The Dead Sea (Deepest Hypersaline Lake), Between Israel and Jordan

The Dead Sea also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Bank to the west. It lies in the Jordan Rift Valley, and its main tributary is the Jordan River.

The lake's surface is 430.5 meters (1,412 ft) below sea level, making its shores the lowest land-based elevation on Earth. It is 304 m (997 ft) deep, the deepest hyper saline lake in the world. With a salinity of 342 g/kg, or 34.2% (in 2011), it is one of the world's saltiest bodies of water  9.6 times as salty as the ocean  and has a density of 1.24 kg/litre, which makes swimming similar to floating.This salinity makes for a harsh environment in which plants and animals cannot flourish, hence its name. The Dead Sea's main, northern basin is 50 kilometres (31 mi) long and 15 kilometres (9 mi) wide at its widest point.

The Dead Sea has attracted visitors from around the Mediterranean Basin for thousands of years. It was one of the world's first health resorts (for Herod the Great), and it has been the supplier of a wide variety of products, from asphalt for Egyptian mummification to potash for fertilizers. Today, tourists visit the sea on its Israeli, Jordanian and West Bank coastlines. The Palestinian tourism industry has been met with setbacks in developing along the West Bank coast.

The Dead Sea is receding at a swift rate; its surface area today is 605 km2 (234 sq mi), having been 1,050 km2 (410 sq mi) in 1930. The recession of the Dead Sea has begun causing problems, and multiple canal and pipeline proposals, such as the scrapped Red Sea–Dead Sea Water Conveyance project, have been made to reduce its recession. 

The Dead Sea is located at the lowest point on earth, which is thought to be the result of volcanic processes leading to a continuous dropping of land. It is one of the four saltiest bodies of water in the world. These special conditions are an outcome of its extreme geomorphological structure alongside a harsh desert climate. These create constant dramatic changes that form a landscape that is different from any other in the world. Also, the unique mineral content of the air, land, and water in the area is globally renowned for its therapeutic qualities, as is evident in that it has been a health resort for thousands of years.

The Jordan River is the only major water source flowing into the Dead Sea, although there are small perennial springs under and around the Dead Sea, forming pools and quicksand pits along the edges.  There are no outlet streams.

The Mujib River, biblical Arnon, is one of the larger water sources of the Dead Sea other than the Jordan. The Wadi Mujib valley, 420 m below the sea level in the southern part of the Jordan valley, is a biosphere reserve, with an area of 212 km2 (82 sq mi).  Other more substantial sources are Wadi Darajeh (Arabic)/Nahal Dragot (Hebrew), and Nahal Arugot that ends at Ein Gedi. Wadi Hasa is another wadi flowing into the Dead Sea.

There are two contending hypotheses about the origin of the low elevation of the Dead Sea. The older hypothesis is that the Dead Sea lies in a true rift zone, an extension of the Red Sea Rift, or even of the Great Rift Valley of eastern Africa. A more recent hypothesis is that the Dead Sea basin is a consequence of a "step-over" discontinuity along the Dead Sea Transform, creating an extension of the crust with consequent subsidence.

During the late Pliocene-early Pleistocene, around 3.7 million years ago, what is now the valley of the Jordan River, Dead Sea, and the northern Wadi Arabah was repeatedly inundated by waters from the Mediterranean Sea. The waters formed in a narrow, crooked bay that is called by geologists the Sedom Lagoon, which was connected to the sea through what is now the Jezreel Valley. The floods of the valley came and went depending on long-scale changes in the tectonic and climatic conditions.

The Sedom Lagoon extended at its maximum from the Sea of Galilee in the north to somewhere around 50 km (30 mi) south of the current southern end of the Dead Sea, and the subsequent lakes never surpassed this expanse. The Hula Depression was never part of any of these water bodies due to its higher elevation and the high threshold of the Korazim block separating it from the Sea of Galilee basin.

Approximately two million years ago, the land between the Rift Valley and the Mediterranean Sea rose to such an extent that the ocean could no longer flood the area. Thus, the long lagoon became a landlocked lake.

The Dead Sea area has become a location for health research and potential treatment for several reasons. The mineral content of the water, the low content of pollens and other allergens in the atmosphere, the reduced ultraviolet component of solar radiation, and the higher atmospheric pressure at this great depth each may have specific health effects. For example, persons experiencing reduced respiratory function from diseases such as cystic fibrosis seem to benefit from the increased atmospheric pressure.

The region's climate and low elevation have made it a popular center for assessment of putative therapies:

Climatotherapy: Treatment which exploits local climatic features such as temperature, humidity, sunshine, barometric pressure and special atmospheric constituents.

Heliotherapy: Treatment that exploits the biological effects of the sun's radiation

Thalassotherapy: Treatment that exploits bathing in Dead Sea water

Climatotherapy at the Dead Sea may be a therapy for psoriasis by sunbathing for long periods in the area due to its position below sea level and subsequent result that UV rays are partially blocked by the increased thickness of the atmosphere over the Dead Sea.

Rhinosinusitis patients receiving Dead Sea saline nasal irrigation exhibited improved symptom relief compared to standard hypertonic saline spray in one study.

Dead Sea mud pack therapy has been suggested to temporarily relieve pain in patients with osteoarthritis of the knees. According to researchers of the Ben Gurion University of the Negev, treatment with mineral-rich mud compresses can be used to augment conventional medical therapy.

The minerals and salts exclusive to the Dead Sea have been luring visitors for thousands of years, making it the world’s first health resort, dating back to the time of Herod. The high concentration of antiseptic minerals in the mud and salt of the Dead Sea makes it especially beneficial for skin diseases such as psoriasis and vitiligo. Covering the body in mud extracted from the Dead Sea helps the minerals become absorbed into the skin.

There are quite a few mentions of the Dead Sea in the Bible, and it has long been associated with mysticism, wonderment, and religious significance. It has been referenced often to describe the borders of Israel but is also known in its own right. One famous reference is the story of Lot’s wife, which is set in nearby Sodom. The slopes of Mount Sodom are located in the southeast corner of the Dead Sea, and they feature salt formations that look like pillars which are traditionally referred to as Lot’s wife.

Another famous mention is the Dead Sea prophecy, in which the prophet Ezekiel foresees a time when the Dead Sea would be transformed from saline waters that cannot host life, into fresh waters teeming with sea life.

The water level of the Dead Sea has been receding gradually, at an average annual rate of about 110 cm. This causes some concern about whether the Dead Sea is drying up. The natural recession is caused mainly by evaporation under the harsh desert sun, but also because water is no longer being pumped into the Dead Sea from former sources like the Jordan River

One of the main must-do activities on all tourists’ lists is floating in the Dead Sea. Because of the high concentration of salt, the water is much denser than plain fresh water, meaning that our body weight is lighter which causes us to float.

The Eternal Flame Falls, Chestnut Ridge Park in Western, New York

The Eternal Flame Falls is a small waterfall located in the Shale Creek Preserve, a section of Chestnut Ridge Park in Western New York. A small grotto at the waterfall's base emits natural gas, which can be lit to produce a small flame. This flame is visible nearly year round, although it can be extinguished and must occasionally be re-lit. The Eternal Flame Falls were featured in the book Secret Places by Bruce Kershner and in the book What's Weird on Earth.

Eternal Flame Falls is highly dependent on rainfall and melt water. It is usually only flowing in early spring, or after long bouts of heavy rain. It reaches 30 ft high, cascading over sloping shale in two segments. A small grotto, 5 ft up from the creek bed, to the right houses the natural gas spring that can be ignited to create a flame of 4-8 inches in height and believed to be lit thousands of years ago by Native Americans. For a long time, scientists have believed that the fire burns because of gas pockets that rise from the old, extremely hot bedrock made of shale. The rock's high temperatures break down the carbon molecules in the shale, which in turn creates natural gas. When flow is high, the water pours over the grotto, covering the flame and diffusing the light like a lampshade. Eternal Flame Falls is truly one of the most unique waterfalls in the country and one of the few remaining natural areas that we find on our planet. It is said that the falls may be the only one of its kind on the planet.

Once considered an "obscure" attraction in the region, media attention and improvements to the access trail have led to an increased number of visitors. The increased popularity of the falls has led to some negative impacts, such as an increase in litter, vandalism, pollution, and impacts on the surrounding terrain by tourists,but also fueled a successful public protest against a plan to clear a nearby forested area to install a disc golf course in 2012. However, the disc golf course was installed just through the forest area.

Geologists from Indiana University Bloomington and Italy's National Institute of Geophysics and Volcanology studied Eternal Flame Falls in 2013 in an effort to better understand how natural gas emitted from naturally occurring hydrocarbon seeps contribute to greenhouse gases in the atmosphere. They found that the 'macro seep' at Eternal Flame Falls had higher concentrations of ethane and propane (about 35%) than other known natural gas seeps, which typically contain a greater proportion of methane. They estimated that the seep at the falls emits approximately one kilogram (2.2 lb) of methane per day.

The researchers also noted the presence of numerous other 'micro seeps' in the area of the falls. By comparing the gas emitted by these seeps with gas from wells in the area, they determined that the gasses originate from Rhinestreet Shale approximately 400 meters (1,300 ft) below the surface. Tectonic activity likely opened faults in the shale, allowing the gas to reach the surface.

According to one geologist involved in the 2013 study, the seep's apparent source could provide evidence for a previously unknown geologic mechanism by which natural gas is produced within shale. Typically, shale must be hot (around 100 °C for its carbon structures to break down and form smaller natural gas molecules. However, the shale from which Eternal Flame Falls draws its gas is much cooler, in addition to being younger and shallower than typical gas-bearing shale. This may indicate that additional, as yet undemostrated, processes can contribute to the creation of natural gas in shale; one possibility is that a catalyst capable of breaking down shale in cooler conditions is present.

Anechoic Chamber - The World's Quietest Place

Anechoic Chamber is in Building 87 at Microsoft's headquarters in Redmond, Washington, is currently recognized in Guinness World Records as the quietest room in the world, with a measured background noise of -20.35 dBA, 20 decibels below the threshold of human hearing.

If you stand in it for long enough, you start to hear your heartbeat. A ringing in your ears becomes deafening. When you move, your bones make a grinding noise. Eventually you lose your balance, because the absolute lack of reverberation sabotages your spatial awareness. In this room at Microsoft's headquarters in Redmond, Washington, all sound from the outside world is locked out and any sound produced inside is stopped cold. It's called an "anechoic" chamber, because it creates no echo at all. 

The background noise in the room is so low that it approaches the lowest threshold theorized by mathematicians, the absolute zero of sound the next step down is a vacuum, or the absence of sound.

An anechoic chamber (an-echoic meaning "non-reflective, non-echoing, echo-free") is a room designed to completely absorb reflections of either sound or electromagnetic waves. They are also often isolated from waves entering from their surroundings. This combination means that a person or detector exclusively hears direct sounds, in effect simulating being inside an infinitely large room.

Anechoic chambers, a term coined by American acoustics expert Leo Beranek, were initially exclusively used to refer to acoustic anechoic chambers. Recently, the term has been extended to RF anechoic chambers, which eliminate reflection and external noise caused by electromagnetic waves.

Anechoic chambers range from small compartments the size of household microwave ovens to ones as large as aircraft hangars. The size of the chamber depends on the size of the objects and frequency ranges being tested.

The room offers a very rare sensorial experience. "As soon as one enters the room, one immediately feels a strange and unique sensation which is hard to describe," wrote Hundraj Gopal, a speech and hearing scientist and the principal designer of the anechoic chamber at Microsoft.

"Most people find the absence of sound deafening, feel a sense of fullness in the ears, or some ringing. Very faint sounds become clearly audible because the ambient noise is exceptionally low. When you turn your head, you can hear that motion. You can hear yourself breathing and it sounds somewhat loud," he said. In the real world, Gopal explained, our ears are constantly subject to some level of sound, so there is always some air pressure on the ear drums. But upon entering the anechoic room this constant air pressure is gone, since there are no sound reflections from the surrounding walls.

To achieve extreme silence, the room is designed with an onion-like structure that isolates it from the rest of the building and the outside world. It's made of six layers of concrete and steel and it is somewhat disconnected from the surrounding building, because it sits atop an array of vibration damping springs. Inside, fiberglass wedges are mounted on the floor, ceiling and walls to break up sound waves before they have a chance to bounce back into the room. The floor itself is simply a grid of sound-absorbing suspended cables.

"The design, planning and construction took a little over one and a half years," confirmed Gopal.

"I needed a good location on campus where the measured noise levels inside the building were adequately low. I needed to plan the inside of the building so that I could nest the chamber six levels deep. We had to build a special 12" concrete wall encasing the chamber to block out further ambient sound. Careful attention was paid to every detail that could conduct sound from outside to inside the chamber, such as isolating the sprinkler supply pipes and the fire-alarm sensor, or lining the air-supply and return ducts with additional sound absorbing material."

The final result? "The noise level measured inside is -20.3dBA. This means that the ambient noise in the chamber is 20.3dB below the threshold of human hearing." By comparison, one of the quietest sounds that can be heard in a quiet room, calm breathing, clocks in at 10dB.

Microsoft uses the room as an acoustic research lab for several of its products and components, including speakers and microphones. Currently, the company is using the acoustic lab to test Cortana, the company’s voice assistant adding background noise in the room while simultaneously asking questions, to measure and ultimately improve upon performance of Cortana.  

According to Microsoft, the same company who built the previous record-breaking room for Orfield Lab, Eckel Noise Control Technologies, helped create the new room for the company. Microsoft’s Audio Lab itself actually consists of multiple anechoic chambers, with the largest sitting on top of springs in order to keep the amount of outside noise to an absolute minimum. Highly specialized instrumentation from Brüel & Kjær was used to analyze and measure the room. A two-microphone coherent power measurement technique was used to achieve the extremely low ambient noise level measurement.

For more information -Anechoic Chamber

Al-Qarah Mountain (Saudi Arabia)

Al-Qarah Mountain " Jabal Al-Qarah" also known as " Al-shaba'an mountain " located between At-Tuwaitheer village and Al-Qarah village in Al-ahsa at the Eastern Province, Saudi Arabia. This mountain count as one of the most important natural sights in Al-Ahsa and registered in the UNESCO world heritage centre's list at 2018, after the inclusion of Al-Ahsa oasis, it's 15 km away of Al-hofuf east. The mountain has caves , and some of them , such as " Al-Nashab cave " has moderate steady temperature throughout the year.

Al-Qarah mountain named after Al-Qarah village which is belong to. also it's called " Al-Shaba'an " because it's among the palm trees and the rivers , and it has wild high caves which is cold at summer. It's likely that the first inhabitants of Al-Qarah village which has the mountain in it, is pre-Islamic tribe , they were skilled at archery so it's called " Al-Qarah " due to that , but the site landforms tells that the name is referred to "black, small, single, round and high mountain " . moreover , some of history books inform that Al-Qarah mountain is what intended by the name " Al-Mushaqqar " which was mentioned by historians and travelers . therefore , " Hamad Al-jaser " write in his book " Geographical Dictionary of Saudi Arabia - Eastern Province - Section Four " the historian had different opinions about the location of Al-Mushaqqar , so some said it's in Al-Hejaz , or in a valley Eja'a " one of Tae'a mountains " , or in a fort in Al-Bahrain , and the last one is the famous one " While abdul-Khaleq Al-Janbi confirms that Al-Qarah named by that because its south is connected to a huge strange shape and formation hill with vary sizes caves , also , there is a big rock above it and it's carved in wondrous way , in total it has three heads , the first one is to south and look like a woman head , the second one it to the north and look like a man head , the third one between them and look like a lion .this mountain still called " Ra'as Al-Qarah " which is meant by Arabic geographers . " it a divine formation , and human didn't do anything about that " Al-Janbi said in his book . Al-Mushaqqar also was mentioned in the fourth section of " Mou'jam Ma Esta'ajam " - it's a dictionary - for Abu Ubaid Al-Bakry . Ibn Al-E'erabi said " Al-Mushaqqar : a great ancient city , has a fortress in the middle , on a Qarah called Attalah and on the top of it there is a well that makw a hole of Al-Qarah until it get to the ground , so it's absorbed by the ground . All hajer water Exude in that well in its increasing "

The mountain located in Al-Ahsa oasis between four villages which is : Al-Qarah , At-Tuwaitheer , Ad-Dalwah and At-tihemeah

The base area of Al-Qarah mountain is about 14 square kilo meters and consists of reddish colored sedimentary rocks . Also the caves' temperature is semi-steady and moderate along the year and it's about 20 C ° , accompanying with gentle and cool airflow from inside the cave to outside. As well , it's consist of limestone , sandstone , marlstone and siltstones , while the uncovered base of the mountain composed of a thin layer of marlstone topped with layer of Breccias rocks up to 17 m , followed by limestone and sandstone with thickness of 18 m , after that there is a 75 m thickness of sequential layers of grey crumbling sandstone with intermittent layers red marl and marl-alluvial , ends up with a cover of 2 m of limestone. several types of the mountain's caves extend in a form of ribbed grids of cracked ground , while the others are cavities due to chemical weathering , abrasion process and collapses

There is 3 types of caves in Al-Qarah mountain: 1- First type formed due to dissolving and abrasion process of water-soluble rocks , and it is the most common type of limestone caves detected in Saudi Arabia. 2- Second type is a result of collapses of the upper layers because of chemical weathering and abrasion, therefore, lower layers removal, which lead to the formation of wide caves sometimes . the most famous cave of this type is located at the west of the mountain and called Al-Eid cave " Maqarat Al-Eid ", in which the events accompanying with collective wedding take a place there, and it is held annually.

3- Third type formed because of earthquake Fissures and it is a cavernous system that takes a regular form of straight fissures , corridors like . The number of this straight corridors reaches 28 with length of 1.5 km . the most famous cave of this type is Al-Nashab cave which has been invested by Ahsa Tourism company under the name " Land of Civilizations project in Al-Qarah mountain" Each one of the caves has natural characteristics which made the locals take advantages of it based on their usage . so there is cave for the annual collective wedding , and the other for tourists . among the most famous caves in the mountain is : • Bu Saleh ( Al mahdi ) • Al Eid • An Naqa • Al Mua'adhamah • Al Maheub • Al Gairan • Al Nashab • Um Aljamajem

There is a popular belief that the caves in the mountain formed as a result of tides , based on a study was done at 1978 , however , at 2006 other study denied this allegation.

Until 2016 , Al-Qarah was one of the responsibilities of Al ahsa municipality, despite useless repeated attempt to register it at the list of UNESCO world heritage centre , after that , Ahsa Tourism company " Ahsana" invested the mountain to develop it as a modern tourist facility. The tourism projects' cost which was done by the company was about 100 million Saudi Riyal . The project named " Land of Civilizations " , and the project includes preparing the main cave , lighting and leveling its ground. It also includes museum of history of Hajer " Al Ahsa name formerly " , stepped theater , new cafes and shops . This contributed to hold weekly activates ,between cultural evenings , music , arts and visual shows

Some of the caves are characterized by moderate temperatures, which is relatively constant (21-23 °C ) along the year , comparing to the temperature outside the cave or at its outer surface , which gives the feeling that inside the cave is warmer during the winter ,even though it is the same temperature during the summer. The reason of the regular temperature is the thermal insulation of the rocks and the caves are not exposed to direct sun . Also cause of cool airflow is the temperature difference between inside the cave and outside

The mountain was for Bani Muhareb from abdul-Qais till The third century in Hijri Popular beliefs: Habits and traditions Because of the different terrain of each cave , the caves used by the residents in the past and until now like Al-Eid cave for weddings , Al-Nashab cave for tourism and Um Aljamajem cave which recently used for hiking trips since the end of 2019

The caves were used as a place for education before the Formal education , so the teachers were gathering the children at the courtyards of the mountain or at the entrances of the caves, to teach them reading Al-Qur’an One of the habits that were popular in the past , that the people of close villages were burring their special documents in the mountain , so the mountain has a lot of valuable documents and the histories of some families of Al-Ahsa.

The people of the Filipino community in Saudi Arabia call Al-Nashab cave by the name " Judah cave " Because they believe it is the cave that Judas Iscariot committed suicide at it but the source of this belief is unknown and how this community came with it.