The speed of light in a vacuum is just under 300 million meters per second. A massless light "particle," a photon or any electromagnetic radiation for that matter, cannot travel faster than 300 million meters in one second; in fact, nothing in this universe can. Consequently, given conventional physics, information cannot travel faster than the speed of light in a vacuum either.
The maximum velocity in the universe is an important constant in science. It is usually denoted by the letter "c," stemming from the Latin word celeritas, meaning quickness. Einstein drew heavily on this unwavering maximum physical speed while formulating his theories of relativity. Similarly, physicists Albert Michelson, Edward Morley, and Ernst Mach used c to help dispel the theory that light needed a medium through which to travel. In fact, all electromagnetic radiation readily passes through a vacuum.
It is important to note that c represents the speed of light in a vacuum. Simply proclaiming nothing can travel faster than the speed of light is not only vague, but inherently inaccurate. Light can indeed bend, curve, and be slowed by matter. The speed of light in air, in water, or through glass is slower than the speed of light in a vacuum.
Since light can be slowed, particles with mass can actually travel faster than light in some instances. This phenomenon is called Cherenkov radiation, which usually occurs in nuclear reactors where light is slowed down by water, but highly energetic electrons are less impeded. One might assume the terms "superluminal" or "faster than light (FTL)" apply here, but in reality they only apply to velocities quicker than c.
For the past several decades, data transmission through radio waves or through copper wires has dominated the communications industry. Radio and television signals are both regularly transmitted via wireless radio signals. Computer data, cable television, and telephone signals have mostly been transmitted through copper wires (CAT4, coaxial, et cetera.). Electrically speaking, copper wires work by transferring electrons between copper atoms. This method works, but many factors in the wire itself contribute to slow rates of electron transmission and signal infidelity. Radio waves, on the other hand are subject to interference and limited ranges.
Fortunately, a not-so-modern alternative is finally on the horizon for consumers. Fiber optics is rapidly replacing previous forms of data transmission. First invented and implemented in the mid-1800s, the field of optic data transmission has come a long way. Given our shrinking world and our ever-quicker computers, the limits imposed by conventional data transfer don't cut it anymore.
Fiber-optic communications offer much higher data transmission rates. Many providers are advertising Internet, television, and telephone services that operate at "the speed of light." That phrase is alluring, but don't be fooled: An optical fiber is not a vacuum, so light can only travel through one at about 70 percent the value of c. Even so, 70 percent c is much faster than the alternatives. Optic communications technology is finding a home in microscopic worlds as well. Supercomputers are beginning to incorporate optical signal pathways to transmit data along circuit boards, rather than relying on unreliable copper traces. The inclusion of optic signals comes hand in hand with the dawn of extremely quick computation rates. Computers have traditionally relied on copper to distribute clock signals throughout the system, which synchronize everything and dictate how quickly instructions are carried out. As clock rates move from the megahertz range to gigahertz, copper becomes less suitable for the job. Fortunately, light can easily distribute clock signals throughout a circuit board, supporting relatively high clock rates.
Even so, c must still be taken into account. Despite the small scale, with clock rates in the gigahertz (GHz) range, light can only travel so far per computing cycle. With a 1 GHz clock rate (one instruction is carried out every one billionth of a second), light can only travel about 30 centimeters, or about a foot. Modern processors are rapidly approaching 4GHz, and so it's clear that internal computer transmission media will soon become a hot topic.
Moore's Law predicts that computer complexity and power will grow exponentially. So far, the law has held true, leading scientists to speculate when and why we will hit a ceiling. Researchers have made incredibly advances minimizing circuits and packing astronomical amounts of computing power into packages smaller than a nickel - clearly that's not the limiting factor. At this point, it appears as though we may be actually be limited by the speed of light, c.
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