Artist’s impression of a very distant quasar powered by a black hole with a mass two billion times that of the Sun. (Image: ESO/M. Kornmesser via Wikimedia Commons)

Scientists have found the largest known structure in the universe, a cluster of galactic cores so vast it would take four billion years for a spacecraft traveling at the speed of light to cross it.

The sighting challenges a theory from Einstein which suggests such a massive object shouldn’t exist in the universe.

A quasar is the compacted center of a galaxy surrounding a massive black hole from the early days of the universe.  Quasars  go through periods of extreme brightness which can last anywhere from 10 to 100 million years. They tend to band together in enormous clusters, or structures, forming large quasar groups (LQGs).

The international group of scientists led by Roger Clowes from the University of Central Lancashire’s Jeremiah Horrocks Institute, used data from the Sloan Digital Sky Survey (SDSS), a major surveying project that uses 2.5-m wide-angle optical telescope located at New Mexico’s Apache Point Observatory, to make their findings.

Clowes and his colleagues are astounded by the size of this structure, which defies the Cosmological Principal, based on Albert Einstein’s theory of General Relativity that assumes when you look at the universe from a sufficiently large scale; it looks the same no matter where you are observing it from.  The Cosmological Principle, according to the research team, is assumed but has never been demonstrated observationally ‘beyond reasonable doubt.’

Large quasar group (LQG) as imaged by the Big Throughput Camera at the Cerro Tololo Inter-American Observatory in Chile (Photo: Chris Haines)

“While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe,” said Clowes. “This is hugely exciting, not least because it runs counter to our current understanding of the universe. The universe doesn’t seem to be as uniform as we thought.”

Clusters of galaxies can be anywhere from six to 10 million light-years across, but the LQGs can be 650 million light-years or more across. Making calculations based on the Cosmological Principle, along with the modern theory of cosmology, astrophysicists shouldn’t be able to find a structure in the universe larger than 1.2 billion light-years, much less four billion light-years across as this newly sighted structure is.

To get some additional perspective of what the astronomers found, let’s step back and give it a sense of scale.  Our own galaxy, the Milky Way, is separated from its nearest neighbor, the Andromeda Galaxy, by a distance of 2.5 million light-years.

Clowes points out that his team’s discovery does have a typical dimension of 1.6 billion light-years. But, because it is elongated, its longest dimension is four billion light-years, making it about 1,650 times larger than the distance from the Milky Way to Andromeda.

This small portion of a deep space image taken by the Canada-France-Hawaii Telscope Legacy Survey reveals thousands of galaxies yet to be explored. (Image: © CFHT/Coelum/Terapix/AstrOmatic)

Scientists have released the final version of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS), data gathered over six years which probes deep recesses of the Universe, including galaxies as far as nine billion light-years away.

This treasure trove of information  will allow scientists to better study dark matter; energy;  new, developing and evolving galaxies; and any solar system bodies beyond the orbit of Neptune, in a region called the Kuiper Belt.

The unique and powerful multi-color collection of astronomical images and data put together by the international team,  was gathered from the Canada-France-Hawaii Telescope (CFHT) located atop the summit of Hawaii’s Mauna Kea volcano.

The project is led by French and Canadian astronomers who imaged and mapped an extremely large volume of the Universe using a ground-based, rather than space telescope, such as the Hubble.

The dome of the Canada-France-Hawaii Telescope (CFHT) is a world class 3.6-meter telescope that sits above the clouds atop Hawaii’s Mauna Kea, a dormant volcano. (Photo: © J.-C. Cuillandre (CFHT))

“The Legacy Survey has already generated a lot of results and is the most heavily cited work from CFHT,” says Raymond Carlberg of the University of Toronto, who helped with project planning and oversight.

The high-quality images  allowed them to produce a large data bank which includes dark matter maps on the largest scale  ever  observed, according to the researchers.

The data set also contains the first high-quality light measurements which show that dark energy closely resembles the cosmological constant,  which counteracts the gravitational pull of matter, something  Albert Einstein predicted in his General Theory of Relativity and  later thought might have been his greatest mistake.

Although dark matter and dark energy dominate the universe,  they can’t be seen or identified.  However, astronomers are able to measure the effect that dark energy has on the rate of the expansion of our universe.

To help scientists gain a better understanding of dark energy, the Legacy Survey team set out to precisely measure several hundred “Type Ia” supernovae, which they say are excellent standard light measurements for measuring galaxy distances.

At the heart of the Legacy Survey was a state-of-the-art, 340-Megapixel digital camera called MegaCam, that was coupled to the 3.6-meter Canada-France-Hawaii telescope in Hawaii.  More than 15,000 individual MegaCam images were used to produce the survey.

This is image filled with a number of galaxies and other cosmological objects was taken from just a very small fraction of the Canada-France-Hawaii Telescope Legacy Survey (Image: ©CFHT/Coelum)

Observations began in 2003 and ended in 2009.  The scientists then took three more years to precisely calibrate the huge volume of data gathered from the images.

In the course of their work, project members were able to image and map across a combined area of the heavens which is about 800 times the surface area of the full moon as seen in the sky.

The survey revealed some 38 million celestial objects, which were mostly  distant galaxies in various stages of evolution.

The search for new solar system bodies beyond Neptune’s orbit, in a region called the Kuiper Belt, also proved successful. That area of space contains numerous chunks of material left over from when the solar system formed.

The astronomers  were able to collect what they term “an exceptional sample” of minor bodies in that region.

A new initiative, the Canada-France Ecliptic Plane Survey, has taken over that area of study. With Legacy Survey data, as well from other telescopes, those scientists have so far been able to determine the orbits of nearly 200 Kuiper Belt objects with high-precision. Other astronomers studying the formation of our solar system are also using the Legacy Survey’s information to test various scientific models.

“The legacy  will not be limited to follow-ups of the survey,” says Yannick Mellier, who leads a group of scientists  contributing to the European Space Agency’s Euclid mission – a space telescope with cameras designed to accurately measure dark energy. “MegaCam and the CFHTLS truly paved the way for the Euclid space mission both from the scientific and technical aspects.”

As shown in the above video, the supernova reaches its peak very quickly (a few days) and then slowly fades out over weeks to months. At its peak, a supernova can shine brighter than all the other stars combined in the host galaxy. The animation spans about 4 months, from pre- to post-supernova status. Credit: SNLS

Taken from stills of a simulation of the universe’s evolution, this is a visualization of large-scale structures in the universe over time. (Photo: Habib et al./Argonne National Lab)

Since they can’t turn back time to witness the creation of the universe almost 14 billion years ago, scientists are working on the next best thing: creating a virtual universe, starting at the beginning with the Big Bang.

With the help of the world’s third^-fastest computer, physicists from the US Department of Energy’s Argonne National Laboratory are developing  simulations that will take them on a trip from the origins of the universe until today.

This is a mosaic of the images covering the entire sky as observed by the Wide-field Infrared Survey Explorer (WISE).  Sky surveys such as this will be used to create simulations of the universe. (Image: NASA/JPL-Caltech/UCLA)

Over the years, scientists have scanned the night skies with telescopes which produced maps of the universe.  With the advances in astronomical technology, more details about the cosmos have emerged from these surveys.

Taking data from the best sky surveys and running it through Argonne’s Mira Supercomputer, the team plans to produce some of the largest high-resolution simulations of the distribution of matter in the universe.

Given the improvements in technology, Salman Habib, one of the project leaders, says it makes sense to try to understand  the universe  on the biggest possible scale.

“In effect, all of science, as you know it, can be studied by looking at the evolution of the universe,” says Habib.

The planned simulation, according to Katrin Heitmann, a co-leader on the project, will include  images and movies of the universe at different times.  Scientists who use the team’s recreation of the universe for their own cosmological research will be able to gather information taken and measured from the statistics produced by the simulation.

Scientists hope the project will help shed greater light on Dark Matter, a theoretical form of matter scientists believe accounts for much of the total mass in the universe.

Habib points out that we’re used to thinking of space as something static or fixed, but as time progresses new space continues to be created. The expansion of the universe is predicted by Einstein’s general theory of relativity, but that same theory, according to Habib, also states that that expansion should slow down with time.

Albert Einstein (circa 1921) theorized  the expansion of the universe slows over time.  However, recent observations suggest the opposite might be true and that the universe is continuing to expand.  (Photo: Creative Commons/Wikipedia)

However, observations made over recent years, including work by winners of the Nobel Prize in Physics in 2011,  show the opposite is true, that in fact, the universe is expanding at an accelerated rate.

The cause of this expansion remains a mystery, according to Habib, but a number of scientists think  Dark Energy is the force behind the universe’s rapid growth.

The team also hopes to learn more about Dark Energy, the hypothetical form of energy thought to compose about 70 percent of the universe .

According to Habib, scientists are unsure exactly what Dark Energy is.

To help solve this mystery,  different models of what Dark Energy could be will be put through the simulation to allow scientists to compare the observational results of each model.

Habib and his colleagues hope their simulations will not only help scientists check various models of Dark Energy, and the properties of Dark Matter, but will also provide a kind of grand picture of the evolution of the universe.

Project leaders Habib and Heitmann join us this weekend on the radio edition of Science World to talk about creating a virtual universe.

Check out the right column for scheduled air-times or listen now to the interview below.

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