Category Environtal Studies

How heavy can clouds be?

Clouds are like light fluffy, white cotton candies on the sky. How much could they weigh? Our first guess would be “Since they float in the air, perhaps, close to nothing!” Well, we are wrong. Researchers have calculated that the average cumulus cloud weighs an incredible 5,00,000 kg. That’s a hundred elephants!

Clouds, after all, are made up of water, and water is quite heavy. The density of cumulus clouds is around 0.5 gram of water per cubic metre. A 1 cubic km cloud contains 1 billion cubic metre. Doing the math: 1,000,000,000 x 0.5 = 500,000,000 grams of water droplets in our cloud. That is about 5,00,000 kg or 1.1 million pounds (about 551 tonnes).

So now, the next question is, how does all this massive weight stay afloat in the sky? How come they don’t fall on our heads? Because the air below it is even heavier. That is, the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air.

Picture Credit : Google 

WHY DID IT TAKE SO LONG FOR LIFE TO APPEAR?

Earth’s surface was probably molten for many millions of years after its formation. Life did not exist for the first 400-800 million years, and first began in water after the forming of the oceans.

Life seems to have started on Earth almost as soon as the surface cooled off enough to make it possible. However, complex animal life—everything from insects to fish to humans – took a lot longer to show up. Given that modern animals are a phenomenally diverse group that evolved relatively quickly, why were they so slow to get going?

The answer may be that animals are greedy: they need a lot of oxygen to grow big and complicated. Early Earth didn’t have much oxygen, but microbes changed the chemical content of the atmosphere over time from something alien and poisonous to us into the breathable air we have today. A new paper showed that the oxygen level as recently as 800 million years ago was only a tiny fraction of today’s – far too low to support oxygen-breathers like our ancestors and their relatives.

Life on Earth has always belonged mainly to microorganisms. Clouds are full of microbes; they have been found in deep mines and on the ocean floor. They outnumber and may even outweigh all other forms of life. If all animals vanished, most bacteria would still live on, but if all bacteria disappeared, we would die quickly.

The history of life on Earth reflects this as well. The first single-celled organisms appeared about 3.8 billion years ago, while the first known multi-cellular organisms evolved 2.1 billion years ago. However, these were “primitive” in our human-centric eyes: they didn’t have specialized organs for breathing or eating, much less brains for the wasteful activity we call “thinking”.

Then in the Cambrian era, around 570 million years ago, recognizably complex animal life evolved, including vertebrate ancestors. This change was relatively rapid in evolutionary terms, and a lot of diverse critters came out of it. Thus, something significant must have changed between 2.1 billion years and 570 million years to let animals diversify and complexity.

To explain this great change, scientists consider several possible explanations. One environmental (as opposed to genetic) idea: animals breathe in oxygen, so there needs to be enough oxygen in the air and water. Corals, sponges, and the like require less oxygen than crabs or fish, so oxygen levels limit what sorts of animals can evolve in a particular environment.

Credit: Daily Beast

Picture credit: Google

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 IS THE TIMELINE OF LIFE ON EARTH?

Just as the day is divided into hours, minutes and seconds, geologists divide Earth’s history into time periods. The longest divisions are aeons, which are billions of years long; the shortest are chrons, a few thousand years long. In between come eras, periods, epochs and ages. Scientists divide the last 590 million years into three eras: the Palaeozoic (meaning ‘old life’), Mesozoic (‘middle life’), and Cenozoic (‘new life’).

Humans have only been a species in the most recent chapter of the history of Earth. The Earth was formed 4.6 billion years ago, when the sun in our solar system first formed, creating enough gravitational pull to spin planets into orbit. But how do scientists know how old the Earth is if humans weren’t around back when it was formed? When was life first formed on this planet? And what are the paths that life has taken so far over the course of that existence? This lesson will teach about the ages that make up the history of life on Earth, and explore the many changes and forms life has taken in its time on this planet.

Timeline of Geological Eras

The geological timeline of Earth is nearly identical to the history of life on Earth, apart from the Hadean Era. This is because the geological timeline, or the order of geological events, such as oceans forming, volcanoes erupting, how long deserts lasted, and tectonic plate movement, all happened in sequence with the life that has existed on this planet. The history of both life and the geological timeline is arranged within 5 subgroups, arranged from the largest span of time to the smallest: eons, eras, periods, epochs, and ages. To understand the timeline of life that has existed on Earth, it is important to understand how scientists determine the age of both rocks and the remnants of living things, otherwise known as fossils.

Because humans were not around 4.6 billion years ago to record the beginnings of our planet, scientists must rely on evidence from geological and fossil records in order to determine the relative age of both the planet and the life that exists here. Both the geological timeline and the age of life are determined in much the same way. Modern scientists rely on what is called radioactive dating to determine an accurate and precise age of both rocks and fossils. Radioactive dating measures the rate of decay of an element in a rock or in a fossil. Carbon-14 is typically used when dating fossils because all living things are carbon-based, and the flow of carbon can be tracked through the carbon cycle. For geological objects such as rocks and minerals, Rubidium-87 and Potassium-40 are often used. By knowing how long it takes for molecules in an object to decay, scientists can calculate when the object’s half-life is. The half-life of an object refers to the amount of time it would take for half of an amount of a substance to radioactively decay, or break down. If the half-life of an object is known, it is possible to calculate when the object was first created, when no decay is evident.

Credit: study.com

Picture credit: Google

What is the purpose of climate fiction?

Cli-fi or Climate fiction has gained traction over the past few years. It turns the spotlight on issues relating to climate change and the fall-out of human activity on the environment and the future of our planet.

Commenting on Jim Laughters Polar City Red, a novel set around climate refugees in a future Alaska, Dan Bloom, a freelance writer coined the term cli-fi. In his description of the genre, Bloom calls it a route to wake people up through storytelling.

Climate fiction or Climate change fiction, popularly abbreviated as Cli-Fi modelled after the assonance of Sci-fi (Science fiction), is literature that deals with global warming and climate change. Not necessarily speculative in nature, the works of cli-fi may take place in the world as we know it or in the future.

Where to get started with climate fiction?

Although the term Cli-fi came into use in the late 2000s to describe novels and movies that deal with man-made climate change, historically there have been any number of literary works that have thematically dealt with climate change as a natural disaster. Some important books from this genre are:

Parable of the Sower by American writer Octavia E. Butler

It is probably the quintessential Cli-fi book. Published in 1993, it narrates the story of Lauren Olamina, a young girl growing up in California in the years 2024-2027. Our protagonist suffers from a debilitating disability called hyper-empathy which makes her extremely sensitive to the emotions of other people.

Set in a time when climate change and disease outbreaks have increased social disorder, this novel follows Lauren in her quest for freedom. Several characters from various walks of life join her on her journey north and learn of a religion she has crafted titled Earthseed. This religion emphasises the idea that one’s final mission in life is to inhabit other planets.

Parable of the Sower has won multiple awards, including the 1994 New York Times Notable Book of the Year, and has been adapted into a concert and a graphic novel.

The MaddAddam Trilogy by Margaret Atwood

Set in a darkly plausible future shaped by plagues, floods, and genetic engineering these books talk about the price of development. This trilogy comprises Ong and Crake (2003). The Year of the Hood (2009). and MaddAddam (2013)

Oryx and Crake begins with Jimmy or snowman waking to a desolate world. A reality where humankind has been nearly destroyed by a 21st Century plague spread through a health supplement called BlyssPluss pill The Year of the flood tells the other side of the story and gives us the view from the wildemess where God’s gardeners struggle to lead non-violent lives in a degraded landscape. MaddAddam the final book in the series brings together survivors from both the previous books looking towards the possibility of regeneration.

Gun Island by Amitav Ghosh The book Deen, a New York-based antiquarian book dealer who goes into the Sundarbans, the (disappearing) wetlands wedged between India and Bangladesh, in search of a shrine and the truth behind the myth of the Gun Merchant and Manasi Devi, the goddess of snakes.

Picture Credit : Google 

What is the largest carnivorous marsupial?

The Tasmanian devil is the largest carnivorous marsupial, known for their high-pitched squeal and aggressive temperament. They have held this title for over 80 years. Specifically, these creatures weigh between 9 and 29 pounds. A Tasmanian Devil weighing 29 pounds is as heavy as three one-gallon cans of paint. These mammals range from 20 to 31 inches long. Picture two bowling pins lined up end to end and you have the length of a 31-inch Tasmanian Devil. This mammal’s tail is equal to half of its body length. These animals store fat in their tail to use for energy. So, if you see one of these animals with a thick tail, you know it’s healthy. Thanks to conservation efforts, they are being reintroduced to Australian mainland after a 3,000-year gap. Mother devils can give birth to 50 young ones at one go. However, very few survive.

A Tasmanian Devil is a small animal with short brown or black fur with a stripe of white hair across its chest. Some of these marsupials have patches of white hair near their dark tail. This marsupial’s front legs are longer than its back ones. They have dark eyes and small mouselike ears. These animals have excellent sight and hearing allowing them to track down prey at night.

They are known for their very strong jaws. In fact, this marsupial’s jaws have a bite force of 94 pounds. That strong bite force allows them to easily consume the meat, hair, bones, and organs of the dead animals they find. Some scientists refer to Tasmanian Devils as environmental vacuums because they clean up the carcasses they find in their habitat.

Credit : A-Z-Animals

Picture Credit : Google