As you sit peacefully in the living room on a stormy winter night, enjoying the luxury of modern sophisticated life, has it ever occurred to you how lucky you are?
You drop something on the floor and you say that it is gravity. You see the flash of lightning and you realize that thunder will inevitably follow. Thunder and lightning do not scare you anymore. Think of primitive human beings and how nature must have puzzled and scared them, then think of what we nowadays take for granted.
The popular story tells us an apple fell from a tree and hit Sir Isaac Newton’s head; whether it fell on his head or not, that is not the issue. The most important fact in this story is that he did not take the apple’s fall from the tree for granted. The fall of the apple inspired him to think of the question of why objects fall to the ground and not move upwards, leading him to his famous theory of gravity.
Newton was not the first one to think of gravity though. Aristotle said that objects fall to the Earth because objects have the tendency to fall towards the center of the universe, and back then Earth was considered the center of the universe. Unfortunately, that theory did not explain why planets do not fall towards the Earth.
Copernicus thus proved Aristotle’s theory to be totally wrong when he asserted that the Earth was not the center of the universe and that it is only another planet moving around the Sun. Newton states in his Universal Law of Gravitation that: Every particle attracts every other particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Every object in the universe is attracted to other objects; the force that attracts objects to one another is known as gravity. Gravity depends on the mass of the objects and the distance between them; it makes an apple fall from the tree because of its mass and the small distance and at the same time it keeps the Moon rotating around the Earth without wandering far off into space or hitting Earth.
Satellites are a good proof of how humanity benefitted from Newton’s theory. If scientists can measure the distance and decide on the suitable mass by which it becomes possible to make an object rotate around Earth without falling, such as the Moon, then they can definitely place satellites there that can be used for detecting weather changes or for communication.
Gravity had only puzzled people; thunder and lightning, on the other hand, scared them. Ignorant as they are of this phenomenon, imagine what people could have possibly felt. Some tales, or rather myths, that we nowadays find amusing were the ancients’ only way of explaining why some phenomena happen.
“Thunder and lightning”, writes Edith Hamilton, in her book Mythology: Timeless Tales of Gods and Heroes, “are caused when Zeus hurls his thunderbolt” (p. 19). In short, as Hamilton puts it, “Myths are early science” (p. 19).
Nowadays, science, of course, does not leave that phenomenon unexplained; lightening is an electric charge that occurs because of bad weather. In the sky, the friction between icy raindrops causes electrical charge; negative and positive charges attract each other, resulting in an electrical charge that reveals itself in the form of lightning. That electrical charge makes a huge noise that we call thunder; because light travels faster than sound, lightning is seen first, then thunder is heard.
The ancients’ fear of lightning is justified as it can strike and kill people. Now, when there is a storm, people are advised to stay indoors, to stay away from water, trees, metal objects, and not even take shelter in the highest object around.
Moreover, people nowadays can protect themselves from lightning by putting lightning rods on their houses. The lightning rod is a metal object that is used if the lightning hits the ground to transfer electricity from lightning harmlessly to the ground.
Primitive human beings were not blessed with knowledge; they were only left with phenomena that they could neither understand nor protect themselves from. The story of nature and mankind is a long one; it is a story that started with fear and ended with better understanding of nature. Next time you sit peacefully during a thunderstorm, think of scientists who never took phenomena for granted and who observed nature around them, searching for explanation, and be grateful for the knowledge they gifted us all with.
References
satellites.spacesim.org/english/function/index.html
http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html
http://www-spof.gsfc.nasa.gov/stargaze/Sgravity.htm
http://curricula2.mit.edu/pivot/book/ph0901.html?acode=0x0200
http://farside.ph.utexas.edu/teaching/301/lectures/node152.html
http://education.nationalgeographic.com/education/encyclopedia/lightning/?ar_a=1
Hamilton, Edith. Mythology: Timeless Tales of Gods and Heroes. Grand Central Publishing, n.d.
This article was first published in print in SCIplanet, Summer 2014 issue.
Cover Image by macrovector on Freepik.