Space travel and other space related phenomena have always fascinated mankind towards them and thus has initiated space research and various programs to probably see these with a closure reference. Many theories and researches came along those journeys which made humans believe in the possibility of space travel or even time travel. Success if our mission to the moon and landing on it gave this dream a reality  and the mission to Mars gave further hope to travel to these planets. But there were also various other theories which came up to the existence of a multiverse and parallel universe which fascinated people . But to Reach these places we had to cross the barrier which Einstein gave in his Special Theory of Relativity . States that we cannot travel at speed light as it requires enormous amounts of energy since these places were some light years ahead of us. Which brought up the possibility of a Wormhole and various other theories related to it. It gave us the description of the shortest path which we can travel without breaking the rules of general relativity. 

But all this research brought us to the knowledge of particles which are believed to have speed equal to or more than that of light. These particles were named “Tachyons”. These are hypothetical particles which are believed to exist in our universe travelling with the speed faster than that of light. Since we know through general relativity that the speed of light is the highest speed which anything can have and travel with . The theory relates to the fact that “if any object is travelling initially slower than the speed of light, then it could not travel with the speed of light in any way possible”. It is observed in some smaller particles like photons which do travel with the speed of light and thus also always travel with the same speed. There must exist a possibility of particles which do travel with the speed greater than light and thus always travels at greater speed. 

Thus Tachyons can be considered as particles which have properties and characteristics different from the ones we acknowledge in our surrounding and our research work. This is because of their higher speed. So the main properties which may be present in these particles could be that “while solving the mathematical equation, the rest mass or the proper length or the proper lifestyle would be considered imaginary”. Confused. Let’s see an example. 

1.In special relativity theory, we get relative mass by the formula:

m= m°/√1-(v^2/c^2) 

Where m is the object in mass and m° is the rest mass of the object. Since in our case Tachyons travel with more speed than light thus v>c , we will get a negative number in the square root which gives us imaginary number i. So if we keep the rest mass as an imaginary number, both the imaginary terms get canceled out and we can surely find out the solution of the equation. Similar goes with proper length and life time.

2. Also it is believed that as the speed of tachyon I will increase, energy would significantly decrease as per the “Cherenkov radiation”. Cherenkov radiation is a process which tells us that when any particle is moving with the speed greater than light in any medium, it gives out blue glow which is due to interaction and thus it may lose energy. 

3. It is also believed that we can send messages to the past through Tachyons. 

“But as we see through many  researches, it shows that their existence is possible and thus could be present in our surrounding space. There are many physicists who believe that their existence may not be possible, as they raise different paradoxes . But as such no physical existence of such particles have been seen in any of the experiments conducted till date. So it makes them completely Hypothetical but with the belief to be detected soon, if they do exist”.