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Telescope takes universe’s temperature

Australia Telescope Compact Array

CSIRO’s Australia Telescope Compact Array, used the make the temperature measurements.

ASTRONOMERS USING a CSIRO radio telescope have taken the universe’s temperature, and have found that it has cooled down just the way the Big Bang theory predicts.

Using the Australia Telescope Compact Array near Narrabri, NSW, an international team from Sweden, France, Germany and Australia has measured how warm the universe was when it was half its current age.

“This is the most precise measurement ever made of how the universe has cooled down during its 13.77 billion year history,” said Dr Robert Braun, Chief Scientist at CSIRO Astronomy and Space Science.

Because light takes time to travel, when we look out into space we see the universe as it was in the past – as it was when light left the galaxies we are looking at. So to look back halfway into the universe’s history, we need to look halfway across the universe.

Cosmic fingerprint

How can we measure a temperature at such a great distance?

Illustration of radio waves coming from a distant quasar through a galaxy in the foreground and then on to Earth.

Radio waves from a distant quasar pass through another galaxy on their way to Earth. Changes in the radio waves indicate the temperature of the gas in that galaxy.

The astronomers studied gas in an unnamed galaxy 7.2 billion light-years away (at a redshift of 0.89).

The only thing keeping this gas warm is the cosmic background radiation – the glow left over from the Big Bang.

By chance, there is another powerful galaxy, a quasar (called PKS 1830-211), lying behind the unnamed galaxy.

Radio waves from this quasar come through the gas of the foreground galaxy. As they do so, the gas molecules absorb some of the energy of the radio waves. This leaves a distinctive ‘fingerprint’ on the radio waves.

From this ‘fingerprint’ the astronomers calculated the gas’s temperature. They found it to be 5.08 Kelvin (-267.92 degrees Celsius): extremely cold, but still warmer than today’s universe, which is at 2.73 Kelvin (-270.27 degrees Celsius).

Exactly as predicted

According to the Big Bang theory, the temperature of the cosmic background radiation drops smoothly as the universe expands.

“That’s just what we see in our measurements,” said research team leader Dr. Sebastien Muller of Onsala Space Observatory at Chalmers University of Technology in Sweden. “The universe of a few billion years ago was a few degrees warmer than it is now, exactly as the Big Bang theory predicts.”

Adapted from information issued by CSIRO. Images David Smyth and Onsala Space Observatory.

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Galaxy at the dawn of time

Galaxy GN-108036

One of the most distant galaxies known, called GN-108036, is seen 750 million years after the Big Bang. The galaxy's light took 12.9 billion years to reach us. Infrared observations taken by NASA's Spitzer and Hubble space telescopes show it to be surprisingly bright, thought to result from an extreme burst of star formation

  • Galaxy seen as it was 750 million years after the Big Bang
  • Observations suggest it is forming stars at a furious rate

ASTRONOMERS USING NASA’S Spitzer and Hubble space telescopes have discovered that one of the most distant galaxies known is churning out stars at a shockingly high rate. The blob-shaped galaxy, called GN-108036, is the brightest galaxy found to date at such great distances.

The galaxy, which was discovered and confirmed using ground-based telescopes, is 12.9 billion light-years away.

Data from Spitzer and Hubble were used to measure the galaxy’s high star production rate, equivalent to about 100 Suns per year.

For reference, our Milky Way galaxy is about five times larger and 100 times more massive than GN-108036, but makes roughly 30 times fewer stars per year.

“The discovery is surprising because previous surveys had not found galaxies this bright so early in the history of the universe,” said Mark Dickinson of the US National Optical Astronomy Observatory in Arizona. “Perhaps those surveys were just too small to find galaxies like GN-108036.”

“It may be a special, rare object that we just happened to catch during an extreme burst of star formation.”

Seen shortly after the Big Bang

The international team of astronomers, led by Masami Ouchi of the University of Tokyo, Japan, first identified the remote galaxy after scanning a large patch of sky with the Subaru Telescope atop Mauna Kea in Hawaii.

Its great distance was then carefully confirmed with the W.M. Keck Observatory, also on Mauna Kea.

“We checked our results on three different occasions over two years, and each time confirmed the previous measurement,” said Yoshiaki Ono of the University of Tokyo, lead author of a new paper reporting the findings in the Astrophysical Journal.

Spitzer (left) and Hubble space telescopes

The Spitzer (left) and Hubble space telescopes were used to measure the galaxy's redshift, a indication of how far away it is.

GN-108036 lies near the very beginning of time itself, a mere 750 million years after our universe formed 13.7 billion years ago in an explosive “Big Bang.”

Its light has taken 12.9 billion years to reach us, so we are seeing it as it existed in the very distant past.

Remarkable redshift

Astronomers refer to an object’s distance by a number called its “redshift,” which is a measure of how much its light has been stretched to longer, redder wavelengths due to the expansion of the universe.

Objects with larger redshifts are farther away and are seen further back in time.

GN-108036 has a redshift of 7.2. Only a handful of galaxies have confirmed redshifts greater than 7, and only two of these have been reported to be more distant than GN-108036.

Infrared observations from Spitzer and Hubble were crucial for measuring the galaxy’s star-formation activity. Astronomers were surprised to see such a large burst of star formation because the galaxy is so small and from such an early cosmic era.

Back when galaxies were first forming, in the first few hundreds of millions of years after the Big Bang, they were much smaller than they are today, having yet to bulk up in mass.

During this epoch, as the universe expanded and cooled after its explosive start, hydrogen atoms permeating the cosmos formed a thick fog that was opaque to ultraviolet light. This period, before the first stars and galaxies had formed and illuminated the universe, is referred to as the “dark ages.”

The era came to an end when light from the earliest galaxies burned through, or “ionised,” the opaque gas, causing it to become transparent. Galaxies similar to GN-108036 may have played an important role in this event.

Adapted from information issued by NASA / JPL-Caltech / STScI / University of Tokyo.

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Beyond Einstein — the video

ALBERT EINSTEIN’S THEORIES rank among humanity’s greatest achievements, and sparked the scientific revolution of the 20th Century.

In their attempts to understand how space, time and matter are connected, Einstein and his successors made three predictions:

First, that space is expanding from a Big Bang.

Second, that black holes exist—these extremely dense places in the universe where space and time are tied into contorted knots and where time itself stops.

And third, that there is some kind of energy pulling the universe apart.

These three predictions seemed so far-fetched, that everyone, including Einstein himself, thought they were unlikely.

Yet incredibly, all three have turned out to be true.

This is where NASA’s Beyond Einstein programme begins. Using advanced space-based technology to explore these three questions, NASA and its partners begin the next revolution in our understanding of the universe.

NASA’s Beyond Einstein programme is poised to complete Einstein’s legacy—and ultimately unravel the mysteries of the Universe.

Adapted from information issued by NASA / Goddard Space Flight Centre.

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Was the universe born spinning?

Galaxy Messier 101

Researchers have found an excess of counter-clockwise rotating, or 'left-handed,' spiral galaxies like the one pictured (known as Messier 101) compared to their 'right-handed' counterparts. This provides evidence that the universe does not have mirror symmetry, and that it may have been born spinning at the time of the Big Bang.

  • Universe long thought to have ‘mirror symmetry’
  • Symmetry could be wrong if more galaxies spin in one direction
  • Early results show more galaxies rotate ‘left’ than ‘right’

PHYSICISTS AND ASTRONOMERS have long thought that the universe has mirror symmetry, like a basketball, but recent findings from the University of Michigan dispute this.

The findings suggest that the shape of the Big Bang might be more complicated than previously thought, and that the early universe spun about an axis.

To test for the assumed mirror symmetry, physics professor Michael Longo and a team of five undergraduates catalogued the rotation direction of tens of thousands of spiral galaxies photographed in the Sloan Digital Sky Survey.

The mirror image of a counter-clockwise rotating galaxy would have clockwise rotation. More of one type than the other would be evidence for a breakdown of symmetry, or, in physics speak, a ‘parity violation’ on cosmic scales, Longo said.

One in a million

The researchers found evidence that galaxies tend to rotate in a preferred direction.

They uncovered an excess of left-handed, or counter-clockwise rotating, spirals in the part of the sky toward the north pole of the Milky Way. The effect extended beyond 600 million light-years away.

“The excess is small, about 7 percent, but the chance that it could be a cosmic accident is something like one in a million,” Longo said.

Spiral galaxy NGC 4622

Spiral galaxy NGC 4622

“These results are extremely important because they appear to contradict the almost universally accepted notion that on sufficiently large scales the universe is isotropic, with no special direction.”

Spin cycle

The work provides new insights about the shape of the Big Bang. A symmetric and isotropic universe would have begun with a spherically symmetric explosion shaped like a basketball.

If the universe was born rotating, like a spinning basketball, Longo said, it would have a preferred axis, and galaxies would have retained that initial motion.

Is the universe still spinning?

“It could be,” Longo said. “I think this result suggests that it is.”

Because the Sloan telescope is in New Mexico, the data the researchers analysed for their recent paper came mostly from the northern regions of the sky. An important test of the findings will be to see if there is an excess of right-handed spiral galaxies in the southern hemisphere. This research is currently under way.

Adapted from information issued by the University of Michigan. Messier 101 image courtesy NASA, ESA, K. Kuntz (Johns Hopkins University), F. Bresolin (University of Hawaii), J. Trauger (Jet Propulsion Lab), J. Mould (National Optical Astronomy Observatory), Y.-H. Chu (University of Illinois, Urbana), and the Space Telescope Science Institute. NGC 4622 image courtesy NASA and The Hubble Heritage Team (STScI/AURA); acknowledgment: Dr. Ron Buta (U. Alabama), Dr. Gene Byrd (U. Alabama) and Tarsh Freeman (Bevill State Community College).

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Most distant quasar found

Artist’s impression of quasar ULAS J1120+0641

This artist’s impression shows how ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun, may have looked. This quasar is the most distant yet found and is seen as it was just 770 million years after the Big Bang.

ASTRONOMERS HAVE DISCOVERED the most distant quasar to date—a development that could help further our understanding of the universe when it was still in its infancy following the Big Bang.

Quasars are distant galaxies that have very bright cores, believed to be powered by supermassive black holes at their centres. Their brilliance makes them powerful beacons that may help to probe the era when the first stars and galaxies were forming.

“It is a very rare object that will help us to understand how supermassive black holes grew a few hundred million years after the Big Bang,” says Stephen Warren, the study’s team leader.

The quasar, named ULAS J1120+0641, is seen as it was only 770 million years after the Big Bang, giving it a redshift of 7.1. The light we see coming from it took 12.9 billion years to reach us.

Striking gold

Although more distant objects have been confirmed—such as a gamma-ray burst at redshift 8.2 and a galaxy at 8.6—the newly discovered quasar is hundreds of times brighter than these. In fact, amongst objects bright enough to be studied in detail, this is the most distant by a large margin.

Objects so away cannot be found in visible-light surveys because their light, stretched by the expansion of the Universe, falls mostly in the infrared part of the spectrum by the time it gets to Earth.

The European UKIRT Infrared Deep Sky Survey (UKIDSS) which uses the UK’s dedicated infrared telescope in Hawaii was designed to solve this problem. The team of astronomers hunted through millions of objects in the UKIDSS database to find those that could be the long-sought distant quasars, and eventually struck gold.

“It took us five years to find this object,” explains Bram Venemans, one of the authors of the study. “We were looking for a quasar with redshift higher than 6.5. Finding one that is this far away, at a redshift higher than 7, was an exciting surprise.”

A rare find

Because the object is comparatively bright it is possible to take a spectrum of it (which involves splitting the light from the object into its component colours). This technique enabled the astronomers to find out quite a lot about it.

These observations show that the mass of the black hole at the centre of ULAS J1120+0641 is about two billion times that of the Sun. This very high mass is hard to explain so early on after the Big Bang, as current theories for the growth of supermassive black holes predict a slow build-up in mass as the object pulls in matter from its surroundings.

“We think there are only about 100 bright quasars with redshift higher than 7 over the whole sky,” concludes Daniel Mortlock, the leading author of the paper. “Finding this object required a painstaking search, but it was worth the effort to be able to unravel some of the mysteries of the early Universe.”

Adapted from information issued by ESO / University of Nottingham / M. Kornmesser.

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It’s official – dark energy is real!

Visualisation of dark energy

Cosmic wrestling match. In this artist's visualisation, dark energy is represented in purple and gravity in green. Dark energy is a uniform force that now dominates over the effects of gravity in the cosmos. Courtesy NASA / JPL-Caltech.

A SURVEY OF MORE THAN 200,000 GALAXIES led by Australian astronomers has shown that ‘dark energy’ is real and not a mistake in Einstein’s theory of gravity.

The finding is conveyed in two papers led by Dr Chris Blake from Swinburne University’s Centre for Astrophysics and Supercomputing, which will be published in the Monthly Notices of the Royal Astronomical Society.

Using the Anglo-Australian Telescope, 26 astronomers contributed to the ‘WiggleZ Dark Energy Survey’ that mapped the distribution of galaxies over an unprecedented volume of the Universe.

Because light takes so long to reach Earth, it was the equivalent of looking seven billion years back in time—more than half way back to the Big Bang.

The survey, which took four years to complete, aimed to measure the properties of ‘dark energy’ a concept first cast by Einstein in his original Theory of General Relativity. The scientist included the idea in his original equations, but later changed his mind, calling the inclusion “his greatest blunder”.

However, in the late 1990s when astronomers began to realise that the Universe was expanding at an accelerating rate, the concept of ‘dark energy’ was revived. This was done by measuring the brightness of distant supernovae—exploding stars.

Diagram illustrating cosmic standard candles and standard rulers

This diagram illustrates two methods that astronomers use to measure how fast the universe is expanding—the "standard candle" method, which involves studying exploded stars in galaxies, and the "standard ruler" method, which involves studying the distances between pairs of galaxies. Courtesy NASA / JPL-Caltech.

“The acceleration was a shocking discovery, because it showed we have a lot more to learn about physics,” Dr Blake said. “Astronomers began to think that Einstein’s blunder wasn’t a blunder at all, and that the Universe really was filled with a new kind of energy that was causing it to expand at an increasing speed.”

Einstein vindicated

The WiggleZ (pronounces ‘wiggles’) project has now used two other kinds of observations to provide an independent check on the supernovae results. One measured the pattern of how galaxies are distributed in space and the other measured how quickly clusters of galaxies formed over time.

Both tests have confirmed the reality of dark energy.

“WiggleZ says dark energy is real,” said Dr Blake. “Einstein remains untoppled.”

According to Professor Warrick Couch, Director of Swinburne’s Centre for Astrophysics and Supercomputing, confirming the existence of the anti-gravity agent is a significant step forward in understanding the Universe.

“Although the exact physics required to explain dark energy still remains a mystery, knowing that dark energy exists has advanced astronomers’ understanding of the origin, evolution and fate of the Universe,” he said.

According to one of the survey’s leaders, Professor Michael Drinkwater from the University of Queensland, the researchers have broken new ground. “This is the first individual galaxy survey to span such a long stretch of cosmic time,” he said.

The WiggleZ observations were possible due to a powerful spectrograph attached to the Anglo-Australian Telescope. The spectrograph was able to make measurements at the super-efficient rate of 392 galaxies an hour, despite the galaxies being located halfway to the edge of the observable Universe.

“WiggleZ has been a success because we have an instrument attached to the telescope, a spectrograph, that is one of the best in the world for large galaxy surveys of this kind,” said Professor Matthew Colless, director of the Australian Astronomical Observatory.

The WiggleZ survey involved 18 Australian astronomers, including 10 from Swinburne University of Technology. It was led by Dr Chris Blake, Professor Warrick Couch and Professor Karl Glazebrook from Swinburne and Professor Michael Drinkwater from the University of Queensland.

Adapted from information issued by AAO / Swinburne University of Technology.

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Did the early cosmos have one dimension?

Artist's impression of gravitational waves

A controversial theory suggests there was only one dimension right after the Big Bang. Extra dimensions formed as time progressed, leading to our present three-dimensional universe.

DID THE EARLY UNIVERSE have just one spatial dimension? That’s the mind-boggling concept at the heart of a theory that University at Buffalo physicist Dejan Stojkovic and colleagues proposed in 2010.

They suggested that the early universe—which exploded from a single point and was very, very small at first—was one-dimensional (like a straight line) before expanding to include two dimensions (like a plane) and then three (like the world in which we live today).

The concept, if valid, would address important problems in particle physics.

Now, in a new paper in Physical Review Letters, Stojkovic and Loyola Marymount University physicist Jonas Mureika describe a test that could prove or disprove the “vanishing dimensions” hypothesis.

Because it takes time for light and other waves to travel to Earth, telescopes peering out into space can, essentially, look back in time as they probe the universe’s outer reaches.

Gravitational waves can’t exist in one- or two-dimensional space. So Stojkovic and Mureika have reasoned that the Laser Interferometer Space Antenna (LISA), a planned international gravitational observatory, should not detect any gravitational waves emanating from the lower-dimensional, early years of the early universe.

Artist's impression of LISA

Artist's impression of the planned Laser Interferometer Space Antenna, which could will search for gravitational waves.

Quantum mechanics vs general relativity

Stojkovic, an assistant professor of physics, says the theory of evolving dimensions represents a radical shift from the way we think about the cosmos—about how our universe came to be.

The core idea is that the dimensionality of space depends on the size of the space we’re observing, with smaller spaces associated with fewer dimensions. That means that a fourth dimension will open up—if it hasn’t already—as the universe continues to expand.

The theory also suggests that space has fewer dimensions at very high energies of the kind that would have been around in the early, post-big bang universe.

If Stojkovic and his colleagues are right, they’ll be helping to address fundamental problems with the standard model of particle physics.

One of those problems is the incompatibility between quantum mechanics and general relativity.

Quantum mechanics and general relativity are mathematical frameworks that describe the physics of the universe. Quantum mechanics is good at describing the universe at very small scales (such as atoms), while relativity is good at describing the universe at the largest scales.

Albert Einstein

Einstein's general relativity theory and quantum mechanics are at odds with each other.

Currently, the two theories are considered incompatible. But if the universe, at its smallest levels, had fewer dimensions, mathematical discrepancies between the two frameworks would disappear.

Something radically wrong?

The second problem is the mystery of the universe’s accelerating expansion.

Physicists have observed that the expansion of the universe seems to be speeding up, and they don’t know why. The addition of new dimensions as the universe grows would explain this acceleration. (Stojkovic says a fourth dimension may have already opened at large, cosmological scales.)

Another problem is the need to alter the mass of the Higgs boson…an as yet undiscovered elementary particle predicted by the standard model of particle physics.

For equations in the standard model to accurately describe the observed physics of the real world, however, researchers must artificially adjust the mass of the Higgs boson for interactions between particles that take place at high energies. If space has fewer dimensions at high energies, the need for this kind of “tuning” disappears.

“What we’re proposing here is a shift in paradigm,” Stojkovic said. “Physicists have struggled with the same problems for 10, 20, 30 years, and straight-forward extensions of extensions of the existing ideas are unlikely to solve them.”

“We have to take into account the possibility that something is systematically wrong with our ideas,” he continued. “We need something radical and new, and this is something radical and new.”

Artist's impression of the Big Bang

Artist's impression of the Big Bang

Lower-dimensional space

Because the planned deployment of LISA is still years away, it may be a long time before Stojkovic and his colleagues are able to test their ideas this way.

However, some experimental evidence already points to the possible existence of lower-dimensional space.

Specifically, scientists have observed that the main energy flux of cosmic ray particles with the kind of high energy associated with the very early universe, are aligned along a two-dimensional plane.

If high energies do correspond with lower-dimensional space, as the ‘vanishing dimensions’ theory proposes, researchers working with the Large Hadron Collider particle accelerator in Europe should see ‘planar scattering’ at such energies.

Stojkovic says the observation of such events would be “a very exciting, independent test of our proposed ideas.”

Adapted from information issued by the University at Buffalo.

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Dark energy dilemma

PHYSICISTS CAN’T SEE IT and don’t know much about what it is, but they think dark energy makes up 70 percent of the universe. In this video, Professor Saul Perlmutter, one of the world’s leading scientists trying to understand dark energy, explains the role it plays in causing our universe to expand.

Adapted from information issued by Lawrence Berkeley National Laboratory / KQEDondemand.

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Astronomy 1 trillion years from now

Artist’s conception of the cosmic view a trillion years from now.

A trillion years from now, the sky will look very different. Will astronomers still be able to work out that the Big Bang happened?

ONE TRILLION YEARS FROM NOW, alien astronomers in our galaxy will have a difficult time figuring out how the universe began. They won’t have the evidence that we enjoy today.

Edwin Hubble made the first observations in support of the Big Bang model. He showed that galaxies are rushing away from each other due to the universe’s expansion.

More recently, astronomers discovered a pervasive afterglow from the Big Bang, known as the cosmic microwave background, left over from the universe’s white-hot beginning.

In a trillion years, when the universe is 100 times older than it is now, alien astronomers will have a very different view. The Milky Way will have merged with the Andromeda Galaxy to form the ‘Milkomeda Galaxy’. Many of its stars, including our Sun, will have burned out.

And the universe’s ever-accelerating expansion will send all other galaxies rushing beyond our “cosmic horizon,” sending them forever out of view.

The same expansion will cause the cosmic microwave background (CMB) to fade out, stretching the wavelength of CMB photons to become longer than the visible universe.

The universe will become dark and dull.

Artist's impression of a hypervelocity star.

Future astronomers will study hypervelocity stars to deduce the laws of the cosmos.

Shooting stars

Without the clues of the CMB and distant, receding galaxies, how will these far-future astronomers know the Big Bang happened?

According to Harvard theorist Avi Loeb, clever astronomers in the year 1 trillion CE could still infer the Big Bang and today’s leading cosmological theory, known as ‘lambda-cold dark matter’ or LCDM. They will have to use the most distant light source available to them—’hypervelocity’ stars flung from the centre of Milkomeda.

“We used to think that observational cosmology wouldn’t be feasible a trillion years from now,” said Loeb, who directs the Institute for Theory and Computation at the Harvard-Smithsonian Centre for Astrophysics.

“Now we know this won’t be the case. Hypervelocity stars will allow Milkomeda residents to learn about the cosmic expansion and reconstruct the past.”

About once every 100,000 years, a binary-star system wanders too close to the black hole at our galaxy’s centre and gets ripped apart. One star falls into the black hole while the other is flung outward at a speed greater than 1.5 million kilometres per hour—fast enough to be ejected from the galaxy entirely.

No need for faith

Finding these hypervelocity stars is more challenging than spotting a needle in a haystack, but future astronomers would have a good reason to hunt diligently. Once they get far enough from Milkomeda’s gravitational pull, these stars will get accelerated by the universe’s expansion.

Andromeda galaxy

Andromeda, the nearest big galaxy, will one day merge with our Milky Way.

Astronomers could measure that acceleration with technologies more advanced than we have today. This would provide a different line of evidence for an expanding universe, similar to Hubble’s discovery but more difficult due to the very small effect being measured.

By studying stars within Milkomeda, they could infer when the galaxy formed. Combining that information with the hypervelocity star measurements, they could calculate the age of the universe and key cosmological parameters like the value of the cosmological constant (the lambda in LCDM).

“Astronomers of the future won’t have to take the Big Bang on faith. With careful measurements and clever analysis, they can find the subtle evidence outlining the history of the universe,” said Loeb.

This research appears in a paper accepted for publication in the Journal of Cosmology and Astroparticle Physics.

Adapted from information issued by CfA. Artwork courtesy David A. Aguilar (CfA). Hypervelocity star artwork courtesy NASA, ESA, and A. Feild (STScI). Andromeda image courtesy Caltech.

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Black holes were early starters

Galaxy M87

The galaxy M87, about 100 times bigger than our Milky Way, is home to a giant black hole. The galaxy and its black hole could have been among the earliest to form after the Big Bang.

  • Big galaxies formed quickly after the Big Bang
  • So did black holes, and the two are probably connected
  • Giant galaxy M87 is probably one of those first galaxies

Astronomers think they have nutted out the origin of our Universe’s first super-massive black holes, which formed some 13 billion years ago.

In the journal Nature, Ohio State University astronomer Stelios Kazantzidis and colleagues describe computer simulations in which they modelled the growth of galaxies and black holes during the first few billion years after the Big Bang.

For more than 20 years, the prevailing wisdom had been that galaxies evolved slowly as gravity drew small bits of matter together first, and those small bits gradually came together to form larger structures and so on.

But recently, other astronomers determined that big galaxies formed much earlier in the Universe’s history than previously thought—within the first 1 billion years. (The Universe is thought to be 13.7 billion years old.)

Computer simulation of two galaxies merging

Computer simulation of two galaxies merging (from top left). The result is a giant galaxy with a huge black hole in its core (bottom right).

The new computer simulations show that the first super-massive black holes were likely born as a result of those big galaxies colliding and merging.

Matter is thought to be a mixture of “normal matter”—eg. stars, galaxies and black holes—and “dark matter”, some as-yet-unknown and invisible stuff that far outweighs the amount of normal matter.

Kazantzidis and his team found that while dark matter grouped together in the early Universe in a slow, step-by-step fashion, normal matter formed into “clumps” in a much faster manner. And so “…our result shows that big structures—both galaxies and massive black holes—[built] up quickly…” he said.

They also found that smaller structures like our own modest Milky Way galaxy—and the comparatively small black hole at its centre—formed more slowly.

The merged galaxies in which the first super-massive black holes formed are still around today, Kazantzidis says.

“One of them is likely our neighbour in the Virgo Cluster, the elliptical galaxy M87,” he said. “The galaxies we saw in our simulation would be the biggest galaxies known today, about 100 times the size of the Milky Way. M87 fits that description.”

Adapted from information issued by Ohio State University / CFHT.

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