Conventional wisdom on Earth currently views the ultimate speed at which objects can travel to be the speed of light. This was explained by Albert Einstein in his theory of relativity.
Speed of Light
This speed limit in terms of how fast objects, or more specifically, vehicles can travel presents a paradox for modern Earthlings. A lot of Earthlings want to believe that the large number of UFO sightings occurring around the planet mean that Extra Terrestrials exist. They want to believe these sightings are proof of beings transiting star systems and visiting our star system, and more specifically, our planet Earth.
There is a very basic problem that exists that gives people who disagree with this viewpoint a firm position to stand on that believers cannot refute. In order for a being to transit a star system and travel here at the speed of light, it would take more than four years to get here just from the closest star system Alpha Centauri. So a round trip would take over eight years.
Travel to star systems beyond that would quickly add up to longer than the span of human life on Earth, considering the vast distances of even the visible Universe. So travel through space at the speed of light does not seem plausible and holds the UFO phenomenon back from being solved.
To transit star systems UFO's would need to travel much quicker than the speed of light. In fact, the speed of light would almost be the entry speed or idle speed at which this travel would occur, similar to the way car and plane engines have an idle speed at which they operate at when turned on but is essentially the slowest speed the vehicle moves at when engaged. The speed of light would need to be the idle speed for a UFO because even at that speed it would be far to slow to make Interstellar travel plausible.
Currently, on Earth, there is a term for objects that travel faster than the speed of light.
Although Tachyons are only hypothetical, what is uniquely interesting is the term Tachyon itself. In linguistics, there are two terms which are used to break down, and or build up, or form new words. These are called portmanteau's and morphemes.
The easiest way to understand how to use portmanteau's and morphemes is to see them in use. For example, the word SMOG is a portmanteau of the morphemes SMoke and fOG.
SMOG = SMoke fOG
Using this linguistic tools you can break the word TACHYON down into TACH beYONd.
TACHYON = TACH beYONd
So the term Tach represents the speed of light and the term beyond means to travel faster than that.
So if the term Tach represents the speed of light we can then use familiar terminology from the aviation industry to describe movement in differing amounts of the speed of light. Mach One is a term which describes moving at the speed of sound. Faster than the speed of sound, aircraft move in what is known as Mach numbers.
Using Mach numbers as a standard for describing increasing speed levels in multiples of the speed of sound, you could use Tach numbers as a standard for describing increasing speed levels at the speed of light. For instance, Tach One then becomes the speed of light and Tach Two is twice that speed and so on.
So now there is a term which allows for discussions to take place which can facilitate the possibility for a UFO to transit a star system at any distance and arrive at Earth and return in a reasonable period of time. Most people will still simply believe it is impossible to travel that fast and refuse to believe it.
If you use the analogy of telling a cave man that Earthlings will one day travel in Mach numbers, he would be dumbfounded to even try to comprehend what you were telling him. That same scenario is what is dumbfounding modern day man. A present-day Earthling basically has the intelligence level of a caveman when compared to an Extra Terrestrial. You will have a better chance of having an Extra Terrestrial arrive on Earth and explain what is going on to the Earthling than to get them to understand, unless they are an extremely open-minded being.
The important observation here is that it will take modern day man quite a while to figure out how to engineer vehicles and transit star systems and travel at speeds in excess of Tach One. Yet, with the terminology in place, modern day man can now have conversations about the possibilities and simultaneously start to solve the UFO phenomenon.
The odds are far greater that Earthling man will comprehend visitation by Extra Terrestrials linguistically rather than his ability to scientifically engineer the reality physically. Or stated another way, it is far easier to envision they will arrive here on Earth far sooner than we will travel there in vehicles we design and build here on Earth.
Tach One = Speed of Light