Which is the smallest planet in the solar system?

Mercury is the smallest planet in our solar system. Located closest to the Sun, it is also the fastest planet in our solar system, travelling at a speed of nearly 47 kilometres per second. In fact, the closer a planet is to the Sun, the faster it travels. Mercury completes one circle around the Sun in just about 88 Earth-days.

When observed from its surface, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight is as much as seven times brighter. But despite this proximity to the Sun, Mercury is not the hottest planet in our solar system- it is Venus. The reason for this is Venus' dense atmosphere.

Another interesting aspect of Mercury is that the Sun appears to rise briefly, set, and rise again from some parts of the planet's surface due to its elliptical and egg-shaped orbit, and sluggish rotation. The same phenomenon happens in reverse during sunset.

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Where is world's Largest Solar Tree?

The largest solar tree in the world has been installed at the CSIR-CMERI Centre of Excellence for Farm Machinery in Ludhiana, Punjab.

A solar power tree is a device that is shaped like a tree with its steel branches holding the solar photovoltaic panels.

Just like a natural tree, the steel branches of the solar tree are arranged in such a fashion that every solar panel is properly exposed to the Sun. Moreover, the panels can be mechanically tilted east or west to derive maximum benefit of the Sun's position. The height of the tree is about 9-10 metres. One tree can produce about 5kW of power.

One of the main hurdles in installing solar power plants is the lack of availability of large spaces. Often, farmers are reluctant to sacrifice their cultivable land for solar power production. But a solar tree with its vertically arranged branches, occupies only four sqft of area, leaving almost the entire land free for cultivation. The energy generated can be used to run pumps, e-tractors and tillers as a green alternative to diesel.

India's first solar power tree was produced by Central Mechanical Engineering and Research Institute (CMERI), at Durgapur. The largest solar tree in the world has been installed at the CSIR-CMERI Centre of Excellence for Farm Machinery in Ludhiana. Its total solar PV panel surface area is 309.83 m2. CMERI hopes to install many such solar trees along highways and farmlands.

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WHICH IS THE FIRST FULLY SOLAR-POWERED EDUCATIONAL INSTITUTE IN INDIA?

The Sri Aurobindo International Centre for Education in Puducherry is the first fully solar-powered educational institute in India. With solar panels installed on almost all the rooftops in the campus, the school produces three times more energy than what it consumes.  

Many schools encourage their students to switch off the fans and lights after use, plant trees and take other initiatives to save energy. However, very few go beyond just asking them to take precautions and save energy. SAICE is different. This educational institute is self-reliant in terms of energy; it meets all its energy requirements through solar power. Moreover, it produces three times the electricity it consumes and lights up many other buildings with the excess energy. And it has done so by devising and implementing a project almost entirely on its own.

SAICE is a part of the Sri Aurobindo Ashram in Pondicherry. It was in 2012 that Dr. Brahmanand Mohanty, an alumnus of SAICE, came up with the idea of making the ashram energy efficient with the help of a sustainable model.

Dr. Mohanty had a vision of developing a system that would make SAICE self-dependent for energy. With this in mind, he had a meeting with the trustees of the Ashram. They gave him the go ahead and even suggested that pilot research activities should be taken up with the active participation of the young teachers and students at the Institute. And then it all began. The whole project was conducted in two phases from 2012 to 2015.

Following this analysis, all inefficient lamps, fans, air conditioners, and computers, which had been in use since a long period of time, were substituted by more energy-efficient alternatives to lower the energy demand by more than 25 percent, without compromising on the quality and service.

With a better understanding of how much energy the educational institute was consuming, they came to the decision that a solar power plant should be installed inside the campus so as to meet all the energy demands in-house. Thus, a 17 kWp rooftop solar power plant was set up in the school by an Auroville-based solar installer.Teachers and students were involved in the entire process right from the start. They helped in the basic wiring, setting up the panels on the rooftop, and more.

Credit : The better india

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WHICH IS THE FIRST CARBON NEUTRAL VILLAGE IN INDIA?

Palli, a village in Jammu and Kashmir's border district of Samba, became India's first "carbon-neutral panchayat on April 24, 2022, with Prime Minister Narendra Modi dedicating to the nation a 500-kilowatt solar plant. Palli, according to the Prime Minister, has shown the way to the country by becoming carbon neutral. But what is carbon neutrality and how can it be achieved? Let's find out.

What is carbon neutrality?

We all know that carbon dioxide emissions are one of the primary causes of climate change and an increasingly warming planet. Carbon-neutrality is the state of achieving a balance between the greenhouse gases put out into the atmosphere and those removed. The term 'Net-zero' is sometimes used instead of carbon neutrality and they broadly mean the same. Increasingly, countries, companies, and organisations have been committing to achieve carbon-neutrality or net-zero carbon emission through measures such as reforestation and artificial carbon sequestering. But some environmental activists have criticised such offsetting measures as an excuse to continue polluting. If you've been wondering about the benefits of achieving carbon neutrality, there are many such as less pollution, improved air quality, better health and environment, green jobs, reducing the impact of climate change, and a greener planet.

How can it be achieved?

Carbon neutrality can be achieved by reducing the use of fossil fuels and by adopting renewable energy sources, by developing energy-efficient technologies, by adopting massive reforestation or tree-planting measures and by investing in technologies such as carbon sequestration that can remove carbon from the atmosphere. By the way, carbon sequestration is the process of capturing and storing atmospheric carbon dioxide underground permanently and safely. However, no technology or quantity of trees planted could offset the emissions currently generated globally, unless every country and every household is part of this solution.

Palli's feat

The unassuming village of Palli has made history by becoming India's first carbon-neutral solar village. It has achieved this feat with the installation of a 500-kilowatt solar plant. According to reports, the project was finished in record time (of nearly three weeks) at a cost of Rs. 2.75 crore. Under the central government's 'Gram Urja Swaraj' programme, as many as 1,500 solar panels put up on an area of 6,408 square metres will provide clean electricity to 340 homes in the model panchayat.

The green energy generated will be distributed to the village through the local power grid station, which has a daily requirement of 2,000 units.

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WHICH IS THE LARGEST SOLAR PARK IN THE WORLD?

Bhadla Solar Park is the largest solar park in India and in the world. Located in Bhadla, north of Jodhpur, it spans 14,000 acres, with over 10 million solar panels contributing to an operational capacity of 2245MW. The panels are cleaned by robots and monitored by humans. Bhadla is a sandy, arid region described as "almost unlivable" with normal temperatures of 46-48°C, and frequent hot winds and sandstorms. The region receives a good amount of radiation ideal for the generation of solar energy.

The entire project was divided into four phases. In the first phase of the park's establishment, solar panels were established to produce 65 MW of energy in capacities ranging from 5 MW to 25 MW. The following step of the project comprised of commissioning of the second phase of 680 MW. The first two phases of the park were developed by the Rajasthan Solar Power Park Company Limited. Saurya Urja Company of Rajasthan developed the third instalment. The project's final stage was designed by Adani renewable energy park for the capacity of 500 MW.

The auction conducted for Bhadla Solar Park recorded the price per unit fall to as low as ?2.62. Surprisingly, the price is lower than National Thermal Power Corporation (NTPC) Limited's price of ?3.20 per unit. The Indian Express quoted a senior official, "Bhadla Ph-IV Solar Park results in a historic lowering of tariffs. Phelan Energy (50MW) and Avaada Power (100 MW) have bagged projects at Rs 2.62/unit. Softbank Cleantech has won 100 MW capacity at Rs 2.63/unit".
India's has strongly started working in the direction of producing solar energy in recent years. Currently, there are over 30 massive solar projects at various stages in the country. With investments in solar projects, India is consistently working towards reducing its dependence on imported fossil fuels. Moreover, in rural areas, solar-powered lighting is proving much more beneficial than indoor lighting by kerosene. In June 2021, PM Narendra Modi said that India had increased its renewable energy capacity by 250 per cent since 2014. India has one of the fastest-growing populations and economies, which would directly benefit from increased renewable energy resources.

Credit : The logical indian

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Which is the world's largest permanent scale model of the Solar System?

The Sweden Solar System is the world's largest permanent scale model of the Solar System. It is in the scale of 1:20 million and stretches 950 km across the country. The bodies represented include the Sun, the planets (and some of their moons), dwarf planets and other small bodies (comets, asteroids, trans-Neptunians, etc.). The Sun is represented by the Avicii Arena in Stockholm, the largest hemispherical building in the world. The planets, all appropriately scaled, are all around Stockholm and its suburbs.

So far, all eight official planets and dwarf-planet Pluto are in place, at distances from 2.9 km (Mercury) to 300 km (Pluto) from the Globe Northwards. Not limiting themselves to metallic spheres, Jupiter is presently a flower arrangement on a roundabout island outside Arlanda airport; Neptune is an acrylic sphere that shines with the planet’s iconic blue light at night. Comets like Halley and Swift-Tuttle have also been introduced to the system, though South-West of the Globe; foundations have been built for a representation of Termination Shock, the edge of the heliosphere, at the Institute of Space Physics in Kiruna, some 950 km North of the Globe, above the Arctic Circle.

Of course, most tourists do not have the time to fling up and down the coast of the Baltic Sea looking for a lot of small, round things, so it is fortunate that most of this Solar System can be found close to Stockholm.

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Which is the hottest planet?

The farther you get away from the Sun, the cooler you get. So let’s take a look at those planets that sit between Earth and the Sun: Mercury and Venus.

Since Mercury sits closest to the Sun, it must be the hottest planet. Right? That only makes sense, doesn’t it? After all, Mercury receives more sunlight per square foot than any other planet in the solar system. Wrong! Venus is actually the hottest planet in the solar system.

On a hot day on Mercury, the temperature can rise to over 700 ºF. That’s hot! You’d definitely need plenty of sunscreen there. A hot day on Venus, however, is even hotter. How much so? The highest temperatures on Venus exceed 900 ºF. Yikes! Now that’s a scorcher, for sure.

Most friends are probably wondering why Venus is hotter than Mercury. After all, it’s farther away from the Sun. The answer lies in the atmosphere. 

Mercury is small and sits closest to the Sun. It also moves very quickly around the Sun. For these reasons, it doesn’t have an atmosphere. When the Sun’s rays hit Mercury, they just bounce off into space. There’s nothing to reflect them back toward the planet and retain their heat.

Venus, on the other hand, has a very thick atmosphere. Its atmosphere is actually over 90 times denser than Earth’s atmosphere. It’s also made up mostly of carbon dioxide, a greenhouse gas. Venus’s atmosphere acts like a one-way door. It lets in solar radiation, but it doesn’t let it back out.

This creates oven-like conditions on the surface of Venus. Because of this intense heat, no water can be found there. Moreover, carbon dioxide is a noxious gas. It creates raging winds that blow constantly across the surface of the planet. This gives it one of the harshest environments you’re likely to find in the entire solar system. Earth and Venus are sometimes called “sister” planets because of their similar sizes. But in most other ways, they couldn’t be more different.

Before scientists could see Venus with the help of unmanned probes and space telescopes, many of them thought Venus was a lush, tropical paradise. The truth is that it’s a barren rock that looks like Earth’s Moon. Its clouds appear yellowish because of the presence of sulfur dioxide alongside the huge amounts of carbon dioxide.

Credit : Wonderopolis 

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Which is the only planet where day longer than year?

Just to be clear, this answer to ‘which planet has the longest day’ is based on this criteria: a planets day is how long it takes it to complete one rotation on its axis. This is also referred to as its rotational period. So, Venus has the longest day of any planet in our solar system. It completes one rotation every 243 Earth days. Its day lasts longer than its orbit. It orbits the Sun every 224.65 Earth days, so a day is nearly 20 Earth days longer than its year.

Now, back to why the Venusian day is longer than its year. Venus is closer to the Sun; therefore, its orbit takes a shorter period of time than its rotation upon its axis. The planet also rotates in retrograde. That means it spins in the opposite direction of the Earth. If you were standing on Venus, you could see the Sun rise in the West and set in the East.

A manned Venus flyby mission was proposed in the late 1960s. The mission was planned to launch in late October or early November 1973, and would have used a Saturn V rocket to send three men. The flight would have lasted approximately one year. The spacecraft would have passed approximately 5,000 km from the surface about four months into the flight. There have been several unmanned probes and flybys of the planet, including MESSENGER and the Venus Express. Future proposed missions include the BepiColombo, Venus InSitu Explorer, and the Venera-D.

Credit : Universe Today 

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What is it called when the Earth orbits the Sun?

Imagine a line passing through the center of Earth that goes through both the North Pole and the South Pole. This imaginary line is called an axis. Earth spins around its axis, just as a top spins around its spindle. This spinning movement is called Earth’s rotation. At the same time that the Earth spins on its axis, it also orbits, or revolves around the Sun. This movement is called revolution. A pendulum set in motion will not change its motion, and so the direction of its swinging should not change. However, Foucault observed that his pendulum did seem to change direction. Since he knew that the pendulum could not change its motion, he concluded that the Earth, underneath the pendulum was moving. An observer in space will see that Earth requires 23 hours, 56 minutes, and 4 seconds to make one complete rotation on its axis. But because Earth moves around the Sun at the same time that it is rotating, the planet must turn just a little bit more to reach the same place relative to the Sun. Hence the length of a day on Earth is actually 24 hours. At the equator, the Earth rotates at a speed of about 1,700 km per hour, but at the poles the movement speed is nearly nothing.

For Earth to make one complete revolution around the Sun takes 365.24 days. This amount of time is the definition of one year. The gravitational pull of the Sun keeps Earth and the other planets in orbit around the star. Like the other planets, Earth’s orbital path is an ellipse so the planet is sometimes farther away from the Sun than at other times. The closest Earth gets to the Sun each year is at perihelion (147 million km) on about January 3rd and the furthest is at aphelion (152 million km) on July 4th. Earth’s elliptical orbit has nothing to do with Earth’s seasons. During one revolution around the Sun, Earth travels at an average distance of about 150 million km. Earth revolves around the Sun at an average speed of about 27 km (17 mi) per second, but the speed is not constant. The planet moves slower when it is at aphelion and faster when it is at perihelion. The reason the Earth (or any planet) has seasons is that Earth is tilted 23 1/2oon its axis. During the Northern Hemisphere summer the North Pole points toward the Sun, and in the Northern Hemisphere winter the North Pole is tilted away from the Sun.

Credit : Lumen Learning 

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Which planets have no moons?

Of the terrestrial (rocky) planets of the inner solar system, neither Mercury nor Venus have any moons at all, Earth has one and Mars has its two small moons. In the outer solar system, the gas giants Jupiter and Saturn and the ice giants Uranus and Neptune have dozens of moons. 

Jupiter's menagerie of moons includes the largest in the solar system (Ganymede), an ocean moon (Europa) and a volcanic moon (Io). Many of Jupiter's outer moons have highly elliptical orbits and orbit backwards (opposite to the spin of the planet). Saturn, Uranus and Neptune also have some irregular moons, which orbit far from their respective planets.

Saturn has two ocean moons – Enceladus and Titan. Both have subsurface oceans and Titan also has surface seas of lakes of ethane and methane. The chunks of ice and rock in Saturn's rings (and the particles in the rings of the other outer planets) are not considered moons, yet embedded in Saturn's rings are distinct moons or moonlets. These shepherd moons help keep the rings in line. Titan, the second largest in the solar system, is the only moon with a thick atmosphere.

In the realm of the ice giants, Uranus's inner moons appear to be about half water ice and half rock. Miranda is the most unusual; its chopped-up appearance shows the scars of impacts of large rocky bodies.

Neptune's moon Triton is as big as Pluto and orbits backwards compared with Neptune's direction of rotation.

Credit : NASA Science

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What does the earth have that the moon does not?

The earth has about 70 percent of water on its crust. It also has an abundance of oxygen thanks to its multilayered atmosphere made of several gasses. The moon neither has oxygen nor water. It weak atmosphere does not support the formation of oxygen. Hence it remains a barren and lifeless astral body. However, the possibilities of finding water and ice on the moon are being explored by humans through several studies now.

The moon has only a very thin atmosphere, so a layer of dust — or a footprint — can sit undisturbed for centuries. And without much of an atmosphere, heat is not held near the surface, so temperatures vary wildly. Daytime temperatures on the sunny side of the moon reach 273 degrees F (134 Celsius); on the night side it gets as cold as minus 243 F (minus 153 C).

The moon's gravity pulls at the Earth, causing predictable rises and falls in sea levels known as tides. To a much smaller extent, tides also occur in lakes, the atmosphere and within Earth's crust.

High tides refer to water bulging up from Earth's surface, and low tides when water levels drop. High tides occur on the side of the Earth nearest the moon due to gravity, and on the side farthest from the moon due to the inertia of water. Low tides occur between these two humps.

The pull of the moon is also slowing the Earth's rotation, an effect known as tidal braking, which increases the length of our day by 2.3 milliseconds per century. The energy that Earth loses is picked up by the moon, increasing its distance from the Earth, which means the moon gets farther away by 1.5 inches (3.8 centimeters) annually.

Credit : Space.com 

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How many moons does Saturn have?

Saturn has 82 moons. Fifty-three moons are confirmed and named and another 29 moons are awaiting confirmation of discovery and official naming. Saturn's moons range in size from larger than the planet Mercury — the giant moon Titan — to as small as a sports arena. The moons shape, contribute and also collect material from Saturn's rings and magnetosphere.

Including provisional moons, Saturn has 82 total possible moons, while Jupiter has 79. Gas giants like these planets are so large and have such strong gravitational fields, they're able to attract far more satellites than a planet, like say, Earth, with its one moon. And these numbers of moons will likely change in the future as astronomers continue observing Saturn and Jupiter and the many bodies that orbit them both. Jupiter may even overtake Saturn at some point in the future.

While Jupiter is known for its four large Galilean moons (so named because they were observed by Galileo with his 17th century telescope), Saturn has two moons that have drawn astronomers' attention: Enceladus and Titan.

Both Enceladus and Titan are ocean moons, meaning they have subsurface oceans of liquid water. Titan even has surface lakes, though these are composed of methane and ethane. Enceladus is an icy moon known for spraying huge plumes of water up through its atmosphere into space; during the Cassini mission, astronomers were able to sample these geysers and that's how they discovered the ocean underneath its icy crust.

Credit : How stuff works

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What do scientists think caused the formation of the moon?

'There used to be a number of theories about how the Moon was made and it was one of the aims of the Apollo program to figure out how we got to have our Moon,' says Sara.

Prior to the Apollo mission research there were three theories about how the Moon formed.

Capture theory suggests that the Moon was a wandering body (like an asteroid) that formed elsewhere in the solar system and was captured by Earth's gravity as it passed nearby. In contrast, accretion theory suggested that the Moon was created along with Earth at its formation. Finally, according to the fission scenario, Earth had been spinning so fast that some material broke away and began to orbit the planet.

What is most widely accepted today is the giant-impact theory. It proposes that the Moon formed during a collision between the Earth and another small planet, about the size of Mars. The debris from this impact collected in an orbit around Earth to form the Moon.

Credit : Natural History Museum

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How many earths could fit inside the sun?

The sun is large enough that approximately 1.3 million Earths could fit inside. Want to check our math? The volume of the sun is 1.41 x 1018 km3, while the volume of Earth is 1.08 x 1012 km3. If you divide the volume of the sun by the volume of the Earth, you get that roughly 1.3 million Earths can fit inside the sun. However, this assumes that the Earths are squished together without leaving any empty space. Scientists estimate that if the Earths retained their spherical shape, only about 960,000 would fit because of wasted space in between the spheres.

Of course, the Sun is a fairly average sized stars. There are some enormous stars out there. For example, the red giant Betelgeuse has a radius of 936 times the radius of the Sun. That gives it hundreds of millions of times more volume than the Sun.

And the largest known star is VY Canis Majoris, thought to be between 1800 and 2100 times the radius of the Sun.

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What is the sun?

The sun is a star, a hot ball of glowing gases at the heart of our solar system. Its influence extends far beyond the orbits of distant Neptune and Pluto. Without the sun's intense energy and heat, there would be no life on Earth. And though it is special to us, there are billions of stars like our sun scattered across the Milky Way galaxy. If the sun were as tall as a typical front door, the Earth would be the size of a U.S. nickel. The temperature at the sun's core is about 27 million degrees Fahrenheit.

The sun lies at the heart of the solar system, where it is by far the largest object. It holds 99.8% of the solar system's mass and is roughly 109 times the diameter of the Earth — about one million Earths could fit inside the sun. 

The surface of the sun is about 10,000 degrees Fahrenheit (5,500 degrees Celsius) hot, while temperatures in the core reach more than 27 million F (15 million C), driven by nuclear reactions. One would need to explode 100 billion tons of dynamite every second to match the energy produced by the sun, according to NASA.

The sun is one of more than 100 billion stars in the Milky Way. It orbits some 25,000 light-years from the galactic core, completing a revolution once every 250 million years or so. The sun is relatively young, part of a generation of stars known as Population I, which are relatively rich in elements heavier than helium. An older generation of stars is called Population II, and an earlier generation of Population III may have existed, although no members of this generation are known yet.

The sun was born about 4.6 billion years ago. Many scientists think the sun and the rest of the solar system formed from a giant, rotating cloud of gas and dust known as the solar nebula. As the nebula collapsed because of its gravity, it spun faster and flattened into a disk. Most of the material was pulled toward the center to form the sun.

The sun has enough nuclear fuel to stay much as it is now for another 5 billion years. After that, it will swell to become a red giant. Eventually, it will shed its outer layers, and the remaining core will collapse to become a white dwarf. Slowly, the white dwarf will fade, and will enter its final phase as a dim, cool theoretical object sometimes known as a black dwarf.

Credit : Space.com

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