Which is the largest planet?

The largest planet in our solar system, Jupiter, is located fifth from the Sun. It is more than two times the size of all the planets in our solar system combined. Jupiter has also been instrumental in our understanding of the universe and our place in it. In 1610, Galileo discovered Jupiter's four large moons: lo, Europa, Ganymede and Callisto. This confirmed the Copernican view that the Earth was not the centre of the universe as these newly discovered celestial objects were revolving around another planet.

It is estimated that eleven Earths could fit across Jupiter's equator. To put it in other words, if our planet is the size of a grape, then Jupiter is the size of a basket-ball. It has an iconic Great Red Spot, which is a giant storm that has been active in Jupiter's atmosphere for hundreds of years. This storm is bigger than the Earth!

Jupiter's orbit is about 778 million kilometres or 5.2 Astronomical Units (AU) from the Sun (Earth is one AU from the Sun). Jupiter is a gas giant, which lacks an Earth-like atmosphere. Even if it has a solid inner core at all, it would only be about the size of the Earth. Jupiter's atmosphere contains mainly hydrogen (H) and helium (He) and has more than 75 moons. It rotates about its axis once every 10 hours (a Jovian day), and takes about 12 Earth years to complete one revolution about its orbit around the Sun (a Jovian year).

In the year 1979, NASA's Voyager mission discovered Jupiter's faint ring system. We have discovered that all the four giant planets of our solar system have ring systems. Till date, nine spacecraft have visited Jupiter. Of them, only the most recent one landed on Jupiter. Seven of them only flew by this gas giant and the other two just orbited it. Juno, the latest spacecraft, arrived on Jupiter in 2016.

Although it is the biggest planet in our solar system, Jupiter cannot support life as we know it. But we have come to know that some of its moons have oceans beneath their crusts, which could possibly support some form of life.

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WHAT ARE THE FOUR FUNDAMENTAL FORCES OF NATURE?

The Four Fundamental Forces of Nature are Gravitational force, Weak Nuclear force, Electromagnetic force and Strong Nuclear force. The Four Fundamental Forces of Nature are Gravitational force, Weak Nuclear force, Electromagnetic force and Strong Nuclear force.

Gravitational Force

The gravitational force is weak but very long-ranged. Furthermore, it is always attractive. It acts between any two pieces of matter in the Universe since mass is its source.

Weak Nuclear Force

The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and. As its name indicates, it is very weak. The weak force causes Beta-decay ie. the conversion of a neutron into a proton, an electron and an antineutrino.

Electromagnetic Force

The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It is long-ranged but much weaker than the strong force. It can be attractive or repulsive and acts only between pieces of matter carrying an electrical charge. Electricity, magnetism, and light are all produced by this force.

Strong Nuclear Force

The strong interaction is very strong but very short-ranged. It is responsible for holding the nuclei of atoms together. It is basically attractive but can be effectively repulsive in some circumstances. The strong force is ‘carried’ by particles called gluons; that is, when two particles interact through the strong force, they do so by exchanging gluons. Thus, the quarks inside of the protons and neutrons are bound together by the exchange of the strong nuclear force.

Note:  While they are close together the quarks experience little force, but as they separate the force between them grows rapidly, pulling them back together. To separate two quarks completely would require far more energy than any possible particle accelerator could provide.

Credit : Clearias

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WHY DO THE CONTINENTS MOVE?

The surface of Earth is broken into giant fragments called tectonic plates. The continents are situated on top of these tectonic plates, which carry them much like cargo on rafts. The plates move at rates of between 2 and 17 cm per year, and over millions of years this moves the continents over many thousands of kilometres.

The earth’s crust is broken into separate pieces called tectonic plates. The crust is the solid, rocky, outer shell of the planet. It is composed of two distinctly different types of material: the less-dense continental crust and the more-dense oceanic crust. Both types of crust rest atop solid, upper mantle material. The upper mantle, in turn, floats on a denser layer of lower mantle that is much like thick molten tar.

Each tectonic plate is free-floating and can move independently. Earthquakes and volcanoes are the direct result of the movement of tectonic plates at fault lines. The term fault is used to describe the boundary between tectonic plates. Most of the earthquakes and volcanoes around the Pacific ocean basin—a pattern known as the “ring of fire”—are due to the movement of tectonic plates in this region. Other observable results of short-term plate movement include the gradual widening of the Great Rift lakes in eastern Africa and the rising of the Himalayan Mountain range. The motion of plates can be described in four general patterns:

  • Collision: when two continental plates are shoved together
  • Subduction: when one plate plunges beneath another
  • Spreading: when two plates are pushed apart
  • Transform faulting: when two plates slide past each other

Credit: EXPLORING OUR FLUID EARTH

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WHAT IS SIGNIFICANT ABOUT THE CENOZOIC ERA?

Life on our planet developed millions of years ago, but if large life-forms are taken into consideration, then intelligent organisms like the Homo sapiens have never dominated any specific era or even a period. The Cenozoic Era can be known as the arrival and dominance of intelligent life-forms like modern human beings, which changed the world scenario permanently.

The term 'Cenozoic' has been derived from the Greek words: kainos meaning 'new' and zoe meaning 'life'. It is the shortest era of the Earth, spanning from about 66 million years ago to the present. After the sudden K-T boundary mass extinction, mammals got a chance to evolve extensively in this era, and hence, it is also called 'The Age of The Mammals'. The climate of our planet stabilized and atmospheric oxygen slowly increases with a simultaneous decrease in carbon dioxide and other toxic gaseous elements.

Earlier, the Cenozoic comprised two periods: Tertiary and Quaternary, the former being divided into Paleogene and Neogene, but now the term Tertiary is slowly phased out. Instead, the era is now divided into three periods: Paleogene, Neogene, and Quaternary, ranging from the oldest to the youngest. They are again subdivided into a number of stages/epochs. Apart from mammals, the Aves class of Chordates, i.e., the birds also evolved a lot, and several of them were larger than the average height of a human.

Credit: science.earthjay.com

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WHY DOES EARTH LOOK BLUE FROM SPACE?

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

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DOES THE EARTH SPIN AT A TILT?

Yes, Earth spins around a line between the poles called its axis. The axis is tilted over at 23.5° in relation to the Sun. Earth rotates once every 23 hours, 56 minutes and 4.09 seconds. The Sun thus appears to come back to the same place in the sky once every 24 hours.

Earth’s spin, tilt, and orbit affect the amount of solar energy received by any particular region of the globe, depending on latitude, time of day, and time of year. Small changes in the angle of Earth’s tilt and the shape of its orbit around the Sun cause changes in climate over a span of 10,000 to 100,000 years, and are not causing climate change today.

Daily changes in light and temperature are caused by the rotation of the Earth, and seasonal changes are caused by the tilt of the Earth. As the Earth orbits the Sun, the Earth is pulled by the gravitational forces of the Sun, Moon, and large planets in the solar system, primarily Jupiter and Saturn. Over long periods of time, the gravitational pull of other members of our solar system slowly change Earth’s spin, tilt, and orbit. Over approximately 100,000 – 400,000 years, gravitational forces slowly change Earth’s orbit between more circular and elliptical shapes. Over 19,000 – 24,000 years, the direction of Earth’s tilt shifts (spins). Additionally, how much Earth’s axis is tilted towards or away from the Sun changes through time, over approximately 41,000 year cycles. Small changes in Earth’s spin, tilt, and orbit over these long periods of time can change the amount of sunlight received (and therefore absorbed and re-radiated) by different parts of the Earth. Over 10s to 100s of thousands of years, these small changes in the position of the Earth in relationship to the Sun can change the amount of solar radiation, also known as insolation, received by different parts of the Earth. In turn, changes in insolation over these long periods of time can change regional climates and the length and intensity of the seasons. The Earth’s spin, tilt, and orbit continue to change today, but do not explain the current rapid climate change.

credit: UNDERSTANDING GLOBAL CHANGE

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What are the fun facts of great Indian bustard?

It is great Indian bustard, a bird native to the Indian Subcontinent. It prefers open grasslands.

It has a large body and long legs. The black crown on the forehead is among its unique features. It is among the heaviest flying birds.

Its diet includes a wide range of things - grass, seeds, insects such as grasshoppers and beetles, and sometimes small rodents and reptiles.

With less than 200 individuals left in the wild, it is considered critically endangered.

Great Indian bustards are tall birds with long legs and a long neck; the tallest individuals may stand up to 1.2 metres (4 feet) tall. The sexes are roughly the same size, with the largest individuals weighing 15 kg (33 pounds). Males and females are distinguished by the colour of their feathers. Feathers on the top of the head are black in males, which also possess a whitish neck, breast, and underparts, along with brown wings highlighted by black and gray markings. Males also have a small, narrow band of black feathers across the breast. In contrast, females possess a smaller black crown on the top of the head, and the black breast band is either discontinuous or absent.

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What are the fun facts of Malabar pit viper?

Malabar pit viper is a venomous snake species endemic to southwestern India. It inhabits moist- evergreen and deciduous forests.

It comes in all colours - yellow, green and brown – and patterns. The tail is prehensile, adapted for grasping or holding (say, trees). It is nocturnal, sometimes seen basking on rocks or trees near streams. It is specifically active during the monsoon season.

It preys on tree frogs, geckos and small animals. It is slow-moving, but capable of fast strikes.

Pit Viper is a slow-moving snake and nocturnal. They rely on camouflage for protection. Although slow to defend themselves, they are capable of fast strikes and bites if disturbed. The food of this snake consist of small mammals like rodents, lizards, birds and frogs. The females give birth to 4 or 5 living young. This is also Viper speciality as other snakes lay eggs. The eggs develop inside the mother’s body surrounded by transparent bags, called membranes. While the baby snake is developing inside the mother, it gets its food from the yolk of the egg. The female viper usually gives birth in a hidden place, where the young are safe from enemies.

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What is waterspout?

Despite its name, a waterspout is not filled with water from the ocean or lake. A waterspout descends from a cumulus cloud. It does not "spout" from the water. The water inside a waterspout is formed by condensation in the cloud. 

There are two major types of waterspouts: tornadic waterspouts and fair-weather waterspouts.

Tornadic waterspouts get their start as true tornadoes. Influenced by winds associated with severe thunderstorms, air rises and rotates on a vertical axis. Tornadic waterspouts are the most powerful and destructive type of waterspout. 

Fair-weather waterspouts, however, are much more common. Fair-weather waterspouts are rarely dangerous. The clouds from which they descend are not fast-moving, so fair-weather waterspouts are often static. Fair-weather waterspouts are associated with developing storm systems, but not storms themselves.

Both tornadic and fair-weather waterspouts require high levels of humidity and a relatively warm water temperature compared to the overlying air. Waterspouts are most common in tropical and subtropical waters, such as the Florida Keys, the islands of Greece, and off the east coast of Australia.

Credit : National Geographic Society 

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What is avalanche?

During an avalanche, a mass of snow, rock, ice, soil, and other material slides swiftly down a mountainside. Avalanches of rocks or soil are often called landslides. Snowslides, the most common kind of avalanche, can sweep downhill faster than the fastest skier.

A snow avalanche begins when an unstable mass of snow breaks away from a slope. The snow picks up speed as it moves downhill, producing a river of snow and a cloud of icy particles that rises high into the air. The moving mass picks up even more snow as it rushes downhill. A large, fully developed avalanche can weigh as much as a million tons. It can travel faster than 320 kilometers per hour (200 miles per hour).

Avalanches occur as layers in a snowpack slide off. A snowpack is simply layers of snow that build up in an area, such as the side of a mountain. In winter, repeated snowfalls build a snowpack dozens of meters thick. The layers vary in thickness and texture.

The bonds between the layers of a snowpack may be weak. Melted snow that refreezes may cause a slick coating of ice to form on the surface of a layer. A new snowfall may not stick to this slippery layer, and it may slide off. During spring thaw, melted snow can seep through a snowpack, making the surface of a lower layer slippery. Added weight or vibration can easily send the top layers of a snowpack hurtling downhill.

Credit : National Geographic Society 

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What is sandstorm?

Sand and dust storms are common meteorological hazards in arid and semi-arid regions. They are usually caused by thunderstorms – or strong pressure gradients associated with cyclones – which increase wind speed over a wide area. These strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere, transporting them hundreds to thousands of kilometres away. Some 40% of aerosols in the troposphere (the lowest layer of Earth’s atmosphere) are dust particles from wind erosion. The main sources of these mineral dusts are the arid regions of Northern Africa, the Arabian Peninsula, Central Asia and China. Comparatively, Australia, America and South Africa make minor, but still important, contributions. Global estimates of dust emissions, mainly derived from simulation models, vary between one and three Gigatons per year. 

Once released from the surface, dust particles are raised to higher levels of the troposphere by turbulent mixing and convective updrafts. They can then be transported by winds for lengths of time, depending on their size and meteorological conditions, before being pulled back down to the surface again. As larger particles sediment more quickly than smaller ones, there is a shift toward smaller particle sizes during transport. Dust is also washed out of the atmosphere by precipitation. The average lifetime of dust particles in the atmosphere ranges from a few hours for particles with a diameter larger than 10 ?m, to more than 10 days for the sub-micrometric ones.

Aerosols, particularly mineral dusts, impact weather as well as global and regional climate. Dust particles, especially if coated by pollution, act as condensation nuclei for warm cloud formation and as efficient ice nuclei agents for cold cloud generation. The ability of dust particles to serve as such depends on their size, shape and composition, which in turn depend on the nature of parent soils, emissions and transport processes. Modification of the microphysical composition of clouds changes their ability to absorb solar radiation, which indirectly affects the energy reaching the Earth’s surface. Dust particles also influence the growth of cloud droplets and ice crystals, thus affecting the amount and location of precipitation.

Airborne dust functions in a manner similar to the greenhouse effect: it absorbs and scatters solar radiation entering Earth’s atmosphere, reducing the amount reaching the surface, and absorbs long-wave radiation bouncing back up from the surface, re-emitting it in all directions. Again, the ability of dust particles to absorb solar radiation depends on their size, shape and mineralogical and chemical composition. The vertical distribution of dust in the air (vertical profile) and the characteristics of the underlying surface are also required to quantify this impact.

Credit : World Meteorological Organization  

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What is Tornado?

A tornado is a violently rotating column of air that extends from a thunderstorm to the ground. It's often portended by a dark, greenish sky. Black storm clouds gather. Baseball-size hail may fall. A funnel suddenly appears, as though descending from a cloud. The funnel hits the ground and roars forward with a sound like that of a freight train approaching. The tornado tears up everything in its path.

Every U.S. state has experienced twisters, but Texas holds the record: an annual average of 120. Tornadoes have been reported in Great Britain, India, Argentina, and other countries, but they are most often seen in the United States.

Related to tornadoes, waterspouts are weak twisters that form over warm water. They sometimes move inland and become tornadoes.

Dust devils are small, rapidly rotating columns of air that are made visible by the dust and dirt they pick up. Dust devils are not associated with thunderstorms. Either are fire tornadoes, which can spawn from wildfires.

The most violent tornadoes come from supercells, large thunderstorms that have winds already in rotation. About one in a thousand storms becomes a supercell, and one in five or six supercells spawns off a tornado.

Tornadoes can occur at any time of year, but they are more common during a distinct season that begins in early spring for the states along the Gulf of Mexico. The season follows the jet stream—as it swings farther north, so does tornado activity. May generally has more tornadoes than any other month, but April's twisters are sometimes more violent. Farther north, tornadoes tend to be more common later in summer.

Although they can occur at any time of the day or night, most tornadoes form in the late afternoon. By this time the sun has heated the ground and the atmosphere enough to produce thunderstorms.

Tornadoes form when warm, humid air collides with cold, dry air.

The denser cold air is pushed over the warm air, usually producing thunderstorms. The warm air rises through the colder air, causing an updraft. The updraft will begin to rotate if winds vary sharply in speed or direction.

As the rotating updraft, called a mesocycle, draws in more warm air from the moving thunderstorm, its rotation speed increases. Cool air fed by the jet stream, a strong band of wind in the atmosphere, provides even more energy.

Water droplets from the mesocyclone's moist air form a funnel cloud. The funnel continues to grow and eventually it descends from the cloud. When it touches the ground, it becomes a tornado.

Credit : National Geographic 

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What is Blizzard?

The term "blizzard" is often tossed around when big winter storms blow in. But the National Weather service has an official definition of blizzard:

A blizzard is a storm with "considerable falling or blowing snow" and winds in excess of 35 mph and visibilities of less than 1/4 mile for at least 3 hours.

While blizzard conditions may occur for shorter periods of time, the weather service is particular about its warning system:

When all the blizzard conditions are expected, the National Weather Service will issue a "blizzard warning." When just two of the above conditions are expected, a "winter storm warning" or "heavy snow warning" may be issued.

Blizzard conditions often develop on the northwest side of an intense storm system, meteorologists explain. The difference between the lower pressure in the storm and the higher pressure to the west creates a tight pressure gradient, or difference in pressure between two locations, which in turn results in very strong winds.

The strong winds blow falling snow and pick snow up from the ground, cutting visibility and creating big snow drifts.

Where did the term "blizzard" come from?

It had been used to describe a canon shot or a volley of musket fire. It first showed up to describe a snowstorm in an Iowa newspaper in the 1870s, according to the weather service.

Blizzards are most common in the upper Midwest and Great Plains, but they can occur anywhere strong snowstorms strike.

Credit : Live Science 

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What are unusual natural phenomena?

There are certain things in nature that do not occur regularly. While some of them continue to be mysteries, many have been understood scientifically. Let's take a glimpse of a few of them

A couple of years ago, a few beaches in Mumbai and in Chennai were shimmering in blue at night. It was due to the noctiluca algae that emits light known as bioluminescence.

As surreal and beautiful as it looks, this phenomenon could be linked to increasing global warming, according to marine researchers.

A murmuration is a phenomenon when hundreds or thousands of birds, usually starlings, fly in intricately coordinated patterns through the sky, for warding off a nearby predator.

Apparently, they never crash into each other. Scientists say this is because they usually interact among seven of their neighbours! And yes, this phenomenon has been sighted in India too.

Bright, dancing lights appear above the magnetic poles when electrically charged particles from the sun enter the Earth's atmosphere. The colours vary depending on the gas particles.

They are known as "aurora borealis" in the north and "aurora australis" in the south. Though it is not possible to predict aurora sightings with accuracy, usually, September to March is considered a good time for the northern lights and March to September for the southern lights.

This is the Blood Falls in Antarctica. It flows from the Taylor Glacier.

First spotted in 1911, the colour was a mystery. Finally a few years ago, it was discovered that the falls gets its colour from oxidised iron in saltwater.

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What is a keystone species?

A keystone species is one that has an incredibly important role to play in an ecosystem. Without this species, ecosystem would be dramatically different or may even stop existing altogether. It can be any organism, from large animals to microscopic bacteria. In short, a keystone species is what holds a habitat together.

There's a call to protect the tiger because as a keystone species, this top predator plays a significant role in the health and diversity of an ecosystem.

If it disappears, the population of its prey - usually ungulates - will go up, and this will result in the decimation of vegetation, leading to a collapse of the ecosystem.

Not just animals, birds and insects, even plants can be keystone species.

Mangroves are a keystone species that firm up shorelines and reduce erosion. They provide a safe haven and feeding area for small fish among their roots, which reach down through the shallow water.

It is true that if bees go extinct, so would humans. This keystone species plays a very important role in keeping the world going.

As the most important pollinators, they are responsible for about a third of the world's total food production. Without bees, there would be food shortage, and eventual human collapse.

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