by Prasad Ganti

The 2013 Nobel Prize in Physics was given to Peter Higgs of the UK and Francois Englert of Belgium for postulating a theory that predicted the Higgs boson. Nicknamed the “God Particle”, the Higgs boson is associated with the Higgs field that imparts mass to matter. The Higgs field exists everywhere, even in the vacuum of space. All matter weighs something due to the Higgs field, and the Higgs Boson acts as an intermediary. In 2012, evidence of the Higgs boson was found at the sophisticated Large Hadron Collider (LHC) at CERN, which accelerates protons to very high speeds using large amounts of energy.

The confirmation of this prediction follows the trend of past proposals and proofs. Let us consider Einstein’s General Theory of Relativity. Space becomes curved in the presence of gravity. Hence light, instead of travelling in a straight line, follows a curved path in the presence of gravity. The more intense the gravitational field, the more the bending. This leads to a black hole where gravity is so intense that light keeps bending and bending until it cannot escape out of the “hole”.

Arthur Eddington made a famous observation in 1919, which proved that the light does indeed bend in the presence of gravity. During a total solar eclipse, Eddington and his team measured the shift in position of a known star as it’s light passed nearby the Sun. The shift showed that the light from the star did bend in the presence of the massive Sun. The observation matched the theory perfectly, and Einstein became very famous for his “out of the world” theories. Einstein did get a Nobel Prize for Physics in 1921, but that was not for either the General or the Special Theory of Relativity. It was for the photoelectric effect, which is the basis for all the solar panels today.

Einstein’s General Theory of Relativity also predicts the existence of gravity waves. Massive and fast moving objects in the universe wrench the fabric of space-time and create these waves. Gravity waves should also exist from the time of creation of our Universe. None have been found so far. Will gravity waves to be discovered next?

There are two instruments built in the USA called LIGO (Laser Interferometer Gravity wave Observatory). One is in Louisiana, and another is in Washington State. Each observatory consists of two one-mile long arms constructed perpendicular to each other with laser beams running through them. When a gravity wave hits, it will change the length of one arm and cause an interference pattern. It has not happened so far. Probably the instruments are not sensitive enough to detect the waves or the Earth is obstructing the waves.

Two very sensitive instruments may be built in space using the same interferometry principle. One is called LISA (Laser Interferometer Space Antenna). Three satellites with very sensitive instruments will be positioned at the vertices of a large equilateral triangle. Each side of the triangle will be about a million miles long and positioned between the Earth and the Sun. The project is very expensive and funding is not committed yet. A competing cheaper version based on an atomic interferometer is being considered but is not funded either.

In these days of shrinking space budgets, neither of these projects may take off, but let us hope for the best that some day gravity waves will be discovered! Someday before I die, I would like to pen an article on the discovery of gravity waves!