Article Posted on : - May 20, 2011

WASHINGTON (PTI): “Dark energy” does exist, and it's not Albert Einstein's "greatest blunder" in his theory of gravity, say planetary scientists.

"Dark energy" is a concept first cast by Einstein in his original 'Theory of General Relativity'. The scientist included the idea in his original equations but later ruefully admitted that it was "his greatest blunder".

Now, a survey of 200,000 galaxies by an international team, led by Dr Chris Blake of Swinburne University, has shown that "dark energy", responsible for expanding the Universe, is real and not a mistake in Einstein's theory of gravity.

Using the Anglo-Australian Telescope, the team of 26 planetary scientists contributed to the "WiggleZ Dark Energy Survey" which mapped distribution of galaxies over a volume of the Universe.

Because light takes so long to reach Earth, it was the equivalent of looking seven billion years back in time – more than half way back to the Big Bang.

The survey, which took four years to complete, aimed to measure the properties of "dark energy" – the concept of which was revived in the late 1990s when astronomers began to realise the Universe was expanding at an accelerating rate.

"The acceleration was a shocking discovery, because it showed we have a lot more to learn about physics.

Astronomers began to think that Einstein's blunder wasn't a blunder at all and that the Universe really was filled with a new kind of energy that was causing it to expand at an increasing speed," Dr Blake said.

WiggleZ used two other kinds of observations to provide an independent check on the supernovae results. One measured the pattern of how galaxies are distributed in space and the other measured how quickly clusters of galaxies formed over time.

"WiggleZ says dark energy is real. Einstein remains untoppled," he said.

According to team member Warrick Couch, confirming the existence of the anti-gravity agent is a significant step forward in understanding the Universe.

"Although the exact physics required to explain, dark energy still remains a mystery, knowing that dark energy exists has advanced astronomers' understanding of the origin, evolution and fate of the Universe," he said.

The findings are to be published in Monthly Notices of the Royal Astronomical Society journal.