Unlike the other planets of our solar system, life developed into 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 in 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.
There are many factors that make Earth special and unique in the known universe. Here are a few:
- The presence of liquid water: Earth is the only known planet in our solar system with large bodies of liquid water on its surface. Water is essential for life as we know it, and the fact that Earth has so much of it is one of the reasons it’s such a special place.
- The right distance from the sun: Earth is situated at just the right distance from the sun to support life as we know it. If we were too close to the sun, the planet would be too hot for life to survive, and if we were too far away, it would be too cold. Earth’s distance from the sun allows for a stable climate and a range of environments that can support a diverse array of life forms.
- A protective atmosphere: Earth has a thick atmosphere that shields it from harmful radiation and other dangerous particles from space. This is due in part to the planet’s magnetic field, which helps to deflect these particles away from Earth.
- Plate tectonics: Earth’s crust is made up of a series of plates that move and shift over time. This has led to the creation of mountains, valleys, and other geological features that have helped to shape the planet’s surface over millions of years.
- Biodiversity: Earth is home to an incredibly diverse array of plant and animal species, from the tiniest bacteria to the largest whales. This biodiversity is a testament to the planet’s ability to support life and is one of the things that makes it so special.
Overall, the combination of these and other factors makes Earth a truly unique and special place in the universe.
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 develop on Earth?
The origin of life on the Earth is a 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 were formed.
Did you know that…
Water is present on other planets as water vapor 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.
The blue color of the Earth is due to the copious amount of water present on it? Water is actually transparent, but deep water bodies ‘absorb’ the red and yellow rays of light. Therefore, only the blue rays get reflected and reach our eyes.
Earth facts in figures
Average distance to the sun: Around 150 million km.
Radius: 6378 km.
Circumference: 40,077 km at the equator, 40,009 km at the poles.
Duration of one revolution around the sun: 365.26 days
Number of moons: 1
Mass of the Earth: Around 6 trillion tons, i.e., six followed by 21 zeroes!
Where does the oxygen we breathe come from?
Gaseous oxygen was created on the Earth about 3 5 billion years ago. At that time, the UV light of the sun decomposed the water vapour molecules present in the atmosphere, and released oxygen and hydrogen. But a major part of the oxygen immediately reacted with other substances, so that it was no longer avialable in the atmosphere as gas.
Oxygen was also produced by the seas, where the ‘blue algae’ carried out photosynthesis. These bacteria converted sunlight and carbon dioxide into energy. In the process, gaseous oxygen was released as a ‘waste product’, which accumulated in the atmosphere. About one billion years ago, about one-twentieth (4%) of the atmosphere consisted of oxygen.
What would happen if there was no water on Earth?
Without water, there would be no animals or 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 away 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.
Is there life on any planet other than the Earth?
There is no life on the other planets in our solar system because their environments are not favorable for life. They are either too hot, too cold, or too stormy. The only place that can be assumed capable of sustaining life is Europa, the moon of Jupiter.
Scientists say that an ocean of liquid water could be present on this celestial body under a 10-km thick layer of ice. They also say that civilizations like ours could be present – if at all – only outside of our solar system.