Diego Maza Ozcoidi, Professor of department of Physics and Applied Mathematics of the University of Navarra
The beginning of the journey to the frontiers of the Universe
Imagine a flea jumping on a trampoline. And not just any trampoline, but one capable of withstanding even a group of elephants without breaking. Although the analogy may seem ridiculous, it conveys an approximate idea of how strong and tense the fabric from which the trampoline is constructed must be and, above all, how ridiculous it is to imagine that we could perceive, from its periphery, the flea's jumps. Well, some scientists without fear of ridicule, and after years of effort, managed to detect the flea, and this, transferred to the universe, is what has been recognized by the Nobel Prize in Physics 2017.
To further develop the analogy, we could assume that the fabric of the trampoline represents the universe. That fabric must be very taut, for our senses perceive it as something imperturbable that has remained so forever and ever. Those same senses tell us that the events that occur on it, what we commonly call time, are completely independent of the existence of the fabric, and so we imagine them as independent of each other.
However, the reality is quite different: time and space are two inseparable manifestations of the same reality, which we generically call nature. In such a way that if we disturb one in any way, the other cannot avoid being affected, since we are talking about a single reality.
As already mentioned, the fabric is very tense. We would need a great amount of energy to disturb it, as much energy as that released by two suns colliding, and in doing so, the wave released in the collision deforms the very space through which it travels, so that it alters the measurement of time in those places it passes through.
On this principle, LIGO and VIRGIN - as the devices responsible for determining these disturbances are known - are able to detect that such waves exist. Also, since the measurement of time is affected by the passage of the wave, two clocks in different places should detect a small time lag if one of them encounters the wave at a given instant. This time lag is actually very, very small. Much smaller than a flea on a trampoline. That is why clocks must be replaced by laser interferometers: the only instruments capable of measuring such tiny time differences.
However, this very small time difference implies, despite its small size, an infinity of possibilities. Unlike finding of the famous Higgs Boson, in 2013 - which finally closed a model- LIGO and its "brothers" are just the beginning; the beginning of a new adventure in this journey to the frontiers of the universe.