When people stand up and begin walking, they feel no pressure in an upward or downward direction. Sitting, walking, and running are exceedingly mundane activities. Yet each time people engage in such activities, they are completely unaware that they are resisting a very powerful gravitational force.
The most important reason for this is the size of Earth. If it were just slightly smaller, gravity would be far weaker, the planet’s atmosphere would fragment and disappear, and we would be unable to remain stable in the world. If the Earth were larger, gravity would increase considerably and various poisonous gases would make our atmosphere lethal. Even if we managed to protect ourselves from these gasses, we would be unable to move.
Yet such a problem never arises, because Earth’s size has been determined in a manner that makes human life possible. The conditions that combine are so delicate that there is no way even one of them could have come about by chance. Scientists have calculated the odds of such an event as 1 in 10123 [Roger Penrose, The Emperor’s New Mind (Oxford, UK: Oxford University Press, 1989); Michael Denton, Nature’s Destiny (New York: The Free Press, 1998), 9]. Clearly, the accidental formation of an environment suited to life is impossible.
Were Allah willed so, He could make each star and planet suitable for life, arrange matters so that human beings had no need to eat or drink, breathe gasses in specific proportions, or gravity or the Sun. But Allah, Who created all that exists, willed to bring together all of the astonishingly detailed conditions necessary for life to remind people that He created and controls everything and to give us the opportunity to appreciate His infinite might and turn to Him:
He to Whom the kingdom of the heavens and Earth belongs. He does not have a son, and He has no partner in the Kingdom. He created everything and determined it most exactly. (Surat al-Furqan, 2)