Dark 'phantom' energy maybe causing accelerated expansion of the Universe

Washington, Oct 22 : A team of cosmologists from the University of the Basque Country has determined that the accelerated expansion of the Universe can be explained by dark 'phantom' energy.

To explain the majority of the phenomena occurring in the Universe, complicated calculations with a computer are required and which have to be based on appropriate mathematical models.

This is what the Gravitation and Cosmology research team at the University of the Basque Country (UPV/EHU) is involved in: analyzing models capable of explaining the evolution of the Universe.

One of the phenomena that standard models of physics have not yet been able to explain is that of the accelerated expansion of the Universe.

Although Einstein proposed a static model to describe the cosmos, today it is well known, thanks to supernovas amongst other things, that it is, in fact, expanding.

By measuring the quantity of light that gets to us from a supernova, we can calculate its distance from us, and its colour indicates the speed at which it is distancing itself from us.

The more reddish it is, the faster it is travelling. In other words, comparing two supernovas, the one that is distancing itself more slowly from us is a more bluish colour.

According to observations by astrophysiscists, besides supernovas distancing themselves from us, they are doing so more and more rapidly, i.e. distancing themselves at an accelerated velocity, just like the rest of the material of the Universe.

The energy known to exist in the Universe, however, is not sufficient to cause such acceleration.

Thus, the theory most widely accepted within the scientific community is that there exists a 'dark energy', i.e. an energy that we cannot detect except by the gravitational force that it produces.

In fact, it is believed that 73 percent of the energy of the Universe is dark.

The unique characteristic of dark energy known to us is that it possesses repulsive gravitational force. That is, unlike the gravity we know on Earth, this force tends to distance stars, galaxies and the rest of the structures of the Universe from each other.

This would explain why the expansion of the Universe is not constant, but accelerated.

Such powerful dark energy is known as phantom energy, with which the Universe is able to expand to such an extent that the structures we know today would disappear.

This research group considers that the phantom energy model may be the most suitable to explain the accelerated expansion of the Universe.