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Which Are the Origins of the Universe?A strong challenge for Big Bang: the ekpyrotic universe theory |
By Stefan Anitei, Science Editor
14th of August 2007, 11:10 GMT
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This is the root of Philosophy that haunted the human mind since Antiquity: which is the origin of the Universe? People tried to solve it in a simple way through religion, but there are still many unanswered questions.
The standard Big Bang model states that the universe emerged in a period of inflation started about 13.7 billion years ago. It exploded from a size smaller than an electron to its current size in less than one second.
First, it was all just energy, but some of the energy assembled into particles, which formed light atoms like hydrogen and helium. The atoms gathered into galaxies, then stars, inside which all the other elements formed.
This model satisfied the researchers investigating the sky, with its remarkable smoothness of space-time on large scales and the evenly placed
galaxies on opposite sides of the universe.
But some points show this is just another simple and maybe a bit rushed idea intended to make us feel comfortable.
First, the fact that the universe experienced rapid swelling early in its history cannot be checked, being based on the existence of supposed long gone energy forms in the original universe. "Inflation is an extremely powerful theory, and yet we still have no idea what caused inflation-or whether it is even the correct theory, although it works extremely well," said Eric Agol, an astrophysicist at the University of Washington.
"We've also learned there has to be dark matter in the universe, and now dark energy. So the way the model works today is you say, 'OK, you take some Big Bang, you take some inflation, you tune that to have the following properties, then you add a certain amount of dark matter and dark energy.' These things aren't connected in a coherent theory.", said Paul Steinhardt, a theoretical physicist at Princeton University.
"What's disturbing is when you have a theory and you make a new observation, you have to add new components. And they're not connected ... There's no reason to add them, and no particular reason to add them in that particular amount, except the observations. The question is how much you're explaining and how much you're engineering a model. And we don't know yet.", he added.
Steinhardt together with Neil Turok at Cambridge University launched a radical alternative theory to the Big Bang. The ekpyrotic universe theory claims that the universe emerged not just once, but by multiple times in endless cycles of destruction and rebirth.
Enormous cosmic "branes", representing stretches of the Universe, would collide once every trillion years, causing Big Bang-like events that re-fuel the Universe with matter and energy. This theory matches not just inflation, but other cosmic issues, too, like dark matter, dark energy and the ever-accelerating universe.
The ekpyrotic theory in fact speaks about an ageless and self-renewing Universe, more credible than the one supporting the definite life, a precise beginning and end.
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