Scitech | New horizons for physics

The search for gravitational waves, dark energy, and time travel

A little over 100 years ago, a patent worker by the name of Albert Einstein came up with the theory of relativity, stating that the speed of light is constant and unattainable, and completely revolutionizing physics in the process. Great theories followed his work, and we now have a better understanding of black holes, the possibility of multiple universes, and the beginning of our own universe. Physics has given us the ability to develop technologies like GPS satellites and particle accelerators, but in many fundamental areas of study we have consistently failed to find the right answers and to devise equations that work all the time.

The theory of everything

By the 20th century, scientists were already on a quest to find a theory of everything. The discovery of the laws of electromagnetism by James Maxwell in the late 19th century, and the development of the special theory of relativity by Einstein in 1905 have encouraged scientists’ attempts to unify the laws of physics.

However, no such unifying theory has yet been verified. The strongest candidate – string theory – hasn’t yet been proven in an experimental setting and would require an atom smasher the size of the galaxy for us to test it.

What would a theory of everything serve? Its development would give us an enormous power to answer some of the oldest and most puzzling questions about the universe. What came before the Big Bang? Was there even such a thing as before? How many dimensions are there, and why can’t we see the higher ones? Such a theory might also be able to give us the basic tools to construct a wormhole, a hypothetical bridge in the curvature of spacetime that could give us the ability to travel back in time (but only to the point where the time machine was built) or help us make interstellar travel that exceeds the speed of light a feature of daily life.

The origin of the universe

Ultimately, the Big Bang is the holy grail of physics. It can unlock the final frontier of human understanding of the universe, and a lot has been going on in the last few decades to uncover these secrets. The real mystery, however – and the discovery that could bring us even closer to the moment of the Big Bang – are gravitational waves. Predicted by Einstein in 1916, gravitational waves are fluctuations in the curvature of spacetime, which propagate as a shock wave.

Matt Dobbs, professor of Physics at McGill, is trying to detect the trace of gravity waves left from the increased inflation in the beginning of time. His team is currently working on the EBEX project, which aims to send a balloon to the stratosphere in order to investigate for these traces, and try to push our picture of the Big Bang up until 10-35 seconds after the event. When asked by The Daily, Dobbs affirmed that these waves do in fact exist, adding that he’s hopeful they will be detected in the next twenty to thirty years.

Dark energy

A long-standing problem for physicists dating back to Isaac Newton is the inexplicable behaviour of gravity on a large scale. If the gravity force is always attractive, then why doesn’t the universe collapse into itself? This question was put to Newton by a priest, who believed that in order to maintain this “metastable” state the universe must be a gigantic clock, wound up by God at the beginning of time and obeying the laws of physics. Later on in the 20th century, the mechanical clock was replaced by a cosmological constant, an antigravity force pushing the stars apart. We now know this cosmological constant simply by the name of dark energy, which accounts for 73 per cent of the total mass-energy in the universe.

Finding the true nature of dark energy will reveal the ultimate fate of the universe – whether it will expand indefinitely until it freezes, or reverse the expansion and be crushed into itself.

However, for Dobbs, dark energy is one of the biggest unknowns, given that it is still a hypothetical form of energy. Dark energy also can’t explain anything about the initial state of the universe, because it first appeared at a much later time. One of the things that his research is trying to uncover are pockets of dark energy, by using large telescopes such as the South Pole Telescope, even if such methods presume gravity is exactly as described in Einstein’s general relativity. A slight deviation in our measurements of relativity might lead to fundamental change in theoretical physics, and the relativity equations might have to be modified, if possible.

But is the theory of general relativity wrong, and what would this mean for physics? According to Reg Cahill, professor of Physics from Flinders University in Australia, there are numerous sets of experiments that show the effects of changes in the speed of light. But such results are not yet recognized because for now, error probability in terms of measurement of the mass of Earth, the moon, or the sun, is inserted. Cahill explains this with the artificial creation of the dark energy concept, to account for the extra gravitation pull. If there are errors in relativity, this would effectively deal a great blow to dark energy. And mostly it would mean that that the laws of physics might have to be reworked, and that the last 100 years have given us a lot of unproven theories, but not enough solid ground to build on towards a theory of everything.

Whether we would be able to answer all of the fundamental inquiries about the universe is without importance in the face of the growing divisions within physics. A unification of gravity and quantum mechanics is needed in order to be able to answer the growing questions. Only then could we have as clear a picture of physics as Newton had, and start discovering ideas and inventions that could completely revolutionize our lives.

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