Don't Cry UFO People, Extraterrestrials Cannot Break the Laws of Physics Either.

Greetings. The speed of light in a vacuum. 299,792,458 meters per second, or approximately 186,000 miles per second, or 671 million miles per hour. The speed limit of the universe, beyond which nothing with mass can travel. 

Thanks to the herculean efforts of the late Nobel laureate Albert Einstein (March 14th of 1879 - April 18th of 1955) we know far more about how the fabric of the universe works, including the intimate relationship between space and time and gravity. According to Einstein's Special Theory of Relativity, which was published in his 1905 paper "On the Electrodynamics of Moving Bodies," 'c' is the upper limit for the speed at which normal energy and matter can travel through normal space. The theory posits the two following ideas: 

1. The laws of physics are invariant (identical) in all inertial frames of reference (that is, frames of reference with no acceleration.) This is known as the principle of relativity. 

2. The speed of light in vacuum is the same for all observers, regardless of the motion of light source or observer. This is known as the principle of light constancy, or the principle of light speed invariance.

While admittedly a scientifically complex principle, a few aspects of the theory have direct influence on how humans, or any space faring species manages to tackle the challenges that space travel offers. With the universe being such a monumentally vast space, the distances between stars and planets are beyond the intellectual capacity of any human to comprehend. Logically, with such a speed limit at play, any journey to the stars is rife with roadblocks that simply cannot be overlooked or reasonably conquered. 

Take Proxima Centauri for example, the closest star to the Sun. Located in the southern constellation of Centaurus, Proxima Centauri is a small star of low mass approximately 4.265 light years distant from the Sun. If an interstellar spacecraft was capable of traveling at the speed of light, which we know is an impossibility, it would still take 4.265 Earth years to arrive and the same amount of time to make the journey back. In fact, the journey would take longer, since the spacecraft would have to slow down on its approach and slowly speed up when departing. When applying the Special Theory of Relativity to the scenario, the journey becomes far more problematic, and far less probable. As a spacecraft approaches relativistic speeds, the mass of the vehicle increases which means that more energy is required to maintain the vehicle's speed and gradual acceleration. As the spacecraft continues to speed up, its mass continues to increase and increase. Eventually, there comes a point when there is not enough energy in the universe to power the preposterously massive vehicle's speed. Obviously an impossibility. 

As a result of the aforementioned scenario, travel through normal space is restricted to far slower speeds than the light limit, greatly lengthening any attempts at interstellar travel. Such speeds, which are incredibly fast by human standards, are painfully slow in universal terms. Add the monumental distances involved, and interstellar travel becomes almost impossible. Only travel between stellar neighbors seems to be a possibility, albeit a remote one. In that scenario, spacecraft equipped for long, long journeys might be able to succeed, just a long as they don't too closely approach relativistic speeds. How does this apply to the UFO problem? The Special Theory of Relativity may, for the most part, eliminate the possibility of alien visitation via normal space, forcing other theories to the forefront; time travel, interdimensional travel, or other unproven unknowns. Do we know this to be true? No, but we do know that travel through normal space at the speed of light is an impossibility, with even relativistic speeds being extremely unlikely. Of course, the UFO subculture embraces possibilities like wormholes and travel via the use of black holes, but those beliefs are indefensible. Wormholes have not been scientifically determined to be a reality, and attempting to travel through a black hole would do wonders for your waistline, along with every other particle of your physical being. 

One final problem remains firmly attached to the table of considerations; the physical laws of the universe. The laws of physics are unbreakable and apply wherever and whenever you go in the universe, no exceptions. So the unsubstantiated speculations about how extraterrestrials allegedly travel vast distances to visit armed apes on an insignificant rocky planet orbiting an average main sequence star are just that; unsubstantiated speculations.

Don't cry UFO people, extraterrestrials cannot break the laws of physics either. 

Thank you for your time and consideration.