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2. Slowly simmer

Space, time, matter... everything originated in the Big Bang, an incommensurably huge explosion that happened 13.7 billion years ago. The Universe was then incredibly hot and dense but only a few moments after, as it started to cool down, the conditions were just right to give rise to the building blocks of matter – in particular, the quarks and electrons of which we are all made. A few millionths of a second later, quarks aggregated to produce protons and neutrons, which in turn were bundled into nuclei three minutes later.

Then, as the Universe continued to expand and cool, things began to happen more slowly. It took 380,000 years for the electrons to be trapped in orbits around nuclei, forming the first atoms. These were mainly helium and hydrogen, which are still by far the most abundant elements in the Universe.

Another 1.6 million years later, gravity began to take control as clouds of gas began to form stars and galaxies. Since then heavier atoms, such as carbon, oxygen and iron, of which we are all made, have been continuously ‘cooked’ in the hearts of the stars and stirred in with the rest of the Universe each time a star comes to a spectacular end as a supernova.

3. The mystery ingredient

So far so good but there is one small detail left out: cosmological and astrophysical observations have now shown that all of the above accounts for only a tiny 4% of the entire Universe. In a way, it is not so much the visible things, such as planets and galaxies, that define the Universe, but rather the void around them!

Most of the Universe is made up of invisible substances known as 'dark matter' (26%) and 'dark energy' (70%). These do not emit electromagnetic radiation, and we detect them only through their gravitational effects. What they are and what role they played in the evolution of the Universe are a mystery, but within this darkness lie intriguing possibilities of hitherto undiscovered physics beyond the established Standard Model.

4. The Large Hadron Collider

The Large Hadron Collider (LHC) is a gigantic scientific instrument near Geneva, where it spans the border between Switzerland and France about 100m underground. It is a particle accelerator used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionise our understanding, from the minuscule world deep within atoms to the vastness of the Universe.

Two beams of subatomic particles called "hadrons" – either protons or lead ions – travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists use the LHC to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very high energy. Teams of physicists from around the world then analyse the particles created in the collisions using special detectors in a number of experiments dedicated to the LHC.

The precise circumference of the LHC accelerator is 26 659 m, with a total of 9300 magnets inside. Not only is the LHC the world’s largest particle accelerator, just one-eighth of its cryogenic distribution system would qualify as the world’s largest fridge. All the magnets are pre‑cooled to -193°C using 10 080 tonnes of liquid nitrogen, before they are filled with nearly 120 tonnes of liquid helium to bring them down to -271°C.

At full power, trillions of protons race around the LHC accelerator ring 11 245 times a second, travelling at 99.9999991% the speed of light. Two beams of protons each travel at a maximum energy of 7 TeV (tera-electronvolt), corresponding to head-to-head collisions of 14 TeV. Altogether some 600 million collisions take place every second. The beams of particles travel in an ultra-high vacuum – a cavity as empty as interplanetary space. The internal pressure of the LHC is 10-13 atm, ten times less than the pressure on the Moon!