The time travel has definitely crossed most of our minds, thanks to the incredible images painted by sci-fi. But, have you ever thought of dialling up your past self even as you stay in the present?

No, we are not talking about some voodoo magic! Science is the magic in itself here and physics supports the theory of calling your past. All you need is something that can surpass the speed of light. Enter tachyons.

What are tachyons?

They are hypothetical particles, with negative mass, negative energy and speed faster than light. Albert Einstein proposed that their existence can affect causality (the relationship between causes and effects) paradoxically. Yes, we feel that our basic school lessons were lies too!

Einstein’s thought was followed by Arnold sommerfield in 1910 and later Richard Chace Tolman in 1917. The whole experiment “to telegraph into the past” is hence known as Tolman’s paradox.

But, how do they help in contacting your past self?

Theory of special relativity states that nothing can go faster than the speed of light. But if something does, it can travel backward in time. In this case, an “effect” would happen before the “cause” – for instance, a baby swinging before he gets a push. Didn’t seem so complicated when the flash did it.

Further, Gregory Benford, an American fiction author and astrophysicist, used theory to call a device that can telegraph the past; a tachyonic antitelephone. Although the current scientific knowledge does not support this device, but in theory, it is possible.

If somehow we do make the existence of tachyons possible, we would also have to rewrite the fundamentals of physics. Like Einstein mentioned, this could be ‘spooky’ and ‘hard-to-beleive’ and viable only if the hypothetical tachyon exists.