WHAT MAKES THE EARTH UNIQUE????
Unlike the other planets of our solar system, life developed in to many forms on the Earth after its emergence. Liquid water and oxygen for breathing made this possible. Millions of species of plants and animals thrive today on land and water. Water covers more than two-thirds of the Earth’s surface. Therefore, the Earth appears blue from the moon or from the International Space Station. For this reason, it is also called the ‘blue planet’. Till now, scientists have not discovered life in any other place in the universe, but they believe that one day they will do so.
HOW WAS THE EARTH FORMED???
The earth, along with the sun and the remaining planets of our solar system, originated around 4.8 billion years ago from dust particles, which agglomerated gradually. At that time, the young Earth was bombarded by countless meteorites from space. The Earth ‘s interior was molten and volcanoes erupted constantly. But over millions of years, the Earth’s surface cooled down. Around 3.8 billion years ago, the temperature decreased to about 100*C and the Earth’s crust slowly started becoming solid. At this time the gaseous cover on the Earth was mostly made up of water vapour.
WHY DID LIFE DEVELOPED ON THE EARTH???
The origin of the life on the earth is fortunate series of events .The earth’s distance from the sun was such that its atmosphere and surface cooled down to a moderate level. Liquid water-and not just water vapour – also formed, and it did not freeze as the sun was not too far away. The cooling of the Earth gave rise to a kind of ‘primordial ocean’. The action of the UV rays of the sun, the lightning flashes produced by storms, and the countless volcanic eruptions gave rise to new complex chemical compounds. About 4 billion years ago the first molecules appeared, from which the first unicellular organisms are formed.
WHAT WOULD HAPPEN IF THERE WAS NO WATER ON EARTH???
Without water, there would be no animals and plants, which carry out photosynthesis and release oxygen, and consequently the oxygen content in the atmosphere would go down. Moreover, the absence of oceans would have serious consequences as they help to keep the Earth’s climate moderate by storing heat inside them. Without large water bodies, the temperatures of the sunlit areas and those way from the sunlight would change drastically. The temperature difference between day and night and between summer and winter would be very large. As a result, hurricanes would be a constant occurrence on the Earth.
DID YOU KNOW THAT????
•WATER IS PRESENT ON OTHER PLANETS AS WATER VAPOUR OR ICE, BUT NOT IN ITS LIQUID FORM.
•THE ‘BLUE-GREEN ALGAE’ ARE CALLED CYANOBACTERIA. THEY ARE AN EXCEPTION IN THE ANIMAL WORLD BECAUSE THEY CARRY OUT PHOTOSYNTHESIS LIKE PLANTS.
•MASS OF THE EARTH IS AROUND 6 TRILLION TONS, i.e., SIX FOLLOWED BY 21 ZEROES!