave. But the water itself is not moving forward as in a current. Instead, the
energy rolls through the water in a circular motion called a wave orbital. The crest of a wave is the top of a wave orbital, and the trough of a wave is the bottom of a wave
orbital. When the waves reach the shore they expend their energy by breaking
and then moving sand and shaping the beach.
Wind-generated waves in the ocean can travel thousands of miles before reaching land. In the Southern Ocean, they do not reach land at all, but continue to circumnavigate the globe
However, waves on shore are
caused from an entirely different source. As waves move towards shore, they
begin to "feel" the ocean floor (as in the diagram above). In a
process known as shoaling, this causes the wave orbitals to flatten as the
bottom shoals (rises). When waves feel the bottom they slow down and bunch
together (decrease their wavelength); but the time between wave crests (period)
does not change. The height of the wave will initially decrease when it feels
bottom, but then will steadily increase until the wave becomes unstable and
breaks near the beach. The water literally falls over because the surface is
traveling faster than the bottom, which is slowed by the rising sea floor.
Waves expend the energy they gained from the wind by transferring that energy
to the beach when they break.
Secondly, all land
surface seen above the ocean surface is nothing more than the top of underwater
rises, mountains, plateaus, etc., that begin beneath the surface in the seabed.
Some of these land masses do not reach the surface, and are called guyots
(plateaus) or seamounts (mountains). If they rise to near the surface, they
will have an impact on the ocean currents that pass over or around them.
A map of the ocean floor shows a variety of topographic features: flat plains, long mountain chains, and deep trenches
The point is, when Panama was below the
surface, the land was still there, just submerged. Consequently, since the main
and fast-moving ocean currents are dependent upon deep water, and the spin of
the earth creates the Coriolis effect, ocean currents tend to move in a
circular pattern, thus we have in the Pacific Ocean, the North Pacific Current (running
clockwise) in the northern hemisphere and the South Pacific Current (running
counter-clockwise) in the southern hemisphere. This southern current circles
outward from the bulk of Peru in South America and turns back down into
Polynesia and outward back across the Pacific toward Indonesia in a continual
circular pattern without reaching Central America.
The “Southern Pacific Gyre" is part of the Earth’s system of rotating ocean currents, bounded by the equator to the north, Australia to the west, the Antarctic Circumpolar Current (Southern Ocean) to the south, and South America to the east. The center of the gyre is the site farthest from any continents and productive ocean regions
The current in question, called
variously the Circumpolar Current, the Antarctic Circumpolar Current, or The
West Wind Drift, is part of the Southern Ocean, and flows uninterrupted around
the planet. When this current, crossing the South Pacific Ocean reaches the
southern area of the South American shelf (below the surface), the northern portion of this current
is slowed and turned northward along the western coast of South America and
becomes the Humboldt (or Peru) Current. The southern half of this current becomes
the Cape Horn Current and continues through the Drake Passage and on into the South
Atlantic Ocean, eventually circling around to south of Africa and south of the
Indian Ocean Gyre.
Now, if the land surface of southern
South America is below the surface somewhere around the 35º South Latitude, but
only a few feet beneath the surface, the shelf would still have the same effect
on the current—causing it to still slam into the submerged land mass and turn
north. The only difference is that more volume of water would pass through the
Drake Passage than now—but the northern part of the current would still turn
northward up along the coast.
Mr. DowDell,
ReplyDeleteI'm reading your "Lehi Never Saw MesoAmerica" and find it fascinating. Thank you. I have a question. In Section II Chapter 1 you state that the world is just 13,000 years old. I'm wondering how you came to that conclusion as you don't cite any scientific studies on the subject. If you have already addressed this question here in your blog I apologize I was not able to find it. Thank you.
Melissa