Earth And The Solar System: Geography NCERT Notes for UPSC

Topic like The Solar System is important for UPSC aspirants i.e. sometimes questions are being asked in UPSC prelims exam apart from the mains examinations. This topic is important for other exams like state service exams, Railway, CDS and many more.

In this article we will cover important concepts like planets, stars, planet closest to the sun, third planet from the sun

the earth in the solar system, planets closest to earth,the sun planet,blue planet in solar system

planets around the sun,etc thus we will be able to improve not only our for UPSC Prelims but also we will be able to write and explain the concepts properly in our mains answer writing.By keeping all these things in mind, the Testbook prepares the best quality notes for UPSC aspirants.

Earth and the Solar System (UPSC Geography) NCERT Notes: Download PDF Here!

The Solar System

1. The solar system which is the assemblage generally consisting of the main star that is called the Sun.
2. It is a star that is averagely present in the Milky Way Galaxy and along with those bodies it is orbiting around it.
3. There are 8 or formerly 9 planets with about 210 known as planetary satellites moons. The moons are thought to be countless asteroids which are some with their own satellites and the comets and other icy bodies as well.
4. The vast reaches of gas which are highly tenuous and dust is known as the interplanetary medium.
5. These are located at the centre of the solar system and it usually influences the motion of all the other heavenly bodies as well.
6. Through it the force that is gravitational is the star sun. The star that is the sun which is in itself contains more than 99 percent of the system’s mass.
7. The planets which are in order of their distance outward from the Sun are the ones that are Mercury, Venus, and Earth, then Mars, next is Jupiter, then Saturn, and Uranus, and Neptune.
8. There are four planets that are Jupiter through Neptune which have the system of rings and all but except for Mercury and Venus which generally have one or more moons. The planet that is known as Pluto had been officially listed among the planets that is since it was discovered in 1930 orbiting beyond the planet that is Neptune. But we also saw that in 1992 there was an icy object that was discovered still farther from the Sun than planet Pluto.

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Planet Earth

The planet earth which is known as our home is the third planet from the sun. It’s the only planet which is said to have an atmosphere that contains free oxygen oceans of water on its surface and, of course, life as well.

It’s smaller than the four gas giants — that are Jupiter, then Saturn, next is Uranus and Neptune

But it is said to be larger than the three other rocky planets, that are Mercury, and Mars and then Venus.

We can also say that it’s not perfectly round. The water generally covers roughly 71 percent of Earth’s surface and most of that is in the oceans. About a fifth of the Earth consists of oxygen that is produced by plants. While scientists generally have been studying our planet for centuries much has been learned in recent decades too by studying pictures of planet Earth from space.

Read the NCERT Notes on Environment here.

Earth’s Internal Structure 

The core of the Earth is about 4,400 miles or 7,100 km wide, slightly larger than half the diameter of Earth’s and about the same size as the diameter of Mars’.

The outermost surface is about 1,400 miles or 2,250 km of the core that is liquid while the inner core is said to be a solid one.

It’s said to be about four-fifths as big as Earth’s moon which is at some 1,600 miles that is 2,600 km in diameter. The core is generally responsible for the planet’s magnetic field which generally helps to deflect the harmful charged particles that are shot from the sun.

Above the earth’s core there is a mantle which is about 1,800 miles or that is 2,900 km thick. The mantle is not stiff completely but can slowly flow. The crust of Earth’s floats on the mantle much like a wood piece that floats on water. The slow motion of the rock in the shuffle of the mantle that continents around and causes earthquakes, volcanoes and other things like the formation of mountain ranges.

Above the mantle the planet Earth has mainly two kinds of crust. The first one of the dry land of the continents consists mostly of granite and other light silicate minerals while the ocean floors are made up mostly of a dark and the dense volcanic rock known as the basalt.

The crust, which is the continental one, averages some around 25 miles that is 40 km thick. Which is although it can be thinner or thicker in other areas. The crust of the ocean is usually only about 5 miles and is 8 km thick.

Also read: NCERT notes on Structure of the Earth

Earth In Solar System 

It was around five billion years ago. There was a giant cloud of matter in our own galaxy and there was a Milky Way. which was condensed under its gravity which was exploding in nuclear fusion.

This fusion is released in what we call it as the sunshine. It is said to be very, very, very hot sunshine. It drew in most of the matters that were surrounding but some escaped. And some of this material was generally clumped together that is settling into a protoplanetary orbit.

The heat which was intense from the young Sun drove away most of the lighter elements that were hydrogen and helium that was 99% of the leftovers .

These eventually were condensed to form the gassy outer giants that are Jupiter, Saturn, Uranus, and Neptune.

There were the tiny bit of heavier elements that made up the rockier planets that are Mercury, Venus, Earth, and Mars.

Over millions of years they gradually shaped themselves into solid planetesimals and also later protoplanets with their own orbits that were unique.

Our Solar System spun into many different places.

Study the NCERT Notes Geography on Earthquake here.

Satellites Of Earth

A satellite that is natural or we say is in the most common usage an astronomical body that usually orbits a planet or minor planet or sometimes it is another small Solar System body.

The IAU-listed dwarf planets are also called to have natural satellites: that is Pluto, Haumea, Makemake, and Eris.

As of 2018 september there are 334 other minor planets called to have moons.

The artificial satellites are said to be the human-built objects which are orbiting the planet Earth and other planets as well in the Solar System. This is said to be different from the natural satellites or moons that orbit planets, dwarf planets and even asteroids. The artificial satellites are used to study the Earth that is other planets to help us communicate and at times even to observe the distant Universe. The satellites can also even have people in them like the International Space Station and the Space Shuttle.

The planet earth’s natural satellite is one in number and that is the moon.

The artificial area: the first occurrence of a satellite that was remote sensing can be dated to the launch of the first artificial satellite that was the Sputnik 1 by the Soviet Union on October 4, 1957. Sputnik 1 sent back radio signals which scientists used to study the ionosphere layer at that time.

Check the NCERT Notes Geography on Volcanoes here.

Sun And Earth

It took about a lot of years for the planet earth to form and then later settle into orbit around the star that is the sun. But how do we know that we can ask this question?

These questions usually plague and burn astronomers for millennia.

To study the movements that were of heavens back then we would look up into the sky. we would see the stars and the Sun which revolve around the very spot where you were standing the planet Earth. Through these revolutionary findings which were made or discovered, geocentrism began to crumble.

In the late 1600s sir Newton developed his three laws that were the basic laws of motion and the theory of universal gravity by combining physics, mathematics, and astronomy as well. These ideas laid the foundation for our current understanding of the planet Earth and the cosmos as well and helped astronomer Edwin Hubble construct the modern-day Big Bang theory.

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