Drawing of the path of near-Earth asteroid 2012ge DA14 when it passes close to Earth on Feb. 15, 2013. (NASA)

Earth is about to have a close encounter with an asteroid, the nearest an object of its size has ever come to our planet.

The fly-by is expected to occur at around 1924 UTC on Feb. 15, according to scientists at NASA’s Jet Propulsion Laboratory.

The US space agency says there’s no chance the asteroid will collide with Earth.

“This is a record-setting close approach,” says Don Yeomans of NASA’s Near Earth Object Program at JPL. “Since regular sky surveys began in the 1990s, we’ve never seen an object this big get so close to Earth.”

Scientists expect the asteroid to pass us at a distance of about 27,700 km from the surface of the Earth. That’s close enough for it to pass inside the ring of a number of geosynchronous weather and communications satellites currently orbiting the Earth at about 36,000 km from Earth’s surface above the equator.

However, the asteroid should fly well above most of the satellites and spacecraft circling the planet, including the International Space Station (ISS).

To get an idea of just how close the 2012 DA14 asteroid will get to us, consider that it will come nearer to us than the moon, about 1/13th of the distance to the Moon, which is 384,400 km from Earth.

It’s expected to whiz by our planet quite fast, at a speed of about 7.8 kilometers per second in a south-to-north direction. This will be the closest an asteroid has come to Earth in at least 30 years and will give researchers a unique opportunity  to study it.

The 2012 DA14 is quite small, weighing about 130,000 metric tons and measuring about 45 meters across, less than the width of a soccer field. Astronomers believe it is made of stone, rather than metal or ice.

The asteroid was discovered by astronomers at the OAM Observatory in La Sagra, Spain less than a year ago, on Feb. 23, 2012, which is why “2012″ is part of its name.

NASA video feature of asteroid fly-by

A few other asteroids have flown even closer to Earth, but they were much smaller than the one expected to zoom by this month.  Scientists say objects of this size fly this close to the Earth about once every 40 years; an actual collision with Earth happens about every 1,200 years.

The 2012 DA14 asteroid is so tiny, it’s expected to look like a small point of light, even to those using the biggest optical telescopes. Difficult to see with the naked eye, it will be easily visible with a good set of binoculars or a small telescope.

Astronomers say the best place to see the asteroid will be in Indonesia, but people in Eastern Europe, Asia and Australia should also be able to get a glimpse.

The public can watch the event through live feeds from telescopes in La Sagra and Tenerife, Spain.

NASA astronomers at the Goldstone Deep Space Communications Complex (GDSCC) in California’s Mojave Desert will use radar imaging to determine the orbit of the asteroid, allowing them to better predict future encounters. The imaging data will also be used to create a 3D map showing the asteroid from all sides and should reveal more about the asteroid’s physical characteristics, such as its size and spin.

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.

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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