In fact, Albert Einstein suggested gravity is not a force at all. New data from an experiment conducted within a kilometre of the South Pole could validate Einstein's approach since this shows how gravity worked just after the Big Bang. The identification of primordial gravitational waves by the Background Imaging of Cosmic Extragalactic Polarisation 2 (BICEP2) experiment at the South Pole is still tentative. But this could be as big a deal as finding the Higgs boson, in that it validates several fundamental hypotheses and rules out other ones.
Gravity waves are predicted by Einstein's General Theory of Relativity (1916) and also fit with Georges Lemaître's 1927 paper, which conceptualised the expanding universe ("A homogeneous Universe of constant mass and growing radius accounting for the radial velocity of extragalactic nebulae"). The BICEP2 data may also fit the "Cosmic Inflation" hypothesis, which suggests the universe expanded a huge amount in the first instant of the Big Bang.
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The early studies of gravity have become the stuff of legend. Galileo is said to have chucked balls of different masses off the Leaning Tower of Pisa. The balls landed at the same time showing gravitational acceleration didn't vary with mass. An apocryphal apple helped Newton realise that two bodies attracted each other by a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Sundry pendulum experiments measured gravity acceleration (about 9.8 metres per second squared at sea level).
In 1916, Einstein postulated gravity is a curvature of space-time caused by objects with mass. Think of space-time as a trampoline. If somebody jumps on it, the shape changes. The extent of deformation depends on mass. According to Einstein, gravity works like that. He also hypothesised that under certain violent circumstances, gravity would cause ripples in space-time and those gravity waves would propagate at the speed of light forever.
In 1927, Lemaître showed that the universe was expanding. He calculated the rate at which distant objects are receding (this is Hubble's Law because Edwin Hubble calculated it more accurately two years later). Lemaître's hypothesis was at odds with all earlier assumptions that the universe had always been there and was stable.
If Lemaître's equations are projected back in time, they lead to what Monseigneur Lemaître, a Jesuit Priest by vocation, called the "Cosmic Egg". Some 13-14 billion years ago, the universe was very small in volume, very hot and very dense. In fact, it must have been a singularity, until it exploded and it has since continued to expand.
Initially, Einstein didn't like the concept of an expanding universe. But the maths was impeccable and it did answer questions about the recession of distant objects. It also fitted with the General Theory of Relativity. The Big Bang (a pejorative nickname coined by Fred Hoyle who refused to accept the theory) was the kind of violent event, which would generate gravity waves. However, those waves would be very weak and almost impossible to detect.
Since the early universe was very hot, there would also be thermal radiation emitted as it expanded and cooled. This cosmic microwave background radiation (CMB) was discovered in the 1960s and it is strong evidence for the Big Bang. CMB is present as a glow across the universe. Like light, it polarises where it has been interfered with by matter, or gravity waves. Gravity waves deform space as they pass, causing CMB to polarise.
Around 35 years ago, the Cosmic Inflation hypothesis was developed. Physicists such as Alan Guth of MIT, and Andrei Linde of Stanford, suggested the universe expanded exponentially and instantaneously in the first fraction of a nanosecond after the Big Bang, and then continued to expand (different models suggest different rates). If Inflation occurred, it would make primordial gravity waves much stronger and easier to detect.
Enter BICEP2. This was an array of radio telescopes and polarisation detectors set up at the South Pole as a collaborative effort. The array was assembled at Caltech, involving scientists from several universities and institutions. BICEP2 examined CMB with the focus set on very small areas of sky. The experiment collected data through January 2010- December 2012.
After examining the results for over a year, the Harvard-Smithsonian Center for Astrophysics announced BICEP2 had found a pattern called primordial B-mode polarisation - images where the CMB formed swirling patterns. This could only be created by primordial gravitational waves. A successor to BICEP2, the Keck Array, has shown similar results. Further confirmation of data is required and there are multiple other radio telescope experiments looking for confirmation.
Assuming the results are correct, the signals were surprisingly strong. Inflation may have started even earlier than most models suggest (we are dealing in trillionth parts of trillionth parts of seconds here). Intriguingly, inflation models are quantum in nature. This could offer the first link between quantum phenomena and gravity. There are also useful implications here about the dark energy which is believed to sparked the Big Bang and about the heat signature of the first instant.
This is a huge fundamental breakthrough. It confirms many key details and has thrown up surprises as well. There is even the possibility this might lead to one of the holy grails of physics - a unified theory where the four fundamental forces can be shown to be aspects of the same force.