The black hole at the birth of the Universe

Before the Big Bang.

Credit: Image courtesy of Perimeter Institute

The big bang poses a big question: if it was indeed the cataclysm that blasted our universe into existence 13.7 billion years ago, what sparked it?

Three Perimeter Institute researchers have a new idea about what might have come before the big bang.

It's a bit perplexing, but it is grounded in sound mathematics and is it testable?

What we perceive as the big bang, they argue, could be the three-dimensional "mirage" of a collapsing star in a universe profoundly different than our own.

"Cosmology's greatest challenge is understanding the big bang itself," write Perimeter Institute Associate Faculty member Niayesh Afshordi, Affiliate Faculty member and University of Waterloo professor Robert Mann, and PhD student Razieh Pourhasan.

Conventional understanding holds that the big bang began with a singularity, an unfathomably hot and dense phenomenon of spacetime where the standard laws of physics break down.

Singularities are bizarre, and our understanding of them is very limited.

"For all physicists know, dragons could have come flying out of the singularity," Afshordi says in an interview with Nature.

The problem, as the authors see it, is that the big bang hypothesis has our relatively comprehensible, uniform, and predictable universe arising from the physics-destroying insanity of a singularity. It seems unlikely.

So perhaps something else happened. Perhaps our universe was never singular in the first place.

Their suggestion: our known universe could be the three-dimensional "wrapping" around a four-dimensional black hole's event horizon.

In this scenario, our universe burst into being when a star in a four-dimensional universe collapsed into a black hole.

In our three-dimensional universe, black holes have two-dimensional event horizons -- that is, they are surrounded by a two-dimensional boundary that marks the "point of no return."

In the case of a four-dimensional universe, a black hole would have a three-dimensional event horizon.

In their proposed scenario, our universe was never inside the singularity; rather, it came into being outside an event horizon, protected from the singularity.

It originated as, and remains, just one feature in the imploded wreck of a four-dimensional star.

The researchers emphasize that this idea, though it may sound "absurd," is grounded firmly in the best modern mathematics describing space and time.

Specifically, they've used the tools of holography to "turn the big bang into a cosmic mirage."

Along the way, their model appears to address long-standing cosmological puzzles and, crucially -- produce testable predictions.

Of course, our intuition tends to recoil at the idea that everything and everyone we know emerged from the event horizon of a single four-dimensional black hole. We have no concept of what a four-dimensional universe might look like. We don't know how a four-dimensional "parent" universe itself came to be.

But our fallible human intuitions, the researchers argue, evolved in a three-dimensional world that may only reveal shadows of reality.

They draw a parallel to Plato's allegory of the cave, in which prisoners spend their lives seeing only the flickering shadows cast by a fire on a cavern wall.

"Their shackles have prevented them from perceiving the true world, a realm with one additional dimension," they write.

"Plato's prisoners didn't understand the powers behind the sun, just as we don't understand the four-dimensional bulk universe but at least they knew where to look for answers."

Journal Reference: Razieh Pourhasan, Niayesh Afshordi, Robert B. Mann. Out of the White Hole: A Holographic Origin for the Big Bang. arXiv, 2014

Astrophysicist suggests life existed shortly after Big Bang?

Time Line of the Universe. Credit: NASA/WMAP Science Team

Theoretical astrophysicist Abraham Loeb of Harvard University  suggests that conditions shortly after the Big Bang may have been just right for life to appear in some parts of the universe—for just a short time.

Loeb notes that according to theory, 15 million years after the Big Bang, the entire universe would have been warm enough to support life due to the cooling of superheated gases that eventually led to what scientists believe is cosmic microwave background (CMB).

Abraham Loeb

Today, it's very cold of course, (2.7 Kelvin), but not long, relatively speaking, after the Big Bang, the temperature would have been closer to 300 Kelvin—more than warm enough to support life if there were a place for it to appear.

Loeb suggests that it might have been possible as well. He notes that it would have been possible for rocky planets to have existed at that time too—in places where matter was exceptionally dense.

Because of that, he believes it's possible that all of the pieces necessary for the appearance of life might have been in place in some parts of the universe, for approximately two or three million years—enough time for the initial brewing that could have led to the development of microbes of some sort.

Of course, if it did happen, that life would not have lived long enough (2 to 3 million years) to evolve into anything complex—it would have been snuffed out as the CMB cooled—happening as it would have before stars would have had enough time to form and emit heat of their own.

Thus, no evidence would have been left behind, which means Loeb's theory can never be proven. If it could, that might upset another principle regarding the universe—the anthropic principle—which suggests that all of the things that needed to happen in the universe for us to be here today to observe them, exist because we are here to observe them.

If life existed and died out before we arrived, it would not have been sophisticated enough to know that it existed, much less observe conditions in the universe that led to its existence.

And that would mean the anthropic principle might just be an idea that exists because we have nothing better to explain how and why we are here.

More information: The Habitable Epoch of the Early Universe, arXiv:1312.0613 [astro-ph.CO] arxiv.org/abs/1312.0613

Big Bang Aftermath: From Darkness to Light

An international team of scientists has found a clue as to what happened in the universe after the Big Bang.

They claim that just after the big bang, a dense hydrogen fog that was seen across the universe was completely burned off in some isolated, low-density regions of the universe.

A few hundred million years later, reionisation took place in the dense, crowded regions of the universe.

Previously, astronomers claimed that just after big bang, a dense hydrogen "fog" settled over the universe. During this time, a lot of the light produced by the first stars could only travel short distances before it was absorbed by the fog.

They call this period the "dark ages" of the universe, but little is known about what was happening at this time.

Now scientists have found that hydrogen fog was burned off first in isolated, low-density regions of the universe. They also found that galaxies in crowded regions of the universe were more likely to be shrouded in very dense pockets of hydrogen fog.

Such dense regions would therefore require larger numbers of light sources and more time to burn off the fog compared to regions with relatively light fog.

Scientists discovered this when they studied several reionisations that took place around three galaxies, including the Milky Way.

"We used nearby galaxies to understand something that happened long ago, in much the same way fossils are used to understand earth's history," said Duncan Forbes, professor at the Swinburne University of Technology.

"We can see regions around galaxies where reionisation has just finished and use that information to understand important questions about the dark ages: What were the first stars like; how were the first galaxies formed; and were there many supermassive black holes," he added.

"Understanding how reionisation moved through the universe is very challenging but of enormous importance in astronomy.

Our technique provides a novel way to tackle this problem," said Dr Lee Spitler, astrophysicist at the Swinburne University of Technology, in a statement.

Scientists claim that further studies will help them understand more about the dark ages and the evolution of the universe.

Hubble Archive Image: Old star reveals Arsenic and Selenium

An ultraviolet spectrum taken from the Hubble Space Telescope public archives revealed arsenic and selenium in a 12 billion year-old halo star dubbed HD 160617.

"Arsenic and selenium elements were forged in an even older star, which has long since disappeared, and then-like genes passed on from parent to infant-they were born into the star we see today, HD 160617." reported Ian Roederer, along with co-author James Lawler.

The Big Bang produced lots of hydrogen and helium and a smidgen of lithium.

All heavier elements found on the periodic table have been produced by stars over the last 13.7 billion years. Astronomers analyze starlight to determine the chemical makeup of stars, the origin of the elements, the ages of stars, and the evolution of galaxies and the universe.

Now for the first time, astronomers have detected the presence of arsenic and selenium, neighbouring elements near the middle of the periodic table, in an ancient star in the faint stellar halo that surrounds the Milky Way.

Arsenic and selenium are elements at the transition from light to heavy element production, and have not been found in old stars until now.

Lead author of the Astrophysical Journal paper, Fellow Ian Roederer of the Carnegie Observatories explained: "Stars like our Sun can make elements up to oxygen on the periodic table. Other more massive stars can synthesize heavier elements, those with more protons in their nuclei, up to iron by nuclear fusion-the process in which atomic nuclei fuse and release lots of energy. Most of the elements heavier than iron are made by a process called neutron-capture nucleosynthesis."

"Although neutrons have no charge, they can decay into protons after they're in the nucleus, producing elements with larger atomic numbers. One of the ways that this method can work is by exposure to a burst of neutrons during the violent supernova death of a star."

"We call this process the rapid process (r-process). It can produce elements at the middle and bottom of the periodic table-from zinc to uranium-in the blink of an eye."

Roederer, with co-author James Lawler, looked at an ultraviolet spectrum from the Hubble Space Telescope public archives to find arsenic and selenium in a 12 billion year-old halo star dubbed HD 160617.

"These elements were forged in an even older star, which has long since disappeared, and then-like genes passed on from parent to infant-they were born into the star we see today, HD 160617."

The team also examined data for this star from the public archives of several ground-based telescopes and were able to detect 45 elements. In addition to arsenic and selenium, they found rarely seen cadmium, tellurium, and platinum, all of which were produced by the r-process.

This is the first time these elements have been detected together outside the Solar System. Astronomers cannot replicate the r-process in any laboratory since the conditions are so extreme. The key to modeling the r-process relies on astronomical observations.

"What I find exciting is that arsenic and selenium can be found in other stars, even ones like HD 160617 that we've been studying for decades," remarked Roederer.

"Now that we know where to look, we can go back and study these elements in other stars. Understanding the r-process helps us know why we find certain elements like barium on Earth, or understand why uranium is so rare."

Big Bang Expansion

Astronomers Find ‘Pristine’ Gas Formed Minutes After Big Bang

Astronomers have discovered two clouds of gas in the same state as they were in just moments after the Big Bang.

Unlike everything else in the universe, the two clouds never combined with elements that were later formed in stars.

Instead, each consists only of the light elements that occurred in the Big Bang some 14 billion years ago.

Nuclear reactions created the three lightest elements - hydrogen, helium, and a tiny amount of lithium - which stars then converted into heavier elements such as carbon and oxygen.

This new discovery is the first time astronomers have found a star or cloud made solely of these three lighter elements. All known stars and gas clouds contain at least a small amount of "metals", the term astronomers use to describe any element that is heavier than helium, including oxygen and carbon.

"As hard as we've tried to find pristine material in the universe, we have failed until now," says J Xavier Prochaska, professor of astronomy and astrophysics at the University of California, Santa Cruz.

"This is the first time we've observed pristine gas uncontaminated by heavier elements from stars."

"It's quite exciting, because it's the first evidence that fully matches the composition of the primordial gas predicted by the big bang theory," says Michele Fumagalli of the University of California, Santa Cruz, lead author of a paper on the findings published online in Science today.

"Their chemical composition is unusual," says Fumagalli. "This gas is of primordial composition, as it was produced during the first few minutes after the Big Bang."

The researchers discovered the clouds of gas using the HIRES spectrometer on the Keck I Telescope at the M Keck Observatory in Hawaii.

Previously, the lowest abundances of metals in the universe were around one-thousandth of the sun's "metallicity." At the other end of the scale, stars and gas with the highest metallicities are almost ten times that of the sun.

Visual Trip across the Universe

So what would it look like to travel across the universe then? To help us visualize this, the American Museum of Natural History (AMNH) in partnership with Rubin Museum of Art has produced a modern movie titled “The Known Universe“, directed by Carter Emmart and curated by Ben R. Oppenheimer using visualization software “Uniview by SCISS” – featuring many visual highlights of such a trip.

The video starts in Earth’s Himalayan Mountains, the Tibetan Plateau and then dramatically zooms out, showing the orbits of Earth’s satellites, the Sun, the Solar System, the extent of humanities first radio signals, the Milky Way Galaxy, galaxies nearby, distant galaxies, and quasars.

As the distant surface of the microwave background is finally reached, radiation is depicted that was emitted billions of light years away and less than one million years after the Big Bang.

Watch this awesome video clip and get ready to be stunned. (You can see it in 720p HD quality too)

ESA Herschel Images: Our Celestial Backyard

A picture of the first field observed in the H-ATLAS survey, made by combining the images made with the SPIRE camera at 250, 350 and 500 microns.

The colours in the image are not real but have been used to represent the different infrared wavelengths.

The faint blue whisps at the top of the image show dust in our own Galaxy and the bright object just above the centre of the picture is a 'Bok globule', a dense cloud of gas and dust, also in our Galaxy, in which a small star may be forming.

The other objects in the picture are all galaxies, at distances up to 12 billion light-years.

The image shows that the survey is detecting objects in our celestial ‘backyard’ and also other, further ones that we are seeing as they were not long after the Big Bang.

Credits: ESA/ATLAS Consortium

Helium clue found in echo of the big bang - space

Helium clue found in echo of the big bang - - New Scientist

THE subtle signal of ancient helium has shown up for the first time in light left over from the big bang. The discovery will help astronomers work out how much of the stuff was made during the big bang and how much was made later by stars.

Helium is the second-most abundant element in the universe after hydrogen. The light emitted by old stars and clumps of hot pristine gas from the early universe suggest helium made up some 25 per cent of the ordinary matter created during the big bang.

The new data provides another measure. A trio of telescopes has found helium's signature in the cosmic microwave background (CMB, pictured), radiation emitted some 380,000 years after the big bang. The patterns in this radiation are an important indicator of the processes at work at that time. Helium affects the pattern because it is heavier than hydrogen and so alters the way pressure waves must have travelled through the young cosmos. But helium's effect on the CMB was on a scale too small to resolve until now.

Herschel & Planck: High Risk and High Stakes

Herschel & Planck sits ready in the cargo bay of the Ariane 5 launcher.

Separately, each is a major mission. Together, they constitute a landmark in astrophysics. The probes could revolutionise our understanding of the cosmos. If everything goes to plan, Herschel and Plank will dominate space science for at least five years. But if the launch goes wrong...

With science budgets shrinking, launching two such important missions on the same rocket smacks of madness, especially given that the launcher, an Ariane 5 rocket, has suffered a couple of high-profile and expensive failures. In 1996, a computer bug caused the loss of ESA's Cluster mission, which was rebuilt at a cost of €315 million. In 2002, a commercial launch exploded, forcing ESA to delay its Rosetta mission and costing it a further €100 million.

With the combined bill for Herschel and Planck coming in at more than €2 billion, it is near-inconceivable that they will be rebuilt if something goes wrong. Their loss would leave ESA reeling. The agency has other missions in the pipeline, including a mission to Mercury and a star-mapping project called Gaia. These have excellent scientific potential but they somehow seem small in comparison.

In short, if we lose Herschel and Planck, the heart of ESA's - and arguably the world's - space science programme would be ripped out. Let us all wish ESA the very best of luck.

Herscel Planck: Ready for countdown

Herschel (left) and Planck (right) could revolutionise our understanding of the universe (Image: ESA)