How did the universe begin? Hot Big Bang or slow thaw?

Did the universe begin with a hot Big Bang or did it slowly thaw from an extremely cold and almost static state?

Did the universe begin with a hot Big Bang or did it slowly thaw from an extremely cold and almost static state? Prof. Dr. Christof Wetterich, a physicist at Heidelberg University, has developed a theoretical model that complements the nearly 100-year-old conventional model of cosmic expansion. According to Wetterich's theory, the Big Bang did not occur 13.8 billion years ago -- instead, the birth of the universe stretches into the infinite past. This view holds that the masses of all particles constantly increase. The scientist explains that instead of expanding, the universe is shrinking over extended periods of time.

Cosmologists usually call the birth of the universe the Big Bang. The closer we approach the Big Bang in time, the stronger the geometry of space and time curves. Physicists call this a singularity -- a term describing conditions whose physical laws are not defined. In the Big Bang scenario, the spacetime curvature becomes infinitely large. Shortly after the Big Bang, the universe was extremely hot and dense. Prof. Wetterich believes, however, that a different "picture" is also possible. If the masses of all elementary particles grow heavier over time and gravitational force weakens, the universe could have also had a very cold, slow start. In that view, the universe always existed and its earliest state was virtually static, with the Big Bang stretching over an infinitely long time in the past. The scientist from the Institute for Theoretical Physics assumes that the earliest "events" that are indirectly observable today came to pass 50 trillion years ago, and not in the billionth of a billionth of a billionth of a second after the Big Bang. "There is no longer a singularity in this new picture of the cosmos," says Prof. Wetterich.
His theoretical model explains dark energy and the early "inflationary universe" with a single scalar field that changes with time, with all masses increasing with the value of this field. "It's reminiscent of the Higgs boson recently discovered in Geneva. This elementary particle confirmed the physicists' assumption that particle masses do indeed depend on field values and are therefore variable," explains the Heidelberg scientist. In Wetterich's approach, all masses are proportional to the value of the so-called cosmon field, which increases in the course of cosmological evolution. "The natural conclusion of this model is a picture of a universe that evolved very slowly from an extremely cold state, shrinking over extended periods of time instead of expanding," explains Prof. Wetterich.
Wetterich stresses that this in no way renders the previous view of the Big Bang "invalid," however. "Physicists are accustomed to describing observed phenomena using different pictures." Light, for example, can be depicted as particles and as a wave. Similarly, his model can be seen as a picture equivalent to the Big Bang. "This is very useful for many practical predictions on the consequences that arise from this new theoretical approach. However, describing the 'birth' of the universe without a singularity does offer a number of advantages," emphasises Prof. Wetterich. "And in the new model, the nagging dilemma of 'there must have been something before the Big Bang' is no longer an issue."

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Journal References:

1. C. Wetterich. Variable gravity Universe. Physical Review D, 2014; 89 (2) DOI: 10.1103/PhysRevD.89.024005
2. C. Wetterich. Universe without expansion. Physics of the Dark Universe, 2013; 2 (4): 184 DOI: 10.1016/j.dark.2013.10.002

How the universe has cooled since the Big Bang fits Big Bang theory

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

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 CSIRO 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 half-way into the Universe's history, we need to look half-way across the Universe.
How can we measure a temperature at such a great distance?
The astronomers studied gas in an unnamed galaxy 7.2 billion light-years away [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).
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. The Universe of a few billion years ago was a few degrees warmer than it is now, exactly as the Big Bang Theory predicts," said research team leader Dr Sebastien Muller of Onsala Space Observatory at Chalmers University of Technology in Sweden.

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The above story is based on materials provided by CSIRO Australia. Note: Materials may be edited for content and length.

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Journal Reference:

1. S. Muller , A. Beelen, J. H. Black, S. J. Curran, C. Horellou, S. Aalto, F. Combes, M. Guelin, C. Henkel. A precise and accurate determination of the cosmic microwave background temperature at z=0.89. Astronomy & Astrophysics, 2013 [link]

How does the universe creates reason, morality?

Solar system

Recent developments in science are beginning to suggest that the universe naturally produces complexity. The emergence of life in general and perhaps even rational life, with its associated technological culture, may be extremely common, argues Clemson researcher Kelly Smith in a recently published paper in the journal Space Policy.

What's more, he suggests, this universal tendency has distinctly religious overtones and may even establish a truly universal basis for morality.
Smith, a Philosopher and Evolutionary Biologist, applies recent theoretical developments in Biology and Complex Systems Theory to attempt new answers to the kind of enduring questions about human purpose and obligation that have long been considered the sole province of the humanities.
He points out that scientists are increasingly beginning to discuss how the basic structure of the universe seems to favor the creation of complexity. The large scale history of the universe strongly suggests a trend of increasing complexity: disordered energy states produce atoms and molecules, which combine to form suns and associated planets, on which life evolves. Life then seems to exhibit its own pattern of increasing complexity, with simple organisms getting more complex over evolutionary time until they eventually develop rationality and complex culture.
And recent theoretical developments in Biology and complex systems theory suggest this trend may be real, arising from the basic structure of the universe in a predictable fashion.
"If this is right," says Smith, "you can look at the universe as a kind of 'complexity machine', which raises all sorts of questions about what this means in a broader sense. For example, does believing the universe is structured to produce complexity in general, and rational creatures in particular, constitute a religious belief? It need not imply that the universe was created by a God, but on the other hand, it does suggest that the kind of rationality we hold dear is not an accident."
And Smith feels another similarity to religion are the potential moral implications of this idea. If evolution tends to favor the development of sociality, reason, and culture as a kind of "package deal," then it's a good bet that any smart extraterrestrials we encounter will have similar evolved attitudes about their basic moral commitments.
In particular, they will likely agree with us that there is something morally special about rational, social creatures. And such universal agreement, argues Smith, could be the foundation for a truly universal system of ethics.
Smith will soon take sabbatical to lay the groundwork for a book exploring these issues in more detail.

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The above story is based on materials provided by Clemson University. Note: Materials may be edited for content and length.

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Journal Reference:

1. Kelly C. Smith. Manifest complexity: A foundational ethic for astrobiology? Space Policy, 2014; 30 (4): 209 DOI: 10.1016/j.spacepol.2014.10.004

Dynamic, dark energy in an accelerating universe | sci-english.blogspot.com

Irene Sendra-Server, PhD holder in Physics and research scientist in the UPV/EHU’s Department of Theoretical Physics and History of Science | sci-english.blogspot.com

The models proposed by the UPV/EHU-University of the Basque Country researcher are contributing towards understanding the nature of dark energy.

It was cosmology that drew Irene Sendra from Valencia to the Basque Country. Cosmology also gave her the chance to collaborate with one of the winners of the 2011 Nobel Prize for Physics on one of the darkest areas of the universe. And dark matter and dark energy, well-known precisely because so little is known about them, are in fact the object of the study by Sendra, a researcher in the Department of Theoretical Physics and History of Science of the UPV/EHU's Faculty of Science and Technology.
"Observations tell us that about 5% of the universe is made up of ordinary matter; 22% corresponds to dark matter, which we know exists because it interacts gravitationally with ordinary matter; another 73% is dark energy, which is known to be there because otherwise one would not be able to account for the accelerating expansion of the universe," explains Irene Sendra; "We are trying to find out a bit more about what dark energy is," she adds.
If dark energy did not exist, the gravitational pull exerted by matter would slow down the expansion of the universe, but observations have concluded that the opposite is the case.Dark energy is what makes the universe expand in an accelerating way, and contributing towards understanding its nature is the basis of the research Sendra has done as part of her PhD thesis entitled: "Cosmology in an accelerating universe: observations and phenomenology."
The research starts with the hypothesis that dark energy could be dynamic.The most widely accepted model, known as the Lambda-CDM, explains the acceleration of the universe by means of the cosmological constant, whose equation of state would have a value of -1, constant throughout the whole evolution of the universe.However, there are observations which this model cannot account for."We look for a dynamic, dark energy that would vary over time; we apply various models to the observable data, we play around with small disturbances, and we see whether they adapt better than a constant," explains Sendra.
Making use of mathematical and statistical tools, the values that the observation proposes for the parameters studied are compared with those proposed by the model."So,throughmany iterations, we can see which values would take the constants of our model.The equation of state of dark energy is worth practically -1 now, but it appears to have evolved from different values in the past; however, there is still a high percentage of error in determining these values."According to Sendra's calculations, these data are consistent with dynamic dark energy, which would vary with the redshift observed in the universe.Results that have yet to be published and obtained in collaboration with Adam Riess, the 2011 Nobel Prize Winner for Physics, go further in that direction.
In this PhD thesis, besides studying the equation of state of dark energy, a new model has been proposed and it would unite dark energy with dark matter.As Sendra explains, "They could be the same thing that is manifested in a different way depending on the context; we have explained the effect of both of them through one single component, and the observations give better results in this model than in others that try to unite matter and dark energy."
Finally, Sendra has peered at the oldest universe by means of the study of its cosmic microwave background."It is the most distant proof we have of the universe," she comments, "and the study of it tells us that the actual number of neutrinos is higher than three.Nevertheless, what we know for a fact, through the standard model of particles, is that there are three kinds of neutrinos.We have ended up with a somewhat strange value, so we are trying to account for that excess in the number of neutrinos." Sendra's proposal is heading in the direction of the string theory. According to her results, this neutrino excess could be interpreted as the contribution of primordial gravitational waves, caused by the interaction of cosmic strings at the time when the cosmic microwave background was produced.

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The above story is based on materials provided by Basque Research. Note: Materials may be edited for content and length.

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3-D map of the adolescent universe | sci-english.blogspot.com

3D map of the cosmic web at a distance of 10.8 billion years from Earth | sci-english.blogspot.com

 

Using extremely faint light from galaxies 10.8-billion light years away, scientists have created one of the most complete, three-dimensional maps of a slice of the adolescent universe. The map shows a web of hydrogen gas that varies from low to high density at a time when the universe was made of a fraction of the dark matter we see today.

The new study, led by Khee-Gan Lee and his team at the Max Planck Institute for
Astronomy in conjunction with researchers at Berkeley Lab and UC Berkeley, will be
published in an upcoming issue of Astrophysical Journal Letters.
In addition to providing a new map of part of the universe at a young age, says David Schlegel of Berkeley Lab, the work demonstrates a novel technique for high-resolution universe maps. The new technique, which uses distant galaxies to backlight hydrogen gas, might inform future mapping projects, he says. One such project could be the proposed Dark Energy Spectroscopic Instrument (DESI). Managed by Berkeley Lab, DESI has the goal of producing the most complete map of the universe yet.
"DESI was designed without the possibility of extracting such information from the most distant, faint galaxies," says Schlegel, "Now that we know this is possible, DESI promises to be even more powerful."
The first big 3D map of the universe was created using data from the Sloan Digital Sky Survey (SDSS), which began in 1998. Over the years, the survey has provided data to make a high-resolution map of the nearby universe, within about 1-billion light years. Recent telescope upgrades have stretched our ability to map the universe to about 6-billion light years, but, according to Schlegel, it's a fairly crude map with incomplete data in some areas. The next generation of maps will come from the DESI project, scheduled to begin operation in 2018 pending funding. DESI will allow scientists to visualize 10 times the volume of SDSS and will extend about 10-billion light years away.
Artist's impression illustrating the technique of Lyman-alpha tomography: as light from distant background galaxies (yellow arrows) travel through the Universe towards Earth, they are imprinted by the absorption signatures from hydrogen gas tracing in the foreground cosmic web. By observing a number of background galaxies in a small patch of the sky, astronomers were able to create a 3D map of the cosmic web using a technique similar to medical computer tomography (CT) scans. Credit: Khee-Gan Lee (MPIA) and Casey Stark (UC Berkeley)
Beyond 10-billion light years, says Schlegel, the expectation was that the map would become sparse. The reason: astronomers planned to use a familiar technique that uses the bright light of quasars, which are, unfortunately, scattered and few. The technique uses a phenomenon called Lyman-alpha forest absorption, which relies on the fact that vast clouds of hydrogen exist between Earth and distant quasars and galaxies. At a certain distance, as measured by the red shift of the light, astronomers can determine the density of hydrogen, based on the absorption of quasar light. The problem is that this only provides information about the presence of hydrogen along the line of sight, not over a larger volume of space.
"It's a pretty weird map because it's not really 3D," explains Schlegel. "It's all these skewers; we don't have a picture of what's between the quasars, just what's along the skewers."
The researchers believe their new technique, which uses the faint light of numerous distant galaxies instead of that of sparse quasars, can fill in the gaps between these skewers.
Before this study, no one knew if galaxies further than 10-billion light years away could provide enough light to be useful, Schlegel says. But earlier this year, the team collected four hours of data on the Keck-1 telescope during a brief break in cloudy skies. "It turned out to be enough time to prove we could do this," Schlegel says.
Of course, the galaxies' light was indeed exceedingly faint. In order to use it for a map, the researchers needed to develop algorithms to subtract light from the sky that would otherwise drown out the galactic signals. Schlegel developed the algorithm to do this, while Casey Stark and Martin White of UC Berkeley modified an existing algorithm, called a Wiener filter, to create the 3D map within a minute on a standard laptop computer.
Because the project was a proof-of-concept, the researchers are planning future Keck-1 telescope time to extend the volume of space they map. "This technique is pretty efficient and it wouldn't take a long time to obtain enough data to cover volumes hundreds of millions of light years on a side," says Khee-Gan Lee.
This research was supported by the U.S. Department of Energy's Office of Science and used the facilities of the National Energy Research Scientific Computing Center (NERSC) located at Berkeley Lab.
- See more at: http://newscenter.lbl.gov/2014/10/16/a-3d-map-of-the-adolescent-universe/#sthash.nCKqf8Tn.dpuf

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The above story is based on materials provided by Berkeley Laboratory. The original article was written by Kate Greene. Note: Materials may be edited for content and length.

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