Giant neutrino detector built in USA to unravel the mysteries of the universe

Neutrinos are inconceivably tiny subatomic particles. Most of them (in the vicinity of Earth) come from the Sun, and there are an awful lot of them. 65 billion neutrinos pass through every square centimetre of the planet EVERY SECOND.

According to scientists at the U.S. Department of Energy's Fermilab, they can help us "understand the nature of energy, matter, space and time. Neutrinos could be key to explaining the origins of the universe."

Despite being a billion times more abundant than the particles which make up all known matter, they are incredibly mysterious. This is mostly because of their size and weakness - neutrinos interact so little with other particles that the vast majority of the time, they pass right through them; through the Earth itself.

Because neutrinos are so easily missed, scientists need to build one of the biggest detectors in the world. The Fermilab NOvA experiment in Minnesota will capture neutrinos fired from a cannon more than 500 miles away in a detector that weighs 14,000 tons. The neutrinos will pass through the Earth at depths of up to six miles beneath the surface, and travel the distance between the cannon and the detector in just under 3 milliseconds.

The detector is based in Minnesota, but the cannon is in Illinois. The detector is made up from 344,000 cells of PVC filled with a liquid substance known as a 'scintillator'. When neutrinos strike atoms in the liquid, a burst of charged particles is released, which can be measured on photo-detecting plates.

One reason the detector is so vast is that the beam of neutrinos spreads out as it travels, from a starting width of about 6 feet to several miles apart at the other end.

The experiment has to take place over such a large scale to allow the neutrinos to change from one type to another along their journey. Evidence for this shifting of states is rare, and if it could be observed, would go a long way to helping our understanding of what the universe is made of.

The change of neutrinos from one state to another - known as oscillation - could explain the reason the universe consists of more matter than antimatter - in other words, it could be the reason why we are all here.

Watch the video for more information on NOvA and what it could mean for us.