Write an article on earth day in 200 words.
Answers
Answer:
Explanation:
Earth is the planet we live on. It is the third planet from the Sun. It is the only planet known to have life on it. The Earth formed around 4.5 billion years ago.[28][29] It is one of four rocky planets on the inside of the Solar System. The other three are Mercury, Venus, and Mars.
The large mass of the Sun makes Earth move around it, just as the mass of Earth makes the moon move around it. Earth also turns around in space, so that different parts face the Sun at different times. Earth goes around the Sun once (one year) for every 3651⁄4 times it turns around (one day).
Earth is the only planet in our solar system that has a large amount of liquid water.[30] About 74% of the surface of Earth is covered by liquid or frozen water. Because of this, people sometimes call it the blue planet.[31]
Because of its water, Earth is home to millions of species of plants and animals.[32][33] The things that live on Earth have changed its surface greatly. For example, early cyanobacteria changed the air and gave it oxygen. The living part of Earth's surface is called the "biosphere".[34
Earth is part of the eight planets and many thousands of small bodies that move around the Sun as its solar system. The Solar System is moving through the Orion Arm of the Milky Way galaxy now, and will be for about the next 10,000 years.[35][36]
Earth is about 150,000,000 kilometres or 93,000,000 miles away from the Sun (this distance is called an "Astronomical Unit"). It moves on its orbit at an average speed of about 30 km/s (19 mi/s).[37] Earth turns all the way around about 3651⁄4 times in the time it takes for Earth to go all the way around the Sun.[4] To make up this extra bit of a day every year, an additional day is used every four years. This is named a "leap year".
The Moon goes around Earth at an average distance of 400,000 kilometres or 250,000 miles. It is locked to Earth, so that it always has the same half facing Earth; the other half is called the "dark side of the moon". It takes about 271⁄3 days for the Moon to go all the way around Earth, but because Earth is moving around the Sun at the same time, it takes about 291⁄2 days for the Moon to go from dark to bright to dark again. This is where the word "month" came from, even though most months now have 30 or 31 days.
Earth and the other planets formed about 4.6 billion years ago.[38] They were made of the leftover gas from the nebula that made the Sun. The Moon may have been formed after a collision between the early Earth and a smaller planet (sometimes called Theia). Scientists believe that parts of both planets broke off — becoming (by gravity) the Moon.[39]
Earth's water came from different places. Condensing water vapour, and comets and asteroids hitting Earth, made the oceans. Within a billion years (that is at about 3.6 billion years ago) the first life evolved, in the Archaean era.[40] Some bacteria developed photosynthesis, which lets plants make food from the Sun's light and water. This released a lot of oxygen, which was first taken up by iron in solution. Eventually, free oxygen got into the atmosphere or air, making Earth's surface suitable for aerobic life (see Great Oxygenation Event). This oxygen also formed the ozone layer which protects Earth's surface from bad ultraviolet radiation from the Sun. Complex life on the surface of the land did not exist before the ozone layer.
Earth's land and climate has been very different in the past. About 3 to 3.5 million years ago almost all land was in one place. This is called a supercontinent. The earliest known supercontinent was called Vaalbara. Much later, there was a time (the Cryogenian) when Earth was almost entirely covered by thick ice sheets (glaciers).[41] This is discussed as the Snowball Earth theory.[41]