When we hear the term Earth, the first thing that comes up to our mind is that Earth is a planet where all forms of life exist; from basic living micro-organisms to highly sophisticated and intelligent human beings. Many factors are responsible for making Earth a suitable place for living.
Earth is the third planet in the solar system; the only object in the Universe known to harbour life. Earth formed over 4.5 billion years ago. Earth’s gravity interacts with other objects in space, especially the Sun and the Moon. Earth revolves around the Sun in 365.26 days, a period which is known as Earth year. During this time, Earth rotates about its axis about 366.26 times.
In 2000, palaeontologist Peter D. Ward and astronomer Donald Brownlee took the notion with their book “Rare Earth: Why Complex Life Is Uncommon in the Universe.” They argued that the odds of finding another living world in all the cosmos were severely unlikely. They called their idea the rare earth hypothesis.
Astronomers disagree on just how rare life is in the universe, but Earth nonetheless boasts several features that make it “just right” for life as we know it. Many reasons make Earth a suitable place for living.
Earth has a breathable atmosphere. Oxygen is the gas that is required for the life of most creatures. This is present in Earth’s atmosphere and also in water. Oxygen is constantly put into the atmosphere by plants and trees. Earth’s atmosphere also contains a small amount of carbon dioxide. This is a poisonous gas which makes up most of the atmosphere of planets like Venus and Mars and makes them unable to support human life. However, its smaller presence on Earth is useful as it helps to moderate the planet’s temperature and is absorbed by plants during photosynthesis to produce oxygen.
Water is considered to be the most important chemical necessary for life. Earth has water! Water is an excellent solvent, capable of dissolving many substances. It contains oxygen needed for life. Other liquids can contain poisonous elements. Water doesn’t burn the skin (like liquids containing acids do), it is drinkable, and it allows life-providing molecules to move around easily. Water on Earth is abundant and can be found in its three states of matter. It can be frozen, taking the form of ice. It can be liquid, seen in seas and oceans and lakes. It can also be a gas, seen as clouds.
The Earth has a slight tilt and wavers like a top as it spins, which can cause drastic shifts in climate over the course of thousands of years. But because of the moon’s stabilizing effect on our orbit, our climate is a lot more stable. Plus, the moon causes the tides, and some biologists think life began in tidal pools. Moon ensures climate stability by minimizing changes in planetary tilt. If our planet didn’t have a tilt, it wouldn’t have seasons. Likewise, a severe tilt would result in extreme seasons.
Earth is about 4.6 billion years old. The oldest known organism first appeared on Earth about 3.5 billion years ago, meaning that life might conceivably evolve in 1.1 billion years or less. However, more complex forms of life did take longer to evolve—the first multicellular animals did not appear on Earth until about 600 million years ago. Because the sun is so long-lived, comparatively, higher orders of life, including humans, had time to evolve. We’re here because our planet, Earth was tough enough to last until the first signs of life appeared.
“Heal the world, make it a better place, for you and for me and the entire human race. There are people dying if you care enough for the living. Make it a better place for you and for me.”
The Earth has a suitable climate for the existence of all forms of life because of a moderate amount of carbon dioxide, which is the driving factor for the survival of life forms. The temperature of planet Mercury ranges from 200°c below freezing to 375°c above. At 375°c, the water would only exist as a gas, and the planet would be completely dry. Venus has a surface temperature of 480°c, which would be much too hot for anybody to live in. Mars, although it can reach 25°c, is usually freezing and can be as cold as -140°c, a temperature which would freeze blood and water.
The cloud of gas and dust that eventually coalesced into the Earth contained enough radioactive elements to keep the core of the planet churning merrily for billions of years. Without that motion, there wouldn’t be a magnetic field at all.
All the reasons that are given above which makes Earth a suitable place for living is only possible because of one thing, the sun. If there was no sun, there would be no life on Earth. To put it simply, Earth probably wouldn’t exist either. Because of Earth’s ideal distance from the Sun, it receives the perfect amount of heat and light to allow life to be created and to support it. Imagine what would happen if the Sun suddenly vanished. How would we keep ourselves warm? How would we see? How would we get food and drink? How would plants and trees grow? How would they photosynthesize? Where would Earth go? The Sun’s gravity keeps Earth in its orbit, but if the Sun disappeared, Earth would simply float away.
Earth remains the only known planet to host life, due to a unique combination of factors. Earth contains all the ingredients and environmental necessities for life to emerge, plus the relative safety for it to evolve intact for hundreds of millions of years on end.