What is special about Magnetic Hill in Ladakh?

Magnetic Hill located near Leh in Ladakh is a gravity hill alleged to have magnetic properties strong enough to make cars gravitate to the top of the hill at a speed of 20 km/hour with the engines off and interfere with the transmission of passing aircrafts if they fly over it at a lower altitude! In reality, the layout of the surrounding land produces the optical illusion that a very slight downhill slope appears to be an uphill slope. A contributing factor is a completely or mostly obstructed horizon; without a horizon, judging the slope of a surface is difficult as a reliable reference is missing.

This has become a major tourist hub, everyone is fascinated that the hill makes the car look like it’s floating upward. Tourism officials have put up a sign and a marked box on the road where tourists can park their vehicles and witness their car moving at a speed of 20 km/hr. Locals say that the Indian Air Force play it safe and don’t fly around the Magnetic hill. They also say that the helicopters and aircraft flying above the magnetic hill comes within the radius of magnetic hill start to jerk. It is advised to fly at a specific speed and height above the Magnetic Hill to avoid accidents. There are hundreds of other roads and gravity hills like this around the world, in India this phenomenon can be experienced in Tulsishyam, Gujarat as well.

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What beach in the Bahamas has pink sand?

Harbour Island in the Bahamas is like something out of a Barbie dream world almost three miles of a baby-pink sand beach. It gets its rose-coloured hue from foraminifera, single-celled marine organisms whose red shells mix with the beach's white sand, creating its distinct pink colour.

The almost indescribable pale pink color of the sand comes from microscopic coral insects, known as Foraminifera, which have a bright pink or red shell full of holes through which it extends pseudopodia, footings that it uses to attach itself and feed. Foraminifera are among the most abundant single cell organisms in the ocean and play a significant role in the environment. These animals live on the underside of reefs, like the nearby Devil's Backbone, on the sea floors, beneath rocks, and in caves. After the insect dies, the wave action crushes the bodies and washes the remains ashore and mixes it in with the sand and bits of coral. The pink stands out more in the wet sand at the water's edge. Unlike other parts of the world, the sand here is always cool, so you can walk about freely with bare feet.

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What are fulgurites?

Fulgurites are unusual tubes that form when lightning strikes sandy areas. These formations get their name from fulgur, Latin for lightning, and are also called 'fossilised lightning'. Fulgurites resemble roots with a rough surface. However, the inner surface is smooth and glassy, because of the fact that the sand cools rapidly and solidifies. Fulgurites are rare; while lightning strikes the Earth's surface at least a million times each day, these bolts have to be low and powerful enough to melt sand or soil into these shapes. Fulgurites are very fragile as they are hollow. Since they trap air bubbles, old fulgurites are used to study the composition of air in ancient times. A 250-million-year-old fulgurite found in the Sahara desert, for instance, suggests this area of the world was once a fertile area with frequent storms.

Fulgurites are very fragile, as they are hollow and have lots of air spaces. They can get longer than 10 feet, although most are a few inches. Since they trap air bubbles, old fulgurites can be used to study the composition of air in ancient times. Additionally, the number of fulgurites found along with the date formed can provide information on the frequency of lightning.

The Libyan Desert is pure white sand composed of quartz. Fulgurites have been found in that desert. Also discovered were pieces of fused quartz with the clarity of clear glass. Such a piece adorns the mummified body of Tutankhamen. The piece is estimated to have formed 26 million years ago. To form such a piece of glass requires very hot temperatures, hotter than lightning. The most reasonable theory is that this was formed by a high-energy impact of a meteor.

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Which is the world's tallest mountain from base to peak?

Mauna Kea in Hawaii is the world's tallest mountain from base to peak at 32,696 feet. This is 3,661 feet taller than Mount Everest. But since Mauna Kea is half under water, we consider Mount Everest the tallest mountain because it reaches the highest distance above sea level.

Mauna Kea is the only Hawaiian volcano with distinct evidence of glaciation. Similar deposits probably existed on Mauna Loa, but have been covered by later lava flows. Despite Hawaii's tropical location, during several past ice ages a drop of a degree in temperature allowed snow to remain at the volcano's summit through summer, triggering the formation of an ice cap. There are three episodes of glaciation that have been recorded from the last 180,000 years: the P?hakuloa (180–130 ka), W?ihu (80–60 ka) and M?kanaka (40–13 ka) series. These have extensively sculpted the summit, depositing moraines and a circular ring of till and gravel along the volcano's upper flanks. Subglacial eruptions built cinder cones during the M?kanaka glaciation, most of which were heavily gouged by glacial action. The most recent cones were built between 9000 and 4500 years ago, atop the glacial deposits, although one study indicates that the last eruption may have been around 3600 years ago.

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What makes gold so ductile?

Pure gold is so ductile that a single ounce of it can be drawn out into a wire 80 kms long, five microns or five millionths of a metre thick, without breaking. If you did this to all of the existing gold in the world, it would wrap around the earth 11 million times!

Pure gold is also a very soft metal. It will scratch easily, and it’s therefore unsuitable in its pure state for use as coinage or jewellery. For these purposes it’s usually alloyed with other metals such as silver, copper and zinc.

Gold is often found in underground veins of quartz and, less frequently, in other minerals such as pyrite, granite and mica slate. The veins can be anything from half an inch to several feet wide. 80% of the gold that’s produced today is mined from such sources (the rest is ‘alluvial’ gold – see below). Knowing where to mine involves ‘chasing’ the gold-bearing veins on the surface, back underground. It’s been estimated that in the past 500 years, about 100, 000 tonnes of gold have been mined, but even this amount would only fill a cube with 17 m sides. The world’s biggest gold producer is South Africa, where gold mines are sunk over 3,000 metres deep into the earth.

Gold is also often found deposited where a river widens, as well as on the downstream side of large boulders and rocks. The flow of the water slowing down allows any gold to fall to the riverbed under its own weight.

Credit : Open Learn

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