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An astronaut on the International Space Station (ISS) recently captured a stunning image of a “sun lens” that turned the sea’s surface into a swirling silver mirror surrounding a pair of Greek islands. The phenomenon of discoloration, which is caused by the sunLight reflected from the still sea directly into the astronaut’s camera, highlights interesting oceanographic effects on and below the water’s surface.
An unidentified member of the Expedition 67 crew took the photo on June 25 using a digital camera pointing out of the window of the International Space Station. The largest area at the center of the image is Milos, a Greek with an area of 58 square miles (151 square kilometers) volcanic The island, and its small uninhabited partner in the west is Antimilos, which has an area of about 3 square miles (8 square kilometers). The silver seas surrounding the islands are the Myrtouan Sea to the northwest of Milos and the Crete Sea to the southwest, both of which are part of the greater Mediterranean. The photo was posted online on September 12 NASA Earth Observatory.
Observers can see sunspots in space where sunlight is reflected off particularly calm seas, or other bodies of water with little or no wave action. It is similar to how light reflects off a standing sea during sunrise or sunset when viewed from Earth, causing a bright streak across the surface; But from space, the line looks like a huge silver patch, often covering several hundred square miles, and seems to move across the ocean like a land Spins.
Wavy lines and eddies in the picture, which cut through the silver surface of the sea like scratches on a mirror, are caused by wind-driven surface currents and ocean currents deep under the surface, as well as by rare phenomena, such as internal waves moving down the surface of the water, and eddies – large systems of currents Rotary circumference. Most of these features usually go unnoticed from space, but because they scatter some sunlight, the features become starkly visible during sunlight.
One of the most striking oceanographic features in the image is the vortex-like vortex to the east of Milos, which looks almost like a massive vortex from above. However, rather than pulling things in like a vortex, these patches of whirlpool water play an important role in maintaining nearby currents that circulate nutrients across the ocean, according to National Oceanic and Atmospheric Administration (NOAA) (Opens in a new tab).
Another noteworthy feature is the long, straight line at the bottom left of the image, which is likely the wake of a ship that was quickly moving across the surface, according to NASA’s Earth Observatory.
But the most interesting feature of the image is arguably the rather innocuous look of the parallel lines off the northeastern coast of Antemelus. These lines, mostly obscured by the cloud surrounding the island, are “internal waves” – huge vertical waves that pass through the waters below the surface. Unlike surface waves, which are primarily driven by ocean currents or strong winds, internal waves are a result of gravity waves (not to be confused with gravitational waves in Spare time).
Gravitational waves pass through the interface or meeting points of two fluids after gravity disrupts the equilibrium between the two, which in this case is caused by tides on Earth. Seas are stratified, meaning that they consist of layers of water with different densities due to changes in temperature and salinity. Thus, gravitational waves can form where these layers meet, creating internal waves within the ocean, accordingly Conversation (Opens in a new tab).
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Normally, internal waves pass through the water without a visible trace. But the umbrellas provide the contrast necessary to illuminate the subtle waves beneath the surface. Other candlelight images captured by astronauts and satellites can also highlight atmospheric gravitational waves that sometimes form where the atmosphere and ocean surface meet, creating massive ripples. As a result, scientists typically use winter clothing to study gravitational waves above and below the surface, according to The Conversation.
Researchers are also using images of winter to track oil spills, because oil slicks at the ocean’s surface reflect less light than water, according to NOAA.
However, for other marine scientists who rely on satellite images to track algal blooms or monitor ocean colour, seedlings can be a nuisance. As a result, these scientists often have to edit solar fingerprints from their satellite images, according to NOAA.
Originally published on Live Science.