Old-looking galaxy in a young universe: Astronomers find dust in the early universe

This spectacular view from the NASA/ESA Hubble Space Telescope shows the rich galaxy cluster Abell 1689. The huge concentration of mass bends light coming from more distant objects and can increase their total apparent brightness and make them visible. One such object, A1689-zD1, is located in the box -- although it is still so faint that it is barely seen in this picture. New observations with ALMA and ESO's VLT have revealed that this object is a dusty galaxy seen when the Universe was just 700 million years old.  Credit: NASA; ESA; L. Bradley (Johns Hopkins University); R. Bouwens (University of California, Santa Cruz); H. Ford (Johns Hopkins University); and G. Illingworth (University of California, Santa Cruz)

Dust plays an extremely important role in the universe -- both in the formation of planets and new stars. But dust was not there from the beginning and the earliest galaxies had no dust, only gas. Now an international team of astronomers, led by researchers from the Niels Bohr Institute, has discovered a dust-filled galaxy from the very early universe. The discovery demonstrates that galaxies were very quickly enriched with dust particles containing elements such as carbon and oxygen, which could form planets. The results are published in the scientific journal, Nature.

Cosmic dust are smoke-like particles made up of either carbon (fine soot) or silicates (fine sand). The dust is comprised primarily of elements such as carbon, silicon, magnesium, iron and oxygen. The elements are synthesised by the nuclear combustion process in stars and driven out into space when the star dies and explodes. In space, they gather in clouds of dust and gas, which form new stars, and for each generation of new stars, more elements are formed. This is a slow process and in the very earliest galaxies in the history of the universe, dust had not yet formed.

But now a team of researchers have discovered a very distant galaxy that contains a large amount of dust, changing astronomers' previous calculations of how quickly the dust was formed.

"It is the first time dust has been discovered in one of the most distant galaxies ever observed -- only 700 million years after the Big Bang. It is a galaxy of modest size and yet it is already full of dust. This is very surprising and it tells us that ordinary galaxies were enriched with heavier elements far faster than expected," explains Darach Watson, an astrophysicist with the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.

Darach Watson led the project, with Lise Christensen from the Dark Cosmology Centre and researchers from Sweden, Scotland, France and Italy.

Lucky location

Because the galaxy is very distant and therefore incredibly faint, it would not usually be detectable from Earth. But a fortunate circumstance means the light from it has been amplified. This is because a large cluster of galaxies called Abell 1689, lies between the galaxy and Earth. The light is refracted by the gravity of the galaxy cluster, thus amplifying the distant galaxy. The phenomenon is called gravitational lensing and it works like a magnifying glass.

"We looked for the most distant galaxies in the universe. Based on the colours of the light observed with the Hubble Space Telescope we can see which galaxies could be very distant. Using observations from the very sensitive instrument, the X-shooter spectrograph on the Large Telescope, VLT in Chile, we measured the galaxy's spectrum and from that calculated its redshift, i.e. the change in the light's wavelength as the object recedes from us. From the redshift we can calculate the galaxy's distance from us and it turned out to be, as we suspected, one of the most distant galaxies we know of to date," explains Lise Christensen, an astrophysicist at the Dark Cosmology Centre at the Niels Bohr Institute.

Early planet formation

Darach Watson explains that they then studied the galaxy with the ALMA telescopes, which can observe far-infrared wavelengths and then it became really interesting, because now they could see that the galaxy was full of dust. He explains that young stars in early galaxies emit hot ultraviolet light. The hot ultraviolet radiation heats the surrounding ice-cold dust, which then emits light in the far-infrared.

"It is this far-infrared light, which tells us that there is dust in the galaxy. It is very surprising and it is the first time that dust has been found in such an early galaxy. The process of star formation must therefore have started very early in the history of the universe and be associated with the formation of dust. The detection of large amounts of solid material shows that the galaxy was enriched very early with solids which are a prerequisite for the formation of complex molecules and planets," explains Darach Watson.

Now the researchers hope that future observations of a large number of distant galaxies using the ALMA telescopes could help unravel how frequently such evolved galaxies occur in this very early epoch of the history of the universe.

Source: University of Copenhagen - Niels Bohr Institute

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Newborn neurons in adult brain may help us adapt to environment

Neurons . "New neurons may serve as a means to fine-tune the hippocampus to the predicted environment," Opendak says. "In particular, seeking out rewarding experiences or avoiding stressful experiences may help each individual optimize his or her own brain.
Credit: © ktsdesign / Fotolia
The discovery that the human brain continues to produce new neurons in adulthood challenged a major dogma in the field of neuroscience, but the role of these neurons in behavior and cognition is still not clear. In a review article published by Cell Press February 21st in Trends in Cognitive Sciences, Maya Opendak and Elizabeth Gould of Princeton University synthesize the vast literature on this topic, reviewing environmental factors that influence the birth of new neurons in the adult hippocampus, a region of the brain that plays an important role in memory and learning.

The authors discuss how the birth of such neurons may help animals and humans adapt to their current environment and circumstances in a complex and changing world. They advocate for testing these ideas using naturalistic designs, such as allowing laboratory rodents to live in more natural social burrow settings and observing how circumstances such as social status influence the rate at which new neurons are born.

"New neurons may serve as a means to fine-tune the hippocampus to the predicted environment," Opendak says. "In particular, seeking out rewarding experiences or avoiding stressful experiences may help each individual optimize his or her own brain. However, more naturalistic experimental conditions may be a necessary step toward understanding the adaptive significance of neurons born in the adult brain."

In recent years, it has become increasingly clear that environmental influences have a profound effect on the adult brain in a wide range of mammalian species. Stressful experiences, such as restraint, social defeat, exposure to predator odors, inescapable foot shock, and sleep deprivation, have been shown to decrease the number of new neurons in the hippocampus. By contrast, more rewarding experiences, such as physical exercise and mating, tend to increase the production of new neurons in the hippocampus.

The birth of new neurons in adulthood may have important behavioral and cognitive consequences. Stress-induced suppression of adult neurogenesis has been associated with impaired performance on hippocampus-dependent cognitive tasks, such as spatial navigation learning and object memory. Stressful experiences have also been shown to increase anxiety-like behaviors that are associated with the hippocampus. In contrast, rewarding experiences are associated with reduced anxiety-like behavior and improved performance on cognitive tasks involving the hippocampus.

Although scientists generally agree that our day-to-day actions change our brains even in adulthood, there is some disagreement on the adaptive significance of new neurons. For instance, the literature presents mixed findings on whether new neurons generated under a specific experimental condition are geared toward the recognition of that particular experience or if they provide a more naive pool of new neurons that enable environmental adaptation in the future.

Gould and her collaborators recently proposed that stress-induced decreases in new neuron formation might improve the chances of survival by increasing anxiety and inhibiting exploration, thereby prioritizing safety and avoidant behavior at the expense of performing optimally on cognitive tasks. On the other hand, reward-induced increases in new neuron number may reduce anxiety and facilitate exploration and learning, leading to greater reproductive success.

"Because the past is often the best predictor of the future, a stress-modeled brain may facilitate adaptive responses to life in a stressful environment, whereas a reward-modeled brain may do the same but for life in a low-stress, high-reward environment," says Gould, a professor of psychology and neuroscience at Princeton University.

However, when aversive experiences far outnumber rewarding ones in both quantity and intensity, the system may reach a breaking point and produce a maladaptive outcome. For example, repeated stress produces continued reduction in the birth of new neurons, and ultimately the emergence of heightened anxiety and depressive-like symptoms.

"Such a scenario could represent processes that are engaged under pathological conditions and may be somewhat akin to what humans experience when exposed to repeated traumatic stress," Opendak says.

Because many studies that investigate adult neurogenesis use controlled laboratory conditions, the relevance of the findings to real-world circumstances remains unclear. The use of a visible burrow system--a structure consisting of tubes, chambers, and an open field--has allowed researchers to recreate the conditions that allow for the production of dominance hierarchies that rats naturally form in the wild, replicating the stressors, rewards, and cognitive processes that accompany this social lifestyle.

"This more realistic setting has revealed individual differences in adult neurogenesis, with more new neurons produced in dominant versus subordinate male rats," Gould says. "Taking findings from laboratory animals to the next level by exploring complex social interactions in settings that maximize individual variability, a hallmark of the human experience, is likely to be especially illuminating."

Source: Cell Press

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Is not there Big Bang ? A quantum equation show that the universe has no beginning

The universe could have existed forever, according to a new model that applies quantum correction terms to complement the theory of general relativity of Einstein. The model can also explain dark matter and dark energy.

The widely accepted age of the universe, according to estimates of general relativity, is 13,800 million years. At first, everything was dealt a single infinitely dense point or, in other words, the singularity. After that point began to expand to trigger the Big Bang, considered the origin of the universe, has  Science Direct .

Although the Big Bang singularity arises directly and inevitably mathematics of general relativity, some scientists consider the problematic issue because mathematics can only explain what happened after and not before the singularity .

However, Ahmed Ali Farag, Benha University, Egypt, and Saurya Das University of Lethbridge, Canada, say the Big Bang singularity can be resolved by its new model in which the universe has no beginning nor end .

The researchers used Raychaudhuri equation and the Friedmann equations, which describe the expansion and evolution of the universe (including the Big Bang) in the context of general relativity. The model of Ali and Das contains elements of both quantum theory, of general relativity .

In physical terms, the model describes the universe as full of "quantum fluid" . Scientists propose that this fluid could be composed of gravitons, hypothetical massless particles that mediate the force of gravity.

To understand the origin of the universe, they analyzed the behavior of the fluid over time. Surprisingly, they found that this does not converge towards the singularity, but, on the contrary, the universe seems to have always existed . Although it was smaller in the past, says Das.

Source: RT

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The 500 million years ocean history

Brachiopod Paraspirifer bownockeri from the Middle Devonian of Ohio (USA); Width: 5.6 cm. Picture: U. Jansen, Senckenberg Museum, Frankfurt am Main.

GEOMAR coordinates European research and education project BASE-LiNE Earth
02.03.2015 / Kiel. As the history of the oceans can be reconstructed in the past 500 million based on calcareous shells of fossil marine life, busy to date with the research project BASE-LiNE Earth. At the same time it enables talented young scientists and scientists a doctorate in an international research environment. The European Union supports the at GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project with a total of 3.8 million euros.

Almost all life on earth would be extinct - and that at least five times in the past 500 million years. The environmental changes that have each led to the mass extinction, the oceans play an important role in almost all cases. How did it happen that was phased so hostile to life as a life-giving force sea? And why have some species still survive? These are fundamental questions that will be examined in the next three years as part of the European research project BASE-LiNE Earth with innovative technologies and methods. In addition to answering the research questions BASE LiNE Earth serves as the training of talented young scholars and scientists who are recruited by means of a demanding selection process from all over the world and doctorate within the scope of the project. 

The EU promotes the GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project under a Marie Skłodowska-Curie Action in Horizon2020-Pogramm with a total of 3.8 million euros. The challenge for the future BASE-LiNE Earth-doctoral students, is to provide information to gain from distant epochs of earth's history. "When historians want to know about events 100 or 200 years ago, they visit libraries or archives where there is written evidence from these times," says project coordinator Prof. Dr. Anton Eisenhauer from GEOMAR. "We also use archives. 
However, they see something different. It is, for example, the calcareous shells of fossil brachiopods in which the relevant data on the chemical history of ocean water are stored reliably, "explains the Kiel geochemist on. 

The information is in the calcite shells of course not writing before, but encrypted in the chemical and mineralogical composition. "If we precise the ratios of elements such as strontium, magnesium, boron, or measure of the isotopic to each other, we can decrypt the information," says Professor Eisenhauer.

This then the age of the shell, as well as the chemical composition of the previous ocean and prevailing environmental conditions such as water temperature and the acidity of the water can be reconstructed. We know, for example, know that during the greatest mass extinction 251 million years ago, the ocean contained no oxygen and was acidified to a large extent. 

"This is similar to some scenarios that we expect for the future of our ocean," explains Professor Eisenhauer. Model calculations are carried out within the framework of the project should show how far the former changes in the environment are transferable to the present day. The challenge is to gain this information and to make it usable. In collaboration with industry partners modern analytical methods for obtaining information in cooperation with business partners in this area in the context of BASE-LiNE Earth therefore be generated and developed. The project involves a total of 21 scientific institutions from eight European countries and partners from Canada, Israel, Palestine and Australia involved. 15 PhD positions will announce the project this spring, two of them for the GEOMAR in Kiel. 

The Integrated School of Ocean Sciences (ISOS) provides at the University of Kiel for a comprehensive training program in which the scholars not only pursue their academic goals, but also learn more professional qualifications, skills and interact with each other.  In the coming years, the parties want to do their topic also by means of exhibitions and school supplies to a wider audience. "Of course we also bind the doctoral students, which thus also learn to communicate their work understandable," says the project coordinator. For more information on the project website www.baseline-earth.eu.

Source: Geomar

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