Earth not center of the universe, surrounded by 'dark energy': UBC cosmologists

December 19, 2008

Earth's location in the Universe is utterly unremarkable, despite recent theories that propose toppling a foundation of modern cosmology, according to a team of University of British Columbia researchers.

Polish astronomer Nicolaus Copernicus's 1543 book, On the Revolutions of the Heavenly Spheres, moved Earth from being the centre of the Universe to just another planet orbiting the Sun. Since then, astronomers have extended the idea and formed the Copernican Principle, which says that our place in the Universe as a whole is completely ordinary. Although the Copernican Principle has become a pillar of modern cosmology, finding conclusive evidence that our neighbourhood of the Universe really isn't special has proven difficult.

In 1998, studies of distant explosions called "type Ia supernovae" indicated that the expansion of the Universe is accelerating, an observation attributed to the repulsive force of a mysterious "dark energy." However, some scientists put forward an alternate theory: They proposed that the Earth was near the centre of a giant "bubble," or "void," mostly empty of matter, and strongly violating the Copernican Principle. If this were the case, gravity would create the illusion of acceleration, mimicking the effect of dark energy on the supernova observations.

Now some advanced analysis and modeling performed by UBC post-doctoral fellows Jim Zibin and Adam Moss and Astronomy Prof. Douglas Scott is showing that this alternate "void theory" just doesn't add up. Their findings are published today in the journal Physical Review Letters.

The researchers used data from the Wilkinson Microwave Anisotropy Probe satellite, which includes members from UBC on its international team, as well as data from various ground-based instruments and surveys.

"We tested void models against the latest data, including subtle features in the cosmic microwave background radiation - the afterglow of the Big Bang - and ripples in the large-scale distribution of matter," says Zibin. "We found that void models do a very poor job of explaining the combination of these data."

The team's calculations instead solidify the conventional view that an enigmatic dark energy fills the cosmos and is responsible for the acceleration of the Universe. "Recent advances in data collection have brought us to the era of precision cosmology," says Zibin. "Void models are terrible at explaining the new data, but the standard dark energy model works very well.

"Since we can only observe the Universe from Earth, it's really hard to determine if we're in a 'special place,'" says Zibin. "But we've now learned that our location is much more ordinary than the strange dark energy that fills the Universe."
-end-
The journal paper is available online at http://link.aps.org/abstract/PRL/v101/e251303

University of British Columbia

Related Dark Energy Articles from Brightsurf:

UH Mānoa researchers predict location of novel candidate for mysterious dark energy
UH researchers explain what may be the cause of the universe's accelerating growth.

New test of dark energy and expansion from cosmic structures
A new paper has shown how large structures in the distribution of galaxies in the Universe provide the most precise tests of dark energy and cosmic expansion yet.

IKBFU astrophysicists have developed a theory explaining the 'Dark Energy' phenomenon
The article refers to the issue of the 'Dark Enegry' and an assumption is made that the Universe has borders.

Are black holes made of dark energy?
Two University of Hawaii at Manoa researchers have identified and corrected a subtle error that was made when applying Einstein's equations to model the growth of the universe.

Lab-based dark energy experiment narrows search options for elusive force
An experiment to test a popular theory of dark energy has found no evidence of new forces, placing strong constraints on related theories.

A survey machine and a data trove: Dark Energy Survey's rich legacy
On the night of Jan. 9, 2019, the V. M.

String theory: Is dark energy even allowed?
In string theory, a paradigm shift could be imminent. In June, a team of string theorists from Harvard and Caltech published a conjecture which sounded revolutionary: String theory is said to be fundamentally incompatible with our current understanding of 'dark energy'.

Dark energy survey publicly releases first three years of data
At a special session held during the American Astronomical Society meeting in Washington, D.C., scientists on the Dark Energy Survey (DES) announced today the public release of their first three years of data.

Star mergers: A new test of gravity, dark energy theories
Observations and measurements of a neutron star merger have largely ruled out some theories relating to gravity and dark energy, and challenged a large class of theories.

Doing without dark energy
Three mathematicians have a different explanation for the accelerating expansion of the universe that does without theories of 'dark energy.' Einstein's original equations for General Relativity actually predict cosmic acceleration due to an 'instability,' they argue in paper published recently in Proceedings of the Royal Society A.

Read More: Dark Energy News and Dark Energy Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.