Has Faster-Than-Light Travel Already Been Invented? | Unveiled

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Has Faster Than Light Travel Already Been Invented?</h4>

According to Einstein’s theory of special relativity, nothing can exceed the speed of light - which is about 671 million miles per hour in a vacuum. The laws of physics decree that particles with mass would require infinite energy to obtain the same velocity. Nonetheless, some argue that travel beyond the speed of light could one day become possible - and may even already exist. 

This is Unveiled, and today we’re answering the extraordinary question: has faster than light travel already been invented?  

For most of human history, we didn’t know for certain how light traveled. Was it moving instantaneously, or at speeds faster than we could detect? This debate began with the Ancient Greeks, and would go on right the way up until 1675. The 17th century brought about improvements in the experimental method of science, which in turn generated interest in seeing if the speed of light was measurable. One of the most notable scientific figures of this time period was Galileo Galilei, a pioneer of classical physics, who was the first to realize that mathematics played a vital role in understanding the nature of the universe. Describing the physical results of experiments in mathematical terms, he paved the way for the astronomers who followed him, such as Christiaan Huygens and Isaac Newton. Galileo is most famous for championing heliocentrism, improving telescope technology, and discovering the moons of Juputer. But he was also the first person to attempt to try and measure the speed of light. 

The experiment, carried out in 1638, consisted of measuring the delay between the uncovering of a lantern and the perception of its light by an observer less than a mile away. As one would expect, the experiment was inconclusive, since the speed of light is so fast that it would require tools capable of measuring microseconds. Galileo could not determine if light was instantaneous, but said if it were not then it must be extremely quick. Only a few decades later in 1675, astronomers Ole Christensen Rømer and Christiaan Huygens made the first ever quantitative measurement of the speed of light. 

Initially, Rømer was gathering observations of Jupiter’s innermost moon, Io. His original goal was to measure the eclipsing of Io by Jupiter, and determine an accurate value for the moon’s orbital period. After taking these measurements regularly for years, he eventually noticed that the intervals between eclipses would vary proportional to the distance between Earth and Jupiter. Rømer spotted that when Earth and Jupiter were at their closest, the eclipses would happen approximately 11 minutes earlier than expected, and the reverse was true when the separation was at its largest. There was no way the orbit of Io could be influenced by the distance from Earth, which brought Rømer to the conclusion that this phenomenon was due to the finite speed of light. He ascertained that it takes about 22 minutes for light to cross the Earth’s orbit. This estimate was used by fellow astronomer Huygens to calculate the speed of light to be just over 136,700 miles per second - about three quarters of the real value. 

The following centuries brought about a plethora of new and improved methods for testing and measuring the speed of light, giving increasingly accurate values. For example, in 1964 MIT researcher William Bertozzi accelerated electrons to a variety of velocities, and found that it was completely impossible to accelerate them beyond the speed of light. Finally, in 1983, an international commission set the speed of light as the value we use today, defining it as an explicit constant. 

In modern physics, the theory of light is fully formulated, and explains all light as being made up of photons - massless, bosonic particles. These particles compose not just visible light, but all forms of electromagnetic waves, including radio waves, microwaves, and x-rays. In a vacuum, all of these travel at the speed of light. According to Einstein’s theory of special relativity, conventional matter and energy are unable to travel faster than light, thus setting it as the universal speed limit for matter. The theory also asserts that the velocity of a photon will be constant irrespective of whether its source is moving or stationary. Imagine a train moving at several miles per hour. If a light is emitted in the direction of travel, the light will NOT move at light speed plus the velocity of the train, but will simply travel at the speed of light. This became a puzzling issue for Einstein, since it doesn’t make much sense when you initially come across the concept. Eventually, he came up with a monumental solution for this problem, reaching the conclusion that time slows down for an object in motion relative to an object at rest. This means if a clock is in motion, it will experience time at a slower rate than a stationary one.

So, why is it the case that nothing can travel faster than light? Well, according to Einstein’s equations, it would require an infinite amount of energy to propel an object with mass at light speed. As an object approaches lightspeed, time slows down… and at lightspeed, it would stop completely. And so too would the velocity of the object - thus creating a barrier that nothing in the universe can accelerate beyond. Surprisingly, Einstein’s theory of general relativity is technically compatible with objects moving beyond the speed of light. It’s just not physically possible for the aforementioned reasons.

Well, at least, it’s not possible for most things … There are a handful of exceptions in nature, but in a different manner than you would expect. Firstly, the Big Bang exceeded lightspeed. But this doesn’t actually contradict the claim that nothing can move beyond lightspeed, since it was not a physical object expanding, but instead the fabric of space itself. This also creates the effect of very distant galaxies appearing to recede away from us faster than the speed of light, since the emitted photons’ velocities combine with the universe’s expansion. Nothing in this scenario is actually moving beyond lightspeed: the galaxies themselves are moving away at an incredibly slow rate, but the space between us is expanding at a rate so significant that it appears otherwise.

As mentioned, the laws of physics state that accelerating beyond the lightspeed barrier is impossible. However, some hypothesize that there may exist a particle that always exists beyond the limit. These elementary particles are called ‘tachyons’, and currently only exist theoretically, but just barely, as they don’t seem to be compatible with a great deal of modern physics. Tachyons have also never been observed in nature. Nor has any particle that exceeds the speed of light. In 2011, CERN reported that they’d detected a tau neutrino doing so, but disappointingly, the result was due to faulty equipment. 

Wormholes might be another way of achieving faster-than-light travel. These are theoretical structures that can be visualized as tunnels with their ends at separate points in space-time. Based on Einstein’s field equations, they work completely within our understanding of physics. Currently, none have been observed in nature. Even if we did find one, it might not be a safe idea to go exploring the inside of one. 

The most promising method to travel beyond the speed of light is a theoretical warp drive, called the Alcubierre drive, proposed in 1994. The reason this is such a promising concept is that it doesn’t actually travel beyond the speed of light to enable faster-than-light travel, which is a bit confusing to wrap your head around. The main principle of the drive is that it contracts space in front of it, and expands space behind it, establishing a ‘warp bubble’ which thus enables above-lightspeed space travel. What’s inside the warp bubble is actually stationary - it’s the region the bubble is riding that is moving, making it so that the relativistic effects of time dilation and such don’t need to be considered. As things currently stand, there is no known way to create one of these drives, and also there’s no proposed method to escape from one once you’re inside it. It also demands the manipulation of dark energy and exotic matter, which are things that we don’t have a complete understanding of. 

On the other hand, one physicist, Harold White, thinks the invention of an Alcubierre drive could happen sooner than we might expect. In 2011, he released a paper titled “Warp Field Mechanics 101”, improving upon the concept’s plausibility significantly. Dr White leads a research team at NASA’s Advanced Propulsion Physics Laboratory, and in May 2021 announced that they may have found the correct method for a ‘chip-scale’ warp drive. Research is ongoing, so make sure to keep a lookout for any successes coming from Dr White’s experiments. 

So, to conclude, has faster-than-light travel already been invented? As things stand, humans have only done it successfully in science fiction. There may exist the possibility of distant alien civilisations that mastered faster-than-light travel millions of years ago, but this is a pretty far reach. Going beyond the universe’s speed limit is a feat many rule impossible. But there are a few individuals, such as Dr White and Dr Alcubierre, who are increasingly optimistic that we will reach it some day, potentially even within our lifetimes.