Category Geology

What will replace the ISS in 2031?

The International Space Station or ISS is to be deorbited by 2031. Where will it go? Satellites and spacecraft are machines, similar to washing machines and vacuum cleaners. They will not last forever. It doesn’t matter what job they do, whether it’s to observe weather, measure greenhouse gases in the atmosphere, or study the stars. All space machines grow old, wear out and die.

For satellites in Low Earth Orbit (LEO), engineers use the last bit of fuel to slow it down. When the fuel runs out, it falls out of orbit and burns up in the atmosphere. The satellites in very high orbits are sent even further away from Earth, since more fuel is required to bring them down! These satellites are sent into a so-called ‘graveyard orbit, almost 36,000 km above Earth. Space stations and large spacecraft that are in LEO are too large to incinerate entirely on re-entry. So the deorbiting is monitored closely to ensure the debris falls on a remote, uninhabited area. There is an area like this. It’s nicknamed ‘spacecraft cemetery’ and it lies in the middle of the South Pacific Ocean at a spot called Point Nemo. (‘Nemo’ is Latin for ‘nobody’.) Point Nemo is so remote that the ISS will meet its watery grave there. It is considered ideal for dumping space debris as the waters are said to be poor in nutrients and biodiversity. No one has really studied the marine life or lack of it in Point Nemo. Environmentalists fear that in addition to the space junk already present in Point Nemo, the ISS debris will add tons of experimental equipment, materials and even traces of altered human DNA.  

WHAT ARE STROMATOLITES?

Primitive life forms may have first appeared on Earth about 3800 million years ago. These bacteria lived in the oceans and built up solid mats of calcium carbonate, also known as lime. The deposits from the bacteria are known as stromatolites.

Stromatolites are living fossils and the oldest living lifeforms on our planet. The name derives from the Greek, stroma, meaning “mattress”, and lithos, meaning “rock”. Stromatolite literally means “layered rock”. The existence of these ancient rocks extends three-quarters of the way back to the origins of the Solar System.

With a citizen scientist’s understanding, stromatolites are stony structures built by colonies of microscopic photosynthesising organisms called cyanobacteria. As sediment layered in shallow water, bacteria grew over it, binding the sedimentary particles and building layer upon millimetre layer until the layers became mounds. Their empire-building brought with it their most important role in Earth’s history. They breathed. Using the sun to harness energy, they produced and built up the oxygen content of the Earth’s atmosphere to about 20%, giving the kiss of life to all that was to evolve.

Living stromatolites are found in only a few salty lagoons or bays on Earth. Western Australia is internationally significant for its variety of stromatolite sites, both living and fossilised. Fossils of the earliest known stromatolites, about 3.5 billion years old, are found about 1,000km north, near Marble Bar in the Pilbara region. With Earth an estimated 4.5 billion years old, it’s staggering to realise we can witness how the world looked at the dawn of time when the continents were forming. Before plants. Before dinosaurs. Before humans.

Credit: bbc.com

Picture credit: Google

What surrounds the Earth?

 

 

Long ago, people believed the sky was a roof that stretched over the earth. Today, we know that a thick layer of air surrounds the earth like the skin on an orange. But unlike an orange skin, the air moves around the earth, and it reaches far above the earth’s surface. This moving cover of air is a mixture of gases called the earth’s atmosphere.

Air covers the earth everywhere. The pull of gravity holds it there. Near the earth, the air is thick, or heavy. Further away from the earth, the air becomes thinner. Furthest away from the earth’s surface, the air thins and disappears altogether. Where this happens is where space begins!

Picture Credit : Google

Who studies the waters?

Many scientists study the ocean, looking into the secrets of the sea. They study how the ocean moves and how it affects the atmosphere. They study the living things in the sea and the shape of the ocean floor.

Scientists who study the ocean are called oceanographers. Sometimes they work aboard ships. Some wear diving suits and air tanks to explore underwater. Others use small submarines. They use underwater cameras to take pictures of the ocean’s floor and the plants and animals that live in the ocean.

Sometimes they use robots to bring up samples of the mud and sand for study. Some scientists study the direction and strength of waves, tides, and currents.

Oceanographers called marine biologists study the plants, fish, and animals that live in the ocean, lakes, and rivers. They keep track of their health and the way they grow.

Oceanographers called seismologists study earthquakes that happen on the ocean floor. One cause of earthquakes is volcano eruptions, so seismologists often keep track of volcanic activity.

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What is underground water called?

Water from Underground

Not all of the earth’s water is in lakes, ponds, rivers, and oceans. A lot of it is beneath your feet – down in the ground.

Rain falls. Snow melts. Much of the water seeps into the ground. It passes through holes and cracks in the soil until it reaches solid rock. The water can’t trickle any further down, so it spreads out, filling every nook and cranny underground.

The top of this underground water is called the water table. When there is a lot of rain, the water soon fills all the open spaces underground. Then the water table gets higher.

In some places, the water table comes all the way to the top of the ground.

Then, water bubbles out and makes a natural fountain called a spring. Sometimes a spring is the start of a river.

Underground water is usually cool and clean and good to drink. People often dig wells to get this water. There is some underground water almost everywhere in the world – even in deserts. But in a desert, the water is often very, very far down underground.

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Why are Lakes important?

You probably know that lakes give us food and drinking water. But did you know that lakes offer transportation and energy sources?

Many lakes are important for fishing. People who live near Lake Titicaca in South America live simply by raising their own food crops and catching fish from the lake, such as trout. Other lakes, like Lake Winnipeg in Canada, support large fishing industries.

Lakes are important for shipping, too. North America’s Great Lakes are connected with each other and to the Atlantic Ocean. Ships from all over the world can use the lakes to bring things to the many large cities around the lakes.

Lake Maracaibo, in northwest Venezuela, the largest lake in South America, has many oil wells in its waters and along its shores. Under the bottom of the Caspian Sea, north of Iran, oil and natural gas have been found.

Finally, lakes are important to wildlife. For example, Lake Baikal in Russia, the deepest lake in the world, is home to many kinds of wildlife found only in that area. These include a fish called the golomyanka and the Baikal seal, one of the few kinds of seals that live in fresh water. Lake Victoria is the largest lake in Africa and the second largest freshwater lake in the world. Flamingos and other birds feed along the edges of the water. Lake Victoria is also known for its many kinds of tropical fish.

Picture Credit : Google