Why Life On Earth Is Possible? Our Unique Planet

  The Earth, our home planet in the Universe contains a wide variety of life with a huge complexity.It is the home of creatures in the deep oceans, the birds which roam across the sky, animals livings in forests and the insects living beneath the surface of Earth. Earth is the only known planet that can sustain life.Nowhere else life has been found yet.This variety of life on Earth have been made possible by various factors. Without these life on Earth could not have been possible. We will discuss them here.

Effects Of Distance From Sun

  The Earth lives in the habitable zone from the Sun, just far enough so that liquid water, the "universal solvent," can exist to create the chemicals of life. If the Earth were farther from the Sun, it might become like Mars, a "frozen desert," where temperatures have created a harsh, barren surface where water and even carbon dioxide are often frozen Solid. Beneath the surface of Mars one finds a permanent layer of frozen water.

  If the Earth were closer to the Sun, then it might become like the planet Venus, which is nearly identical to Earth in size but is known as the "greenhouse planet." Because Venus is so close to Sun, and its atmosphere is made of carbon dioxide, the energy of sunlight is captured by Venus. As a result, temperatures soar to 900 degrees Fahrenheit. Because of this Venus is the hottest and most hellish planet  in the solar system. This distance from the Sun played a crucial role in development of life on Earth.

The Habitable Zone

Effects Of Moon

  Our Moon is just the right size to stabilize Earth's orbit. If the Moon were much smaller, even tiny perturbations in Earth’s spin would slowly accumulate over hundreds of millions of years, causing Earth to wobble disastrously and creating drastic changes in the climate so as to make life impossible.

Without a large Moon (about a third the size of Earth), Earth's axis might have shifted by as much 90 degrees over a period of many millions of years. Since scientists believe the creation of DNA required hundreds of millions of years of climactic stability, an Earth that periodically tips on its axis would create catastrophic changes in the weather, making the creation of DNA impossible. The moons of Mars are not large enough to stabilize its spin. As a result, Mars is slowly beginning to enter another era of instability. In the past, astronomers believe, Mars might have wobbled on its axis by as much as 45 degrees. Fortunately, our Moon is “just right” in size to stabilize the orbit of Earth, so that such a disaster will not happen.

Size Of Moon as Compared To Earth

Effects Of Asteroids And Jupiter

 The presence of the planet Jupiter in our solar system is a fortuitous one for life on Earth, because its immense gravity helps to fling asteroids into outer space. It took almost a billion years, during the “age of meteors,” which extended from 3.5 billion to 4.5 billion years ago, to “clean out” our solar system of the debris of asteroids and comets left over from its creation. If Jupiter were much smaller and its gravity much weaker, then our solar system would still be full of asteroids, making life on Earth impossible, as asteroids plunged into our oceans and destroyed life. Hence, Jupiter too is just the right size to make life possible on Earth.

Effects Of Mass Of Earth

  The size of our planet is just right, which is suitable for life to exist. If Earth were a bit smaller, its gravity would be so weak that it could not keep its oxygen. The oxygen could not be contained in Earth's atmosphere. If it were too large, it would retain many of its primordial, poisonous gasses, which would make life impossible on Earth. Earth has "just the right" weight to keep an atmospheric condition beneficial to life. Also, Earth's magnetic field also play a crucial role in sustaining of life. Many of the radiation from space is deflected by its magnetic field, which makes it impossible to reach Earth. Without magnetic field, the radiation from space could have been destroyed life. 

Deflection Of Radiation From Space

Effects Of Distance From Center From Milky Way

  Earth also exists within the habitable zone of the Milky Way galaxy, about two-thirds of the way from the center. If the solar system were too close to the galactic center, where a black hole lurks, the radiation field would be so intense that life would be impossible. At this place in the Milky Way life could have been destroyed by radiation. And if the solar system were too far away, there would not be enough higher elements to create the necessary elements of life. 

Position Of Sun In Milky Way

 These were some of the conditions that made life possible on Earth.