Physics, to borrow a phrase from Rumsfeld has “known unknowns” as well as “unknown unknowns”. Established theories like the Standard Model predict the existence of undiscovered particles like the Higgs Boson. There is also the dark matter problem — a major discrepancy between the amount of matter that should be in the universe and what has been observed.
Many unknowns originate at the instant of creation itself. The Big Bang itself is shrouded in mystery. Before the Large Hadron Collider (LHC) was up and running, it was impossible to recreate the initial conditions at the time of, and immediately, after the Big Bang.
The LHC can recreate some of those conditions. The 28-km sized artefact smashes particles together at 99 per cent of light speeds in temperatures near absolute zero. These collisions release titanic energies. Some of that energy is transformed into particles, which are rapidly transformed back into energy again. By observing those collisions through six specialised detectors, scientists can test existing theories and develop new insights.
After being out of commission for more than a year, the LHC relaunched operations last Tuesday. It is scheduled to run continuously for the next 18-24 months. The restart was at half-power but it has already set new records by generating collision energies of 7 Tera Electron-Volts. At full power, the LHC will generate 14 TEV or more, with hundreds of millions of collisions per second.
The energy released could create particles that have not existed since instants after the Big Bang. It may be possible to detect the Higgs Boson, an elusive creature postulated to impart mass to everything. The theory of super-symmetry suggests that an entire class of new super-symmetric particles (“sparticles”) could be found, thus explaining the paradox of dark matter.
Even more speculatively, string theory suggests the existence of spatial dimensions beyond the familiar three. The LHC may be powerful enough to kick matter into those, if they exist. Also, microscopic black holes may be formed but these would only last moments before being dissipated.
One good thing about the long hiatus was that it allowed time for doomsday theories of black holes swallowing the earth to be raised, digested and dismissed. A German court threw out an appeal for a stay order against the LHC.
Oddly, for pure science, it has captured popular imagination. A TV serial, several science fiction stories, a Dan Brown thriller and a popular rap number (composed by a CERN employee) are centred on the LHC. CERN has even contributed with regular chatty updates about the science and the fiction.
In the first three and a half hours after its relaunch, the LHC generated enough data to keep academics busy for a month. Assuming it stays functional, it will stretch the boundaries of global computing power as it churns out 30 petabytes of data in the next two years. (1 petabyte =1.024 million gigabytes). The challenges of keeping it functional are almost as large as the engineering effort required to build the facility.
The LHC will certainly make a large contribution to the sum of knowledge about known unknowns. But everyone of the 10,000-odd scientists collaborating in the experiment must be hoping fervently for a breakthrough into the realm of unknown unknowns. Some completely new unanticipated results could arise from the collisions and those could change current cosmology.