My Science School

The sheer weight and size of glaciers give them an enormous power to carve out the landscape. Much like mega bulldozers, they crush and grind everything that comes in their way, pushing the debris along until it is deposited in distinctive piles called moraine.

Glaciers are huge masses of ice that move across the land. ?Glaciers? are often called rivers of ice for the way they move down mountainsides and carve valleys. Though climate change is threatening glaciers today, there are still many glaciers changing landscapes around the world through erosion and material deposition. Glacial landforms left behind by glaciers include moraines, drumlins, troughs, aretes, horns and cirques.

There are three distinct ways that glaciers shape the land: 1) erosion 2) transportation and 3) deposition. Erosion picks up material through weathering through plucking and abrasion. That material is then transported as it moves downhill. Sometimes the material is hidden inside or at the base of the glacier, or sometimes it is on top of the glacier, accounting for the dirty color of some glaciers. Those rocks and other transported materials eventually get deposited to a new place as the glacier melts; this leftover material is called glacial till, and it's what forms many of our landscapes today from the last ice age!

Credit: labroots

Picture credit: Google

When they form in the high mountains, these rivers of ice are called alpine glaciers. They flow down through the mountains, cutting and breaking up the rocks, creating sharp peaks, ridges and gouging out unique, U-shaped valleys.

A glacier that is surrounded by mountains is called an alpine or mountain glacier. They are a persistent body of snow that moves under its weight at a slow pace. Alpine glaciers are a sheet of snow that forms over a cirque or high rock basin. The iceberg’s uppermost layer is brittle, but the ice beneath behaves like a plastic substance flowing gently.

The glacier usually forms in a cirque or high rock basin where snow accumulates throughout the year. The most amazing fact about this glacier is that the rate of accumulation at the upper surface balances the rate of evaporation and melting at the lower end.

The glacier begins to occupy a sloping valley situated in between the creeks or steep rock walls. Following that, the accumulation of snow occurs at the upper part of the bowl-shaped depression called a cirque.

The glacial ice starts flowing downwards, slowly abrading and plucking the bedrock. The accumulation of snow that is compacting and recrystallizing is called firn.

The flow then accelerates across the steep rock where the deep crevasses or gaping fractures mark the icefall. The lower part of the glacier denotes ablation. As the ice thins, it evaporates and melts, thereby losing its plasticity. There are chances of developing fissures, as the glacier tries depositing debris at the terminus when it melts.

Credit: EARTHECLIPSE

Picture Credit : Google 

Glaciers are a very important source of fresh water. Melting glacier ice keeps many of Earth's rivers flowing. Glaciers create fertile valleys for farming and their deposits are also rich in resources.

Glaciers are keystones of Life on Earth. As giant freshwater reservoirs, they support the planet’s life systems and influence our day-to-day lives, even for communities who live far away from them. However, glaciers are disappearing.

The disappearance of glaciers makes visible the invisible. It makes tangible the current climate change that can be hard to perceive in other ecosystems. The recent evolution of glaciers found in World Heritage sites paints a true picture of their decline in a warming planet.

A study led by Jean-Baptiste Bosson in 2019 shows that most World Heritage glaciers have lost a significant portion of their mass since 1900; some even completely disappeared, as in Africa or the Alps. The study predicts that glaciers could disappear from almost half of World Heritage sites by 2100 if business-as-usual emissions continue.

Credit: International Union for Conservation of Nature

Picture Credit : Google 

Fjords are very deep, long and narrow inlets with steep sides or sheer cliffs, seen along the coasts of Norway, New Zealand and Canada. A fjord is formed when the sea comes in to fill the U-shaped valley left by a glacier after it has retreated.

A fjord is a long, deep, narrow body of water that reaches far inland. Fjords are often set in a U-shaped valley with steep walls of rock on either side.

Fjords are found mainly in Norway, Chile, New Zealand, Canada, Greenland, and the U.S. state of Alaska. Sognefjorden, a fjord in Norway, is more than 160 kilometers (nearly 100 miles) long.

Fjords were created by glaciers. In the Earth's last ice age, glaciers covered just about everything. Glaciers move very slowly over time, and can greatly alter the landscape once they have moved through an area. This process is called glaciation.

Glaciation carves deep valleys. This is why fjords can be thousands of meters deep. Fjords are usually deepest farther inland, where the glacial force was strongest.

Some features of fjords include coral reefs and rocky islands called skerries.

Some of the largest coral reefs are found at the bottom of fjords in Norway. They are home to several types of fish, plankton and sea anemones. Some coral reefs are also found in New Zealand. Scientists know much less about these deep, cold-water reefs than they do about tropical coral reefs. But they have learned that the living things in cold-water reefs prefer total darkness. Organisms in cold-water reefs have also adapted to life under high pressure. At the bottom of a fjord, the water pressure can be hundreds or even thousands of kilograms per square meter. Few organisms can survive in this cold, dark habitat.

Skerries are also found around fjords. A skerry is a small, rocky island created through glaciation. Most of the Scandinavian coastline is cut into thousands of little blocks of land. These jagged bits of coastline are skerries. The U.S. states of Washington and Alaska also have skerries.

Even though skerries can be hard to get around in a boat, fjords are generally calm and protected. This makes them popular harbors for ships.

Credit:  National Geographic Society

Picture Credit : Google 

Glaciology is the study of natural forms of ice, particularly glaciers, and phenomena related to ice. It includes the study of how glaciers are formed and depleted, how they move, and how they affect the physical landscape, the climate, and living organisms. It is one of the key areas of polar research. It also involves research into glacial history and the reconstruction of past glaciation, thus providing insights into the ice ages. The apparent presence of ice on Mars and Jupiter's moon Europa brings in an extraterrestrial component to the field.

Thus, glaciology is an interdisciplinary earth science, integrating geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on humans adds the fields of human geography and anthropology. A person who studies glaciers is called a glaciologist.

Credit: New World Encyclopedia

Picture Credit : Google 

Glacial ice is a different color from regular ice. It is so blue because the dense ice of the glacier absorbs every other color of the spectrum except blue — so blue is what we see!

It’s Not Just Frozen Water!

Sometimes the glacial ice appears almost turquoise. Its crystalline structure strongly scatters blue light. The ice on a glacier has been there for a really long time and has been compacted down so that its structure is pretty different from the ice you normally see. Glacial ice is a lot different from the frozen water you get out of the freezer.

It’s Not Just Frozen Snow!

Glacial ice is not just frozen compacted snow. There are other things in the ice that make it much different from the ice in your home. Glaciers move through rock and soil as they carve their way down a slope. This means the ice is going to have a lot more ingredients than just water.

Credit: Alaska Satellite Facility

Picture Credit : Google 

Crevasse, fissure or crack in a glacier resulting from stress produced by movement. Crevasses range up to 20 m (65 feet) wide, 45 m (148 feet) deep, and several hundred metres long. Most are named according to their positions with respect to the long axis of the glacier. Thus, there are longitudinal crevasses, which develop in areas of compressive stress; transverse crevasses, which develop in areas of tensile stress and are generally curved downstream; marginal crevasses, which develop when the central area of the glacier moves considerably faster than the outer edges; and bergschrund crevasses, which form between the cirque and glacier head. At the terminus of the glacier many crevasses may intersect each other, forming jagged pinnacles of ice called seracs. Crevasses may be bridged by snow and become hidden, and they may close up when the glacier moves over an area with less gradient.

Credit: Britannica

Picture Credit : Google 

In places high above the snow line, where more snow gathers than melts, it gets tightly packed. New snow falls and buries the old snow, which turns more dense and grainy. This is called firn and the process is called firnification. Layers of firn build up on top of each other and as they get thick and heavy, the grains of firn merge into huge mases of ice. Over time, the tightly compacted ice becomes so heavy and exerts so much pressure that the glacier slowly starts to move and slide downhill.

Glaciers are huge masses of ice that cover the basement rock. They are found only in regions where snow cover is permanent, that is, at the poles and at high altitude.

At low temperatures, snow does not melt. It accumulates and is compacted into ice. This gradual metamorphosis, which can take several decades, results in the formation of an enormous mass of ice, several dozen meters thick--a glacier.

Propelled by its own weight, a mountain glacier may become detached from the rock wall and slide downward. It slowly flows into the valley like a river of ice. As it descends, the glacier picks up rocks and debris, which accumulate in the form of mounds, called moraines.

If the climate warms, the glacier melts. We say that it recedes. It leaves behind a profoundly eroded landscape composed of wide, flat bottom valleys and many lakes.

Credit: Britannica

Picture Credit : Google 

The world's largest glacier is the Lambert glacier in Antarctica, according to the United States Geological Survey. The glacier is more than 60 miles (96 km) wide at its widest point, about 270 miles (435) long, and has been measured to be 8,200 feet (2,500 meters) deep at its center.

Glaciers form when the annual snowfall in a region exceeds the rate at which the snow melts, allowing enormous amounts of snow to accumulate over time. The fallen snow compresses into solid ice under its own weight, forming solid sheets of ice.

And these sheets are in motion. Glaciers flow like very slow-moving rivers, and can stretch over hundreds of miles. The Lambert glacier flows at a rate of about 1,300 to 2,600 feet (400 to 800 meters) each year.

Credit: LIVE SCIENCE

Picture Credit : Google 

Water level on the surface of the oceans rises and falls. These are called tides. Tides are a result of gravitational forces of the Moon and the Sun as well as the centrifugal forces of Earth's spin. The total amount of water does not change; it just rises at one place while receding at the other.

High tides and low tides are caused by the moon. The moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.

As the Earth rotates, your region of Earth passes through both of these bulges each day. When you're in one of the bulges, you experience a high tide. When you're not in one of the bulges, you experience a low tide. This cycle of two high tides and two low tides occurs most days on most of the coastlines of the world.

Tides are really all about gravity, and when we're talking about the daily tides, it's the moon's gravity that's causing them.

As Earth rotates, the moon's gravity pulls on different parts of our planet. Even though the moon only has about 1/100th the mass of Earth, since it's so close to us, it has enough gravity to move things around.

When the moon's gravity pulls on the water in the oceans, however, someone's bound to notice. Water has a much easier time moving around, and the water wants to bulge in the direction of the moon. This is called the tidal force.

Because of the tidal force, the water on the side of the moon always wants to bulge out toward the moon. This bulge is what we call a high tide. As your part of the Earth rotates into this bulge of water, you might experience a high tide.

Credit: SciJinks

Picture Credit : Google 

The word glacier comes from the French word glace, meaning ice. A glacier is a huge, slow-moving mass of ice. Glaciers are generally seen in mountainous regions where temperatures always remain close to freezing and a massive amount of ice accumulates. Forced by the weight of the ice and the pull of gravity, these sheets of ice start moving, almost like a river, although most glaciers move no more than one  centimetre a day.

Glaciers are massive bodies of slowly moving ice. Glaciers form on land, and they are made up of fallen snow that gets compressed into ice over many centuries. They move slowly downward from the pull of gravity.

Most of the world’s glaciers exist in the polar regions, in areas like Greenland, the Canadian Arctic, and Antarctica. Glaciers also can be found closer to the Equator in some mountain regions. The Andes Mountain range in South America contains some of the world’s largest tropical glaciers. About 2 percent of all the water on Earth is frozen in glaciers.

Glaciers can range in age from a couple hundred to thousands of years old. Most glaciers today are remnants of the massive ice sheets that covered Earth during the Ice Age. The Ice Age ended more than 10,000 years ago. During Earth’s history, there have been colder periods—when glaciers formed—and warmer periods—when glaciers melted.

Scientists who study glaciers are called glaciologists. Glaciologists began studying glaciers during the 19th century in order to look for clues about past ice ages. Today, glaciologists study glaciers for clues about global warming. Old photographs and paintings show that glaciers have melted away from mountain regions over time. Indeed, glaciers worldwide have been shrinking—and even disappearing—at an accelerated rate for the past several decades.

Credit: National Geographic Society

Picture Credit : Google 

Who would have thought  that one day many things we read as science fiction and laughed at as merely an overactive  imagination were about to get real. This is all about the advances in science that are surreal and unfolding right before our eyes in the century itself.

Swanky spacesuit

Have you seen Buzz Lightyear (of Toy Story fame) in his smart spacesuit and wondered why astronauts don't get to wear stuff like that? It looks like they were having the very same thoughts because NASA has given its nod for the Z1 Spacesuit. Astronaut suits so far have been painfully difficult to get into and surprisingly, there have been no new variations since 1992! Surely, astronauts like fashionable wear too? The rear entry feature of the Z1 Spacesuit means that an astronaut just has to step inside instead of going  through complicated manoeuvres. It's a pity the suit doesn't have a laser gun and pop-up wings... yet!

Robots in space

The Robonaut programme has produced four humanoid robots that can tackle different jobs with the same speed and ability as humans. While they may look and behave like humans from the waist up, they do not have any legs to make it all the more easy to attach them onto landing modules or rovers. And there are other perks too - they don't need to breathe and better still they don't get bored, ever.

ZAPPP!

Star Wars has made it clear that laser sabres are the bee's knees! Now, scientists are convinced that these are the exact things we need just in case there's an inter-galactic war in the future - chemical lasers and particle beams. This is mostly because lasers have a very long range as they travel at the speed of light. Beware aliens!

Holidaying in space

You don't have to be an astronaut to travel in space. Got $200,000? You could win a trip to space... for a few minutes. An added attraction: commercial spaceships are designed to look much cooler. USA based Virgin Group's subdivision, Virgin Galactic, will be offering these space trips. Early birds get to make the most of this before it gets cheaper and more commonplace.

Moon base

Moon landings are so last century... setting up a moon base is the 'new' news! NASA plans to set up a moon base on the side of the moon facing away from the Earth. The base would come equipped with its own manned craft to explore the moon better. And in the near future, when space missions to Mars become as frequent as seeing solar eclipses, a moon base will be the perfect gateway base.

Mars, we're coming!

Among all the unbelievable science fiction we've read, the most unlikely one seemed to be setting up colonies on another planet. Yet, a Mars colony is very close to becoming a reality. Elon Musk, the owner of the space transport company Space X, has ambitious plans. He wants as many as 80,000 people inhabiting the little red planet by this century. As far-fetched as it sounds, it apparently is quite feasible, at a mere budget of $36 billion. The one way ticket offered to Mars is definitely an out-of-the-world experience for space enthusiasts. However, the keyword to note is 'one way'.

Picture Credit : Google 

At least in principle any load can be moved by a lever. A lever is a rigid uniform rod resting on a fixed point called fulcrum at which point it can rotate freely. The length of the lever from this fulcrum to the load is load arm and the length from fulcrum to the point where effort is applied is the effort arm. The lever is balanced when Effort x effort arm Load x load arm. If the effort arm is 100m and load arm 1m, the effort needed to lift 1000 kg will be just 10 kg. So keeping the effort arm proportionally long one can in priciple lift any load and that is what Archimedes was trying to say by this boastful statement.

Picture Credit : Google 

Earth is the third planet from the Sun in our Solar System. From a distance, it looks like a great, round, blue jewel hanging in the darkness of space. It is blue because three-quarters of its rocky surface is submerged under blue, ocean waters, which shimmer in the light of the Sun.

The way light reflects off air molecules has an effect on the way people see the sky as well as the ocean. When orbiting the Earth, satellites and astronauts see a blue globe due to some of these same properties. The sheer amount of water on Earth makes it appear blue in these instances, but there are other factors as well.

Scattering in the Atmosphere

The atmosphere is predominantly made of two gases, nitrogen and oxygen. These molecules absorb and scatter, or radiate, different kinds of light. Red, yellow and orange light have longer wavelengths that are not affected by as much by atmospheric gases, so they are not absorbed, but blue light is scattered and radiated, creating the blue sky you see every day. That blue light is not as visible from space, but plays a role in the blue color of the Earth. At night, the sunlight no longer is around to interact with the gases, so the sky become black.

Water Coverage

The Earth has many oceans and seas, from the Arctic Ocean to the Southern Ocean. Although there is red-hot heat below the surface of the Earth, the top layer is dominated by water. The oceans cover about 71 percent of the Earth and are blue, while land makes up the other 29 percent and varies in color, from green to tan to white. This gives the Earth the appearance of a blue marble. If the planet consisted mainly of land masses, it would be appear to be a different color completely.

Water Color

Although water covers a large percentage of the Earth, it is important to understand why the water is blue as well. As with the Earth's atmosphere, most of the colors of the light spectrum are absorbed by the water. The water radiates the blue in the spectrum, giving it its blue color. If another color were radiated, say red for instance, the Earth would look red from outer space, like Mars. The land masses of the Earth do not look blue due to this same principle.

Some Contradictions

The Earth only appears blue if you are looking at it from outer space on the side that is being lit by the sun. When you are orbiting the Earth, it will appear black when you orbit around a part of the Earth that is experiencing night. Because there is no sun to create the light, all of the Earth will appear somewhat dark. The stars will be more visible as well during this period. Land masses will appear somewhat dark blue, as there are artificial light sources that illuminate the sky on land.

Credit: Sciencing

Picture credit: Google

Earth's average orbital speed is about 30 kilometers per second. In other units, that's about 19 miles per second, or 67,000 miles per hour, or 110,000 kilometers per hour (110 million meters per hour).

Let's calculate that. First of all we know that in general, the distance you travel equals the speed at which you travel multiplied by the time (duration) of travel. If we reverse that, we get that the average speed is equal to the distance traveled over the time taken.

We also know that the time it takes for the Earth to go once around the Sun is one year. So, in order to know the speed, we just have to figure out the distance traveled by the Earth when it goes once around the Sun. To do that we will assume that the orbit of the Earth is circular (which is not exactly right, it is more like an ellipse, but for our purpose a circle is close enough). So the distance traveled in one year is just the circumference of the circle. (Remember, the circumference of a circle is equal to 2×?×radius.)

The average distance from the Earth to the Sun is about 149,600,000 km. (Astronomers call this an astronomical unit, or AU for short.) Therefore, in one year, the Earth travels a distance of 2×?×(149,600,000 km). This means that the speed is about:

speed = 2×?×(149,600,000 km)/(1 year)

and if we convert that to more meaningful units (knowing that there are, on average, about 365.25 days in a year, and 24 hours per day) we get:

speed = 107,000 km/h (or, if you prefer, 67,000 miles per hour)

So the Earth moves at about 110,000 km/h around the Sun (which is about one thousand times faster than the typical speed of a car on a highway!)

Credit: Ask an Astronomer

Picture credit: Google