EARTH AND UNIVERSE
- In the Solar System, our Earth is a unique planet because of the life forms that exist on its surface.
- Attempts to separate natural and anthropogenically induced variability in the Earth System have proved to be successful in many respects.
- our understanding of the natural dynamics of the Earth System has advanced greatly.
- It is now clear that global change is one of the paramount environmental issues facing humanity at present.
The Earth System
- Our Earth’s position is very special in the solar family.
- The Earth is placed at a distance from the sun that makes its position very conducive for the growth of living organisms.
- The recipe of life is unknown, but likely ingredients were methane, carbon dioxide, ammonia and water in the atmosphere and seas of the young Earth.
- The action of ultraviolet radiation or lightning could have combined these chemicals into amino acids, the building blocks of protein and of all living things.
- Plants were the first life forms to colonize the early Earth, followed by the proliferation of humans and other animals.
- These life forms are the biotic components of the Earth.
- The Earth has two motions.
- It rotates on its axis inclined at an angle of 23 ½0.
- Due to this rotation day and night occur.
- The Earth also on its inclined axis revolves around the Sun and thus produce seasons.
- The seasons are classified based on temperature conditions. In a year, there are spring, summer, autumn and winter seasons.
- The systems analysis helps to understand the Earth’s structure as a whole and also the functional interactions that exist between the components.
- The lithosphere, hydrosphere and atmosphere are the abiotic components of the Earth. These components interact with each other and create the fourth component of the Earth, the biosphere.
- Biosphere interacts with the abiotic elements and a number of ecosystems are created on the surface of the Earth. The Earth is considered a unique subsystem in the planetary system.
The Planetary System
- Gases and dust surrounded our star, the Sun approximately 5 billion years ago.
- Over time they condensed and formed planets.
- The planetary system consists of eight planets
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
- satellites
- All these planets revolve around the Sun on their own axes.
- Every planet has its own elements and mechanisms irrespective of their size.
- Mercury, Venus, Earth and Mars are smaller in size.
- They have large amounts of rocks and smaller amounts of gases.
- These planets are called rocky planets.
- Jupiter, Saturn, Uranus and Neptune are bigger in size.
- They have small amounts of rocks and large amounts of gases are called Gaseous Planets.
The Solar System
- The Sun is the main source of energy for the planetary system.
- The Sun is a mixture of gases.
- It consists of 92% hydrogen, 7.8% helium and 0.2% other gases.
- The temperature on the surface of the Sun is 6,000 degrees Celsius and the temperature at the centre of the Sun is more than 15,000,000 degree Celsius.
- The Sun shines as a consequence of the fusion of hydrogen into helium, which is constantly taking place in its core.
- Astronomers call the Sun a “Big Fire Ball”. Scientists believe that the Sun will cease its function when the hydrogen is exhausted.
- It is estimated that the Sun had enough hydrogen to burn for 10,000 million years (10 Billion years).
- It has burnt already for 5,000 million years.
- It is literally a middle-aged star.
- The Sun and its components namely the planets form the Solar System.
- This Solar System is a subsystem of the Universe.
- The Universe consists of millions and millions of galaxies.
- Solar System is part of one such galaxy known as the Milky Way.
- The universe is considered as a general system that consists of many subsystems. These components interact with each other and create the Earth’s environment.