I Can’t Sleep - Glaciers | Soothing Bedtime Reading for Sleep

Episode Date: October 27, 2024

Unwind with this calm bedtime reading about glaciers, the immense rivers of ice that shape landscapes and hold stories of Earth’s past. Benjamin’s gentle narration explores how glaciers form, move, and influence the world around us, all in a peaceful and steady cadence. With fact-filled storytelling—no whispers, no hypnosis—this episode is designed to ease insomnia, reduce stress, and quiet restless thoughts. Perfect for helping you let go of the day and drift into deep rest. Press play, relax, and imagine the slow, calming flow of glaciers. Want More? Request a Topic: https://www.icantsleeppodcast.com/request-a-topic Ad-Free Episodes: https://icantsleep.supportingcast.fm/ Shop Sleep-Friendly Products: https://www.icantsleeppodcast.com/sponsors Join the Discussion on Discord: https://discord.gg/myhGhVUhn7 This content is derived from the Wikipedia article on Glaciers, available under the Creative Commons Attribution-ShareAlike (CC BY-SA) license. Read the full article: Wikipedia – Glaciers. Happy sleeping! Learn more about your ad choices. Visit megaphone.fm/adchoices

You're listening to a Glassbox media podcast. What if I told you that most of the modern day self-help advice you've been hearing could actually make you worse? The key to a better life isn't about feel-good gimmicks that sound catchy. The Mentally Stronger Podcast gives you access to a licensed therapist who shares science-backed tools that will actually change your life. Hi, I'm Amy Morin, psychotherapist, mental strength trainer, and international best-selling author. In each episode, we cover research-back strategies, like how to stop relying on willpower and start creating habits for lasting change. And the five mental strength-building exercises you can do from your couch. I also speak to world-class experts like Dr. Nicole Kane, who shares how to permanently heal anxiety by addressing the root cause.

With over 200 episodes in our catalog, this podcast is for you if you're ready to crush self-doubt, conquer challenges, become stronger than ever with therapist-approved strategies that can change your life. Listen to Mentally Stronger with Therapist Amy Morin, wherever you get your podcasts. Welcome to the I Can't Sleep Podcast, where I read random articles from across the web to bore you to sleep with my soothing voice. I'm your host, Benjamin Boster, and today's episode is from a Wikipedia article titled Glacier. A Glacier is a persistent body of dense ice, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries.

It acquires distinguishing features such as crevices and syrochs, as it slowly flows and deforms and distresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms, such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.

On earth, 99% of glacial ice is contained within vast ice sheets, also known as Continental glaciers, in the polar regions, but glaciers may be found in mountain ranges on every, continent other than the Australian mainland, including Oceania's high-latitude Oceanic Island countries, such as New Zealand. Between latitudes 35 degrees north and 35 degrees south, glaciers occur only in the Himalayas, Andes, and a few high mountains in East Africa, Mexico, New Guinea, and Ansarqu and Iran. With more than 7,000 known glaciers, Pakistan has a lot of

more glacial ice than any other country outside the polar regions. Glaciers cover about 10% of Earth's land surface. Continental glaciers cover nearly 13 million square kilometers, or about 98% of Antarctica's 13.2 million square kilometers, with an average thickness of ice 2100 meters. Greenland and Patagonia also have huge expanses of continental glaciers. The volume of glaciers, not including the ice sheets of Antarctica and Greenland, has been estimated at 170,000 cubic kilometers.

Glacial ice is the largest reservoir of fresh water on Earth, holding with ice sheets about 69% of the world's freshwater. Many glaciers from temperate, alpine, and seasonal polar climates store water as ice during the colder seasons, and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source that is especially important for plants, animals, and human uses when other sources may be scanned. However, with high altitude and Antarctic environments,

the seasonal temperature difference is often not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, changes, e.g. precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level. A large piece of compressed ice or a glacier appears blue, as large quantities of water appear blue, because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the created

ice's density. The word glacier is a lone word from French and goes back to Franco-Provincial to the vulgar Latin glaciarium, derived from the late Latin glacial, and ultimately Latin glaces, meaning ice. The processes and features caused by or related to glaciers are referred to as glacial. The process of glacier establishment, growth, and flow is called glaciation. The corresponding area of study is called glaciology. Glaciers are important components of a global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, and behavior.

and behavior. Alpine glaciers form on the crests and slopes of mountains. A glacier that fills the valley is called a valley glacier, or alternatively, an alpine glacier or mountain glacier. A large body of glacial ice astride a mountain, mountain range, or volcano, is termed an ice cap or ice field. Ice caps have an area less than 50,000 kilometers squared by definition. Glacial bodies larger than 50,000 square kilometers are called ice sheets or continental glaciers. Several kilometers deep, they obscure the underlying topography. Only nunitaks protrude from their surfaces. The only extant ice sheets are the two that cover most of Antarctica and Greenland.

They contain vast quantities of freshwater, enough that have both melted global sea levels, would rise by over 70 meters. Portions of an ice sheet or cap that extend into water are called ice shelves. They tend to be thin with limited slopes and reduced velocities. Narrow, fast-moving sections of an ice sheet are called ice streams. In Antarctica, many ice streams drain into large ice shelves. Some drain directly into the sea, often with an ice tongue, like, Mertz Glacier. Tidewater glaciers are glaciers that terminate in the sea, including most glaciers

flowing from Greenland, Antarctica, Baffin, Devon, and Ellesmere Islands in Canada, southeast Alaska, and the northern and southern Patagonian ice fields. As the ice reaches the sea, pieces break off for cave, forming icebergs. Most tide water glaciers cave above sea level, which often results in a tremendous impact as the iceberg strikes the water. Tide water glaciers undergo centuries-long cycles of advance and retreat that are much less affected

by climate change than other glaciers. Thermally, a temperate glacier is at a melting point throughout the year, from its surface to its base. The ice of a polar glacier is also below the freezing threshold from the surface to its base, although the surface snowpack may experience seasonal melting. A subpolar glacier includes both temperate and polar ice, depending on the depth beneath the surface and position along the length of a glacier. In a similar way, the thermal regime of a glacier is often described by its basal temperature.

A cold-based glacier is below freezing at the ice-ground interface and is thus frozen to the underlying substrate. A warm-based glacier is above or at freezing at the interface and is able to slide at this contact. This contrast is thought to a large extent to govern the ability of a glacier to effectively erode its bed, as ice promotes plucking at rock from the surface below. Glaciers which are partly cold-based and partly warm-based are known as polythermal. Glaciers form where the accumulation of snow and ice succeeds ablation. A glacier usually originates from a circland form, alternatively known as a quarry or as a CWM,

a typically armchair-shaped geological feature, such as the depression between mountains enclosed by a reeds, which collects and compresses through gravity the snow that falls into it. This snow accumulates and the weight of the snow falling above compacts it, forming nevay, granular snow. Further crushing of the individual snowflakes and squeezing the air from the snow turns it into glacial ice. This glacial ice will fill the cirque until it overflows through a geological weakness or vacancy. such as a gap between two mountains.

When the mass of snow and ice reaches sufficient thickness, it begins to move by a combination of surface slope, gravity, and pressure. On steeper slopes, this can occur with as little as 15 meters of snow ice. In temperate glaciers, snow repeatedly freezes and thaws, changing into granular ice called fern. Under the pressure of the layers of ice and snow above it, this granular ice fuses into denser fern. Over a period of years, layers of fern undergo further compaction and become glacial ice.

Glacier ice is slightly more dense than ice formed from frozen water because glacier ice contains fewer trapped air bubbles. Glacier ice has a distinctive blue tint because it absorbs some red light due to an overtone of the infrared OH stretching mode of the water molecule. Liquid water appears blue for the same reason. The blue of glacier ice is sometimes misattributed to rarely scattering of bubbles in the ice. A glacier originates at a location called its glacier head, and terminates at its glacier foot, snout, or terminus.

Glaciers are broken into zones based on surface snowpack and melt conditions. The ablation zone is a region where there is a net loss and glacier mass. The upper part of a glacier where accumulation exceeds ablation is called the accumulation zone. The equilibrium line separates the ablation zone and the accumulation zone. It is a contour where the amount of new snow gained by accumulation is equal to the amount of ice loss through ablation. In general, the accumulation zone, zone accounts for 60 to 70% of a glacier's surface area, more if the glacier calves icebergs. Ice in the accumulation zone is deep enough to exert a downward force that erodes underlying rock.

After a glacier melts, it often leaves behind a bowl or amphitheater-shaped depression that ranges in size from large basins like the Great Lakes to smaller mountain depressions known as The accumulation zone can be subdivided based on its melt conditions. 1. The dry snow zone is a region where no melt occurs, even in the summer, and the snowpack remains dry. 2. The percolation zone is an area with some surface melt, causing melt water to percolate into the snowpack. This zone is often marked by refrozen ice lenses, glands, and layers. The snowpack also never reaches the melting point. 3. Near the equilibrium line on some glaciers, a superimposed ice zone develops.

This zone is where meltwater refreezes as a cold layer in the glacier, forming a continuous mass of ice. The wet snow zone is the region where all of the snow deposited since the end of the previous summer has been raised to 0 degrees Celsius. The health of a glacier is usually assessed by determining the glacier mass balance or observing terminus behavior. Healthy glaciers have large accumulation zones. More than 60% of their area is snow covered at the end of the melt season, and they have a terminus with a vigorous flow. Following the little ice ages end around 1850, glaciers around the earth have retreated substantially.

A slight cooling led to the advance of many alpine glaciers between 1950 and 1985, but since 1985, glacier retreat and mass loss has become larger and increasingly ubiquitous. Glaciers moved downhill by the force of gravity and the internal deformation of ice. At the molecular level, ice consists of stacked layers of molecules with relatively weak bonds between layers. the amount of strain deformation is proportional to the stress being applied, ice will act as an elastic solid. Ice needs to be at least 30 meters thick to even start flowing, but once its thickness exceeds about 50 meters, stress on the layer above will exceed the interlayer binding strength, and then it'll move faster than the layer below. This means that small amounts

of stress can result in a large amount of strain, causing the deformation to become a plastic flow rather than elastic. Then the glacier will begin to deform under its own weight and flow across the landscape. The lowest velocities are near the base of the glacier and along valley sides where friction acts against flow, causing the most deformation. Velocity increases inward toward the center line and upward as the amount of deformation decreases. The highest flow velocities are found at the surface, representing the sum of the velocities of all the layers below. Because ice can flow faster where it is thicker,

the rate of glacier-induced erosion is directly proportional to the thickness of overlying ice. Consequently, pre-glacial low hollows will be deepened and pre-existing topography will be amplified by glacial action, while Nunatogs, which protrude above ice sheets, barely erode at all. Erosion has been estimated as 5 meters per 1.2 million years. This explains, for example, the deep profile of fjords, which can reach a kilometer in depth as ice is topographically steered into them.

The extension of fjords inland increases the rate of ice sheet thinning since they are the principal conduits for draining ice sheets. It also makes the ice sheets more sensitive to change in climate in the ocean. Although evidence in favor of glacial flow was known by the early 19th century, other theories of glacial motion were advanced, such as the idea that melt water, refreezing inside glaciers, caused the glacier to dilate and extend its length. As it became clear that glaciers behaved to some degree as if the ice were a viscous fluid, it was argued that regalation or the melting and refreezing of ice at a temperature lowered by the pressure on the ice inside the glacier was what allowed the ice to deform and flow.

James Forbes came up with the essentially correct explanation in the 18th. 40s, although it was several decades before it was fully accepted. The top 50 meters of a glacier are rigid because they are under low pressure. This upper section is known as the fracture zone and moves mostly as a single unit over the plastic flowing lower section. When a glacier moves through irregular terrain, cracks called crevices develop in the fracture zone. form because of differences in glacier velocity. If two rigid sections of a glacier move at different speeds or directions, sheer forces cause them to break apart, opening a crevice. Crevices are seldom

more than 46 meters deep, but in some cases can be at least 300 meters deep. Beneath this point, the plasticity of the ice prevents the formation of cracks. Intersection. Crevices can create isolated peaks in the ice called Syracs. Crevices can form in several different ways. Transverse crevices are transverse to flow and form where steeper slopes cause a glacier to accelerate. Longitudinal crevices form semi-parallel to flow where a glacier expands laterally. Marginal crevices form near the edge of the glacier. edge of the glacier, caused by the reduction in speed caused by friction of the valley walls.

Marginal crevices are largely transverse to flow. Moving glacier ice can sometimes separate from stagnant ice above, forming a berkshren. Birxeruns resemble crevices, but are singular features at a glacier's margins. make travel over glaciers hazardous, especially when they are hidden by fragile snow bridges. Below the equilibrium line, glacier meltwater is concentrated in stream channels. Meltwater can pool in proglacial lakes on top of a glacier or descend into the depths of a glacier via moulins. Streams within or beneath a glacier flow in glacial or subglacial tunnels. These tunnels sometimes re-emerge at the glacier surface.

Most of the important processes controlling glacial motion occur in the ice bed contact, even though it is only a few meters thick. The bed's temperature, roughness, and softness define basal sheer stress, which in turn defines whether movement of the glacier will be accommodated by motion in the sediments, or if it will be able to slide. A soft bed with high porosity and low poor fluid pressure

allows a glacier to move by sediment sliding. The base of the glacier may even remain frozen to the bed where the underlying sediment slips underneath it, like a tube of toothpaste. A hard bed cannot deform in this way. Therefore, the only way for hard-based glaciers to move is by basal sliding, where meltwater forms between,

the ice and the bed itself. Whether a bed is hard or soft depends on the porosity and poor pressure. Higher porosity decreases the sediment strength. Porosity may vary through a range of methods. Movement of the overlying glacier may cause the bed to undergo dilatency. The resulting shape change reorganizes blocks. This reorganizes closely packed blocks. closely packed blocks, a little like neatly folded, tightly packed clothes in a suitcase,

into a messy jumble, just as clothes never fit back in, when thrown in in a disordered fashion. This increases the porosity. Unless water is added, this will necessarily reduce the poor pressure, as the poor fluids have more space to occupy. Pressure may cause compaction and consolidation of underlying sediments. Since water is relatively incompressible, this is easier when the poor space is filled with vapor. Any water must be removed to permit compression. In soils, this is an irreversible process. Sediment degradation by abrasion and fracture decreases the size of particles,

which tends to decrease poor space. However, the motion of the particles may disorder the sediment with the opposite effect. These processes also generate heat. Bed softness may vary in space or time and changes dramatically from glacier to glacier. An important factor is the underlying geology. Glacial speeds tend to differ more when they change bedrock

than when the gradient changes. Further, bedrock roughness can also act to slow glacial motion. The roughness of the bed is a measure of how many boulders and obstacles protrude into the overlying ice. Ice flows around these obstacles by melting under the high pressure on their Stoss side. The resultant meltwater is then forced into the cavity arising in their lee side, where it refreezes. As well as affecting the sediment stress, fluid pressure can affect the friction between the glacier and the bed. High fluid pressure provides a buoyancy force upwards on the glacier,

reducing the friction at its base. Glaciers may also move by basal sliding where the base of the glacier is lubricated by the presence of liquid water, reducing basal shear stress and allowing the glacier to slide over the terrain on which it sits. melt water may be produced by pressure-induced melting, friction, or geothermal heat. The more variable the amount of melting at surface of a glacier, that faster the ice will flow.

Basel sliding is dominant in temperate or warm-based glaciers. The presence of basal melt water depends on both bed temperature and other factors. For instance, the melting point of water, decreases under pressure, meaning that water melts at a lower temperature under thicker glaciers. This acts as a double whammy because thicker glaciers have a lower heat conductance, meaning that the basal temperature is also likely to be higher. Bed temperature tends to vary in a cyclic fashion. A cool bed has a high strength reducing the speed of the glacier.

This increases the rate of accumulation, since newly fallen snow is not transported away. The speed of glacial displacement is partly determined by friction. Friction makes the ice at the bottom of the glacier move more slowly than ice at the top. In alpine glaciers, friction is also generated at the valley's sidewalls, which slows the edges relative to the center. Mean glacial speed varies greatly, but is typically around one meter per day. There may be no motion in stagnant areas. For example, in parts of Alaska, trees can establish themselves on surface sediment deposits.

In other cases, glaciers can move as fast as 20 to 30 meters per day. Glacial speed is affected by factors such as slope, ice thickness, snow, No fall, longitudinal confinement, basal temperature, melt water production, and bed hardness. A few glaciers have periods of very rapid advancement called surges. These glaciers exhibit normal movement until suddenly they accelerate, then turn to their previous movement state. These surges may be caused by the failure of the underlying bedrock, the pooling of meltwater at the base of the glacier, perhaps delivered from a superglacial lake, or the simple accumulation

of mass beyond a critical tipping point. Temporary rates up to 90 meters per day have occurred when increased temperature or overlying pressure caused bottom ice to meld, and water to accumulate beneath a glacier. In glaciated areas where the glacier moves faster than one kilometer per year, glacial earthquakes occur. These are large-scale earthquakes that have seismic magnitudes as high as 6.1. The number of glacial earthquakes in Greenland peaks every year in July, August, and September, and increased rapidly in the 1990s and 2000s. In a study using data from January 1983 through October 2005,

more events were detected every year since 2002 and twice as many events were recorded in 2005 as there were in any other year