Most of us have at least once in our life experienced the unpredictability of the weather. When the heavens start pouring over the city and lightning flashes across the sky followed by the sounds of thunder? Yeah, it’s intentional that I wrote thunder follows lightning and not the other way around. What? You’ve never noticed that? Well if you did then have you ever wondered why is it that we always see that bolt of lightning flash across the dark sky before we hear the growl of thunder? In simplest terms, it’s because the speed of light surpasses the speed of sound by almost 900,000 times. For decades now Man has been dreaming and trying to find ways to make travel at the speed of light possible but given how fast it is, Will humans ever be able to achieve it? Or will it remain a distant dream?
What is the Speed of Light?
Light is a kind of radiation. It falls between the infra-red and ultraviolet radiation bands and has a wavelength ranging from 400 – 700 nm. Light or visible light as it is labelled on the electromagnetic spectrum is contained in high energy packets called photons. Photons are massless particles that have energy, momentum and they travel with a speed/velocity. In vacuum (i.e. a space with no matter or in which the pressure of opposing forces is so negligible that it does not affect any chemical or physical process which is carried out in it.) light travels at the speed of ~ 300,000 km/second or ~186,282 miles/ second.
We know that’s a lot of zeros to precisely understand the nature of light’s speed. For the sake of understanding, if you hypothetically assume that you are seated in something that travels at the speed of light, the vehicle will be able to circle the earth 7.5 times in just 1 second. Crazy isn’t it? In practice though, nothing has yet even remotely reached the speed of light in making its way from point A to point B. Even though the phenomenon of light is largely studied under the domain of physics it does have its applications in other sciences too.
For instance, the first person to measure the speed of light was a Danish Astronomer by the name of Ole Romer who stated that light took almost 22 minutes to travel from the Sun to our Earth. With later experiments and observations of light’s transit with respect to different celestial bodies like Sun, Earth, Jupiter and the moons of both earth and Jupiter modern science believes that light from the sun takes only 7-8 minutes to reach our planet of residence.
Einstein and Relativity
Most of us might have heard this man’s name more than once but how many of us actually know about who he was or more importantly what difference he made to the world of science and especially modern physics? Before we come to his work let us first discuss who Einstein really was.
Who was Albert Einstein?
According to Britannica, Albert Einstein was born in the 3rd month of 1879 in Ulm, Germany. From a very young age, Einstein was a thinker who was curious about how things work rather than just focusing on what they were (i.e. the facts). At the age of 5 it is said that his father gave him a compass and the young boy became mystified with the fact that no matter which direction he moved the compass in, the needle (as if by some invisible force) would always point towards the north. His second wonder endeavor began when he discovered a book on geometry,
Albert was absolutely fascinated with the subject. Although Einstein did run away from boarding school, he was no dropout. He attended the Eidgenössische Technische Hochschule, or “Swiss Federal Institute of Technology in Zurich which has enjoyed the status of a university since 1909. He graduated with a degree in physics but struggled to find a proper teaching job for the subject. During his struggle and his work as a clerk, he often found time to wonder about nature and natural phenomenon. It was during that time while travelling on a train, that he came up with the idea that all objects travel at a speed that is relative and not absolute.
His major works include:
- Redefining the Nature of light and what it was made of
- Proving the existence of atoms
- Theories of relativity especially special relativity which proved that space and time were connected.
- Coining the infamous equation that stated that energy and mass were equivalent (conditionally).
Theory of Special Relativity
- E= energy
- M= mass
- C= speed of light in vacuum
One of the basic things that Einstein wanted the world to deduce from his equation was that energy and mass are different or interchangeable forms of the same thing. He proposed that if anything travels at the square of the speed of light, all of its mass will be converted to energy. When any amount of mass (out of the total mass of the said object) is converted to energy, the resulting energy would, by definition, move at the speed of light.
Postulates of the Theory of Special Relativity
Einstein’s theory of special relativity had two major postulates which are as follows.
- The laws of physics are the same in all inertial reference frames.
- The speed of light is the same in all inertial reference frames and is not affected by the speed of its source
The theory was initially known as the theory of relativity until Einstein himself added another dimension to the study of the motion of objects. He expanded the theory from objects moving at constant or zero velocity (special relativity) to objects moving with a certain acceleration (general velocity). The later also brings in the concept and effect of the force of gravity.
Understanding the Concepts
- Time dilation: the faster you go through space the slower you go through time. In other words, as speed increases time slows down so theoretically, if an object could move at the speed of light (which is the maximum speed known to man) then the concept of time (as we know it would cease to exist i.e. events would occur instantaneously. Of course, all of this is only theoretical, as yet.
- Length contraction: according to the theory of special relativity, when objects move faster they undergo a phenomenon called length contraction, as the name implies this would mean that as objects (you may assume a taxi or a spaceship) pick up speed their length compresses slightly.
Can we Travel Faster than the Speed of Light?
If the question must be answered in a single word then it would be, No! Not only has technology failed to make the concept a reality but scientific theories and laws defy the possibility. The concept of speed of light might be imperative to understanding numerous other phenomena and speed of objects may often be measured as relative to the speed of light but the practicality of actually reaching that speed is not just physically but biology far fetched and seems almost impossible (we say almost because we never know what science may come up with tomorrow or the day after).
According to the laws of physics, as an object picks up speed its mass increases. As we know from the law of inertia that the heavier an object is, the more energy it is required to move or stop the said object. Therefore, at increasing speed, if the mass of an object increases so does the energy that is required to move it. At the speed of light which is the maximum speed the mass of the object, in this case, the human (and probably the vehicle carrying him/her) would be so much that it would be impossible to gather the energy required to move it without causing an explosion (of much higher magnitude than even an atomic bomb).
Despite all the skepticism scientists may dream of making objects travel at the speed of light but replacing the objects with humans is an even more far-fetched idea than the former. You see a human body undergoes thousands of chemical reactions every second in order to sustain itself. With the whole idea of time dilation and clocks slowing down, the precisely timed reactions of the body will all be disrupted and given the delicate balance on which the human body operates it is highly unlikely that it would be able to survive such drastic change(s) of the environment.
Another possible implication might be that like everything else (mass of spaceship etc), your body mass would also increase if you travel at the speed of light, an increase in body mass would mean that all organs and fluids in your body would be heavier and it would be harder to push those fluids through the vessels and cells. Take blood, for instance, increased mass of blood will make it difficult or even impossible for our heart to pump it and thus you may die due to lack of oxygen if you manage to survive everything else.