Costing more than nine billion US dollars, the Large Hadron Collider (LHC), near Geneva, is the most expensive scientific experiment ever built.

Lyndon Evans, project head of the LHC, calls it a discovery machine, as “we do not know what we are looking for”. He was speaking at a special lecture at IIT-Madras on Wednesday to mark the launch of ‘Shaastra 2010'.

On March 30 this year, the first planned collisions took place inside the particle accelerator. The LHC is expected to answer many fundamental questions about the origin of the universe and our place in it.

Due to the high energy collisions that can be orchestrated inside the 27-km long tunnel which forms the LHC's accelerator chamber, Dr. Evans says: “We are now having our first peep into the state of the universe a mere microsecond after the big bang.”

According to him, the LHC will attempt to answer three fundamental questions. The first is the mystery of mass. All objects in the universe have mass. Gravity arises due to interaction between particles that have mass. Without gravity, galaxies and planets that support human life cannot exist.

Scientists have long predicted the presence of a background field called the Higgs field which interacts with particles to give them mass. “As we get closer and closer to the big bang by accelerating particles to high energies, we might be able to observe the Higgs boson,” says Dr. Evans. As it is so fundamental to the formation of the universe, it is called the ‘god particle'.

The second question will be the issue of matter and anti-matter. While both are equally likely to exist according to the laws of physics, the universe is filled with matter. Somehow, in the first few seconds after the big bang, conditions tilted in favour of matter particles. “Our very existence is the result of a broken symmetry,” he says.

The third question is the greatest puzzle in the field of cosmology. Showing a slide that listed what constitutes the visible universe, Dr. Evans said that 96 per cent of it is made of dark matter and dark energy. Of the remaining four per cent, 0.4 per cent is made of stars and the remaining 3.6 per cent is galactic dust. Centuries of scientific discoveries have led us to understand and explain only four per cent of the universe. “It is very humbling to put the galactic pie-chart together,” says Dr. Evans.

“When you find anything you do not understand, follow it. It might just lead you to a Nobel prize”, he told the large gathering of students. Terming the LHC the United Nations of science, he said scientists will keep looking for those elusive answers.

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