Tides

The gravitational pull of the moon and sun has an effect on Earth objects, but none so visible and spectacular as that on water.

The phenomenon of tides is caused by the gravitational forces drawing water from oceans and seas in different directions causing it to rise and ebb. High and low tides fill and empty coastal areas with more prominent effects taking place at the time  of full and new moons, the equinox and supermoons.

Tidal ranges record the difference between high and low tide levels on the shore. The highest tides are recorded at the Bay of Fundy in Canada.

 

 

Deepest Spot on Earth: Challenger Deep in The Mariana Trench

Mount Everest in the Himalayas is the highest mountain peak on Earth, standing tall at 29,000 feet or approximately 5.5 miles from sea level. The Earth's oceans at some points are deeper than the highest mountain peaks. Deep under the oceans run mountain ranges, peaks, valleys and trenches as awesome in scale and variety as those above land.

The deepest known underwater point is Challenger Deep, in the 1500 mile long Mariana Trench which is one of the known deepest and longest underground trenches. Challenger Deep is 7 miles below sea level and can easily submerge Mount Everest.  At this depth, the water pressure is intense and temperatures at sub-zero, beyond the reach of sunlight.



Deep Challenger in Mariana Trench
Kmusser [GFDL , CC-BY-SA-3.0  or CC BY 2.5 ], via Wikimedia Commons

While marine life is found even at these unfathomable depths, it is very difficult for humans to descend there. Till date only two manned expeditions have been made to Challenger Deep.

From Visually

 

The first expedition was made in 1960 and second and most recent expedition, Deep Sea Challenge, was made by Hollywood film maker and undersea explorer James Cameron in collaboration with the National Geographic in 2012.
 

The Color of the Sea

Water is a colourless or rather, a pale blue liquid.

Large water bodies like the oceans and seas get their distinct hues from reflecting the sky.

Algae, plankton, plants and sediments in water among other things, give different water bodies other distinguishing hues such as yellow, green and even red.

Four seas of the world are named after colours - the Black Sea, the Red Sea, the White Sea and the Yellow Sea. The name of the Black Sea refers to the North direction  than the actual colours of its water!

To check out all possible shades of the sea, head over to CITCLOPS or Citizens’ Observatory for Coast and Ocean Optical Monitoring who offer an interesting colour wheel to check out different shades of sea water on their website.



Shades of the Sea
Images from Unsplash