Flat Earth, old myth. Flat Universe, new physics

Jason Palmer - Researchers have developed a simple technique that adds evidence to the theory that the Universe is flat.

Moreover, the method - developed by revisiting a 30-year-old idea - confirms that "dark energy" makes up nearly three-quarters of the Universe.

The research, published in Nature, uses existing data and relies on fewer assumptions than current approaches.

Author Christian Marinoni says the idea turns estimating the Universe's shape into "primary school" geometry.

While the idea of the Earth being flat preoccupied the first philosophers millennia ago, the question of whether the Universe itself is flat remains a debatable topic.

The degree to which the Universe is curved has an effect on what astronomers see when they look into the cosmos.

A telescope on or near Earth may see an image of a celestial object differently from how the object actually looks, because the very fabric of space and time bends the light coming from it.

Christian Marinoni and Adeline Buzzi of the University of Provence have made use of this phenomenon in their technique.

Dark prospect

The current model of cosmology holds that only 4% of what makes up our Universe is normal matter - the stuff of stars and planets with which we are familiar, and that astronomers can see directly. ...

The overwhelming majority of the Universe, the theory holds, is composed of dark matter and dark energy. They are "dark" because they evidently do not absorb, emit and reflect light like normal matter, making direct views impossible.

Dark energy - purported to make up 73% of the known Universe - was proposed as the source of the ongoing expansion of everything in the cosmos. Astronomers have also observed that this expansion of the Universe seems to be accelerating.

Even though gravity holds that everything should attract everything else, in every direction astronomers look there is evidence that things are in fact moving apart - with those objects further away moving faster. ...

"In general relativity, there is a direct connection between geometry and dynamics," Professor Marinoni explained, "so that once you measure the abundance of matter and energy in the Universe, you have direct information on its geometry; you can do geometry as we learn in primary school."

The team's conclusions suggest the Universe is indeed flat - an assumption first put forth by Albert Einstein and seemingly confirmed by more recent observations but that remains one of the most difficult ideas to put on solid theoretical footing.

Alan Heavens, a theoretical astrophysicist at the University of Edinburgh, said that the strength of the result lies in that it requires few assumptions about the nature of the cosmos. ...

via BBC News - Dark energy and flat Universe exposed by simple method.