After a two-year study led by Tommaso Giannantonio and Robert Crittenden, the scientists conclude that the likelihood of its existence stands at 99.996 per cent. Their findings are published in the journal Monthly Notices of the Royal Astronomical Society.
Professor Bob Nichol, a member of the Portsmouth team, said: "Dark energy is one of the great scientific mysteries of our time, so it isn't surprising that so many researchers question its existence.
"But with our new work we're more confident than ever that this exotic component of the Universe is real – even if we still have no idea what it consists of."
Over a decade ago, astronomers observing the brightness of distant supernovae realised that the expansion of the Universe appeared to be accelerating. The acceleration is attributed to the repulsive force associated with dark energy now thought to make up 73 per cent of the content of the cosmos. The researchers who made this discovery received the Nobel Prize for Physics in 2011, but the existence of dark energy remains a topic of hot debate.
Many other techniques have been used to confirm the reality of dark energy but they are either indirect probes of the accelerating Universe or susceptible to their own uncertainties. Clear evidence for dark energy comes from the Integrated Sachs Wolfe effect named after Rainer Sachs and Arthur Wolfe.
The significance of the integrated Sachs-Wolfe effect revisited - Tommaso Giannantonio, Robert Crittenden, Robert Nichol, Ashley J. Ross
- arXiv.org > astro-ph > arXiv:1209.2125 > 10 Sep 2012