Sunday, November 6, 2016

Jewels in the ocean


The Bahama Islands are one of the most recognizable places on Earth for astronauts and one of their favorite areas to photograph. The eyes are naturally drawn to the large areas of shallow seas, known as banks, that appear in light blue.
The edge of the Little Bahama Bank in the northern Bahamas is marked by the straight line of a coral reef. White breaking waves appear on the seaward edge of the reef, and the sea floor rapidly deepens north of this line (darker blue on the lower right).
This long-lens view shows all kinds of detail in the shallow water. The brightest swirls are shelly sands molded into sweeping shapes; they give a strong sense of the flow of water moved repeatedly onto and off the bank. The largest sand feature (a U-shape at image center) lies opposite the widest break in the coral reef—where the tidal flow is strongest. A gap in the line of breakers shows the opening.
The small island known as Strangers Cay is 3.6 kilometers (2.25 miles) long, giving some perspective on the large stretches of seafloor affected by the tides on this shallow bank. Other black shapes are the shadows of clouds.
Regular patterns of swells appear in the deeper water (lower right). The quieter, shallow water in the center of the image—protected from the open sea by the reef—was streaked by a brisk northeast wind on the day this photo was taken.

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