Can there be life if Earth was a few meters away from its Star?

Scientists are looking alternate heavenly bodies which might support human life. There are numerous factors that are essential for declaring a place safe for human existence. Some of them are the presence of water, appropriate temperature, solar radiations, and a balanced mixture of gases. In case of Earth, all these things are fulfilled and it all comes down to a major factor which is the distance from the Sun. A lot of people claim that Earth is at an optimum distance, with respect to habitability, from the Sun and that’s the reason why life is possible on this planet alone. There is absolutely no reason to believe this claim.

The use of the term ‘optimum’ is inappropriate here as there are no other worlds to compare. We can say that Earth lies at a good enough distance to support life but being optimal gives a totally different meaning to it. The habitable zone around a star is known as the ‘Goldilocks Zone’. It refers to an area where the temperature is just right for the water to flow in the liquid state.

Although the location of the Earth has a huge part to allow habitation on its surface, it is far from optimal. The Goldilocks Zone of the Sun is about 1AU and the Earth lies in the innermost 1% of it. If Earth was located anywhere in the outer 99% of the Goldilocks Zone, it is quite possible that it would have a longer period of habitability. The reason for this is that stars like the sun steadily increase in brightness as they grow old. Due to this, the inner parts of the habitable zone migrates outwards. It is estimated that Earth will move out of that zone within a billion years. This will bring an end to all forms of life on this planet as the conditions will become too hostile for our survival.

Liquid Water is the most important commodity for our survival. Professor John Webb of the University of New South Wales acknowledged that and said.

“The only life we know about is our carbon-based life, and water plays a crucial part in our own existence, and so it’s only natural that we direct our attention to planets in locations capable of having liquid water. There’s plenty of life on Earth and there’s plenty of water, but we’ve yet to find life on other planets even in our own solar system.”

Having said that, there are several other Goldilocks factors on Earth that contribute to the emergence of a species as intelligent as humans. Some of them are listed below.

·         The atmosphere and Chemical Composition

A balanced atmosphere is a necessity for life to exist. Similarly, the chemical composition and density of the planet is also very important. For example, Martian atmosphere is very thin and as a result, abundant life on the red planet is not feasible. Contrary to that, the atmosphere of Earth is rich in gases like oxygen.

·         Temperature Consistency

Moderate temperatures help a variety of life forms to survive and flourish. Climates that are either too hot or too cold are hostile towards most of the organisms. The distance of Earth is just about right as the average temperature on our planet is 15^oC. Our immediate neighbors are Venus and Mars and their average temperatures are 462^oC and -60^oC, respectively.

·         Effects of Moon on the Earth

You might find it astonishing but without the moon, the average duration of a day might reduce to 4 hours. This simple fact is enough to explain the degree of stability our planet gets from its moon. According to a theory, the tidal action caused by the moon have encouraged evolution as animals living on the shore of the water bodies became accustomed to both land and sea.

·         Ozone Layer

We start learning about this amazing shield of nature from a very early age in our science classes. It is a buffer in the atmosphere of Earth that saves us from dangerous solar radiations like ultra-violet rays. A lot of planets have dense environments but the presence of ozone and its effective working is most likely a rare and unique phenomenon.