UPSC Notes

1. The Crust It is the outermost solid pan of the earth. It is brittle in nature. The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental crust. The mean thickness of oceanic crust is 5 km whereas that of the continental is around

Every earthquake that happens is recorded by seismographs installed around the world. The records are analyzed to study the seismic waves. This understanding of waves is used to create an image of the structure of the earth’s interior even before drilling. All data collected by seismographs are stored in a computer at the central repository.

There are two different type of sources of information about the Interior. The first one is indirect information, which means that they show data in a way that gives us an idea about the Interior, but they don’t give direct measurements. These sources are useful in determining what might be inside our planet. The other

The origin of life on Earth is a controversial topic in the natural sciences. The current widely-accepted scientific theory about the origins of life on Earth is known as the nebular hypothesis, or simply out of equilibrium chemistry. Perhaps the most fundamental and at the same time the least understood biological problem is the origin

It is not very likely that the total amount of water at Earth’s surface has changed significantly over geologic time. Based on the ages of meteorites, Earth is thought to be 4.6 billion years old. The oldest rocks known are 3.9 billion to 4.0 billion years old, and these rocks, though altered by post-depositional processes,

The Lithosphere is the outermost layer of the Earth. The lithosphere is divided into two parts namely the crust and the uppermost part of the mantle. Our planet has an outer solid, rocky layer which has all its plates moving on top of it continuously. They are called tectonic plates. They are located under the

The earth has a layered structure. From the outermost end of the atmosphere to the centre of the earth, the material that exists is not uniform. This is because it has a layered structure. The materials found in these layers are not uniform in their composition and density. From the surface to deeper depths, the

The Moon is Earth’s only natural satellite and the fifth largest moon in the solar system. The Moon’s presence helps stabilize our planet’s wobble and moderate our climate. The Moon’s distance from Earth is about 240,000 miles (385,000km). The Moon has a very thin atmosphere called an exosphere. The Moon’s surface is cratered and pitted

Many of us have wondered what is our solar system structure, and why is it the way it is. There are eight planets orbiting our sun in a relatively stable and regular position. The planetary orbits have been set so as to produce a balance called the force equilibrium which helps to avoid collisions with

Early Theories The Nebular Hypothesis, originally proposed by Immanuel Kant was the first scientific hypothesis for the origin of the Solar System. The ‘nebula’ referred to is the vast cloudy interstellar medium that consists of gas and dust, in which new stars are born. This hypothesis considered that the planets were formed out of a