Fundamental forces are different depending on the region of space!

EarthSky

Data collected from a quasar 13 billion light-years away suggest a discrepancy between measurements of fundamental forces on Earth and those in that region.

Scientists have observed over time the existence of four fundamental forces: electromagnetism, gravity, strong nuclear force and weak nuclear force. A study that gathered data from a number of previous studies concluded that electromagnetism has values ​​that vary depending on the region of the universe in which it is measured, and this has a number of implications for how we understand the universe.

Starting from these differences in the values ​​of electromagnetism, scientists have theorized that they have a kind of north and south poles, which show the direction in which these variations can be mapped. "The new study seems to support this idea that there could be a directionality in the Universe, which is really very strange. So the universe may not be isotropic in its physical laws to be the same, statistically, in all directions, ”explains James Webb, a researcher at the University of New South Wales in Australia.

"But, in fact, there could be a certain direction or preferred direction in the Universe where the laws of physics change, but not in a perpendicular direction. In other words, the Universe has, in a certain sense, a dipole structure ", explains the researcher.

The data collected in this study call into question the theories and explanatory models that scientists currently use to explain how the universe evolves and various phenomena occur. "Our standard model of cosmology is based on an isotropic universe, one that is statistically the same in all directions. This standard model is built on Einstein's theory of gravity, which explicitly assumes the constancy of the laws of nature, "adds Webb.


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The study was published in Science Advances.

The new supercomputer “Minerva” has been put into operation at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI).

The new supercomputer “Minerva” has been put into operation at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI). 

With 9,504 compute cores, 38 TeraByte memory and a peak performance of 302.4 TeraFlop/s it is more than six times as powerful as its predecessor. The scientists of the department “Astrophysical and Cosmological Relativity” can now compute significantly more gravitational waveforms and also carry out more complex simulations.

Minerva is to solve Einstein’s equations

Above all, the new computer cluster – named after the Roman goddess of wisdom – is used for the calculation of gravitational waveforms. These ripples in space time – measured for the first time directly in September 2015 – originate when massive objects such as black holes and neutron stars merge. Obtaining the exact forms of the emitted gravitational waves requires numerically solving Einstein’s complicated, non-linear field equations on supercomputers like Minerva. The AEI has been at the forefront of this field for many years and its researchers have been making important contributions to the software tools of the trade.

Tracking down faint signals in the detectors’ background noise and inferring information about astrophysical and cosmological properties of their sources requires calculating the mergers of many different binary systems such as binary black holes or pairs of a neutron star and a black hole, with different combinations of mass ratios and individual spins.

“Such calculations need a lot of compute power and are very time-consuming. The simulation of the first gravitational wave measured by LIGO lasted three weeks – on our previous supercomputer Datura,” says AEI director Professor Alessandra Buonanno. “Minerva is significantly faster and so we can now react even quicker to new detections and can calculate more signals.”

Ready for the gravitational wave detectors’ second science run
The gravitational wave detectors Advanced LIGO in the USA (aLIGO) and GEO600 in Ruthe near Hanover started their second observational run (“O2”) on 30 November 2016. aLIGO is now more sensitive than ever before: The detectors will be able to detect signals from about 20% further away compared to O1, which increases the event rate by more than 70%.

Credit : mpg.de

Numerical simulation of the gravitational-wave event GW151226 associated to a binary black-hole coalescence. The strength of the gravitational wave is indicated by elevation as well as color, with cyan indicating weak fields and orange indicating strong fields. The sizes of the black holes as well as the distance between the two objects is increased by a factor of two to improve visibility. The colors on the black holes represent their local deformation due to their intrinsic rotation (spin) and tides.


 Numerical-relativistic Simulation: S. Ossokine , A. Buonanno (Max Planck Institute for Gravitational Physics) and the Simulating eXtreme Spacetime project; scientific visualization: T. Dietrich, R. Haas (Max Planck Institute for Gravitational Physics)

Researchers in the Astrophysical and Cosmological Relativity division at AEI have improved the capabilities of aLIGO detectors to observe and estimate parameters of gravitational-wave sources ahead of O2. For the search for binary black hole mergers, they have refined their waveform models using a synergy between numerical and analytical solutions of Einstein’s equations of general relativity. They calibrated approximate analytical solutions (which can be computed almost instantly) with precise numerical solutions (which take very long even on powerful computers). This allows the AEI researchers to use the available computing power more effectively and to search more quickly and discover more potential signals from merging black holes in O2, and to determine the nature of their sources. AEI researchers also have prepared simulations of merging neutron star and boson star binaries. These can be simultaneously observed in electromagnetic and gravitational radiation, and can provide new precise tests of Einstein’s theory of general relativity.

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• The First Stars in the Universe could provide clues about Dark Matter

• Astronomers issued a shocking theory about the universe: 'The Universe is Flat!'

• The universe: Reading the future from the distant past

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The above post is reprinted from materials provided by Mpg . Note: Materials may be edited for content and length.

Erik Verlinde's New Theory Of Gravity Tries To Explain Dark Matter

Collage of six cluster collisions with dark matter maps. The clusters were observed in a study of how dark matter in clusters of galaxies behaves when the clusters collide Photo: wikipedia.org

Although gravity is the most familiar force of the universe, it is a thorny problem for theoretical physicists as it has long defied its inclusion in quantum mechanics. Another problem is dark matter only interacts with gravity and also defies the standard model of particle physics.

Professor Erik Verlinde, a researcher from the Delta Institute for Theoretical Physics in Amsterdam, believes that gravity is not an actual force of the universe but an effect due to the increasing entropy of the universe. In his latest paper, which is available on arXiv but is yet to be peer-reviewed, the scientist claimed that this “emergent” (and not real) force of gravity has a dark component that behaves like dark matter.

Mysterious Universe: Super Force Mysterious Universe

Photo: quantumdiaries.org

"We have evidence that this new view of gravity actually agrees with the observations," said Verlinde in a statement. "At large scales, it seems, gravity just doesn't behave the way Einstein's theory predicts."

Erik Verlinde, Theoretical Physicist at Amsterdam

Quite the bold statement from the researcher, especially since it has been shown that Einstein’s general relativity agrees quite well with large-scale observations. In the paper, Verlinde admits that the idea of this dark gravitational component needs to answer several questions before it is able to be as successful at explaining the early universe and large scale cosmology as the current theory of gravity.

The theory of entropic gravity was first proposed by Verlinde in a paper in 2010 and published in the Journal of High Energy Physics in 2011. The proposed idea was welcomed by some as a novel approach to the problem of gravity in quantum mechanics.

Verlinde's new theory of gravity passes first test Phys.org

Others were more skeptical and devised ways to see if gravity could really be an emergent phenomenon. In 2011, Archil Kobakhidze of the University of Melbourne looked at how gravity affects fundamental particles. His findings strongly support the idea that gravity is a real force.

Entropic gravity is appealing because it is able to reproduce the laws of Newtonian gravitation and Einstein field equations from the first thermodynamics and quantum mechanical principles, but the theory itself doesn’t make predictions so it can’t be falsified.

Einstein’s general relativity is constantly being tested, and discoveries like gravitational waves have only strengthened its role as the best theory of gravity we currently possess.


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The above post is reprinted from materials provided by IFL Science . Note: Materials may be edited for content and length.

Do Black Holes have a back door?

Credit: NASA/CXC/M.Weiss

One of the biggest problems when studying black holes is that the laws of physics as we know them cease to apply in their deepest regions. Large quantities of matter and energy concentrate in an infinitely small space, the gravitational singularity, where space-time curves towards infinity and all matter is destroyed. Or is it? A recent study by researchers at the Institute of of Corpuscular Physics (IFIC, CSIC-UV) in Valencia suggests that matter might in fact survive its foray into these space objects and come out the other side.

Published in the journal Classical and Quantum Gravity, the Valencian physicists propose considering the singularity as if it were an imperfection in the geometric structure of space-time. And by doing so they resolve the problem of the infinite, space-deforming gravitational pull.

Credit: NASA/CXC/M.Weiss

"Black holes are a theoretical laboratory for trying out new ideas about gravity," says Gonzalo Olmo, a Ramón y Cajal grant researcher at the Universitat de València (University of Valencia, UV). Alongside Diego Rubiera, from the University of Lisbon, and Antonio Sánchez, PhD student also at the UV, Olmo's research sees him analysing black holes using theories besides general relativity (GR).

Specifically, in this work he has applied geometric structures similar to those of a crystal or graphene layer, not typically used to describe black holes, since these geometries better match what happens inside a black hole: "Just as crystals have imperfections in their microscopic structure, the central region of a black hole can be interpreted as an anomaly in space-time, which requires new geometric elements in order to be able to describe them more precisely. We explored all possible options, taking inspiration from facts observed in nature."

Using these new geometries, the researchers obtained a description of black holes whereby the centre point becomes a very small spherical surface. This surface is interpreted as the existence of a wormhole within the black hole. "Our theory naturally resolves several problems in the interpretation of electrically-charged black holes," Olmo explains. "In the first instance we resolve the problem of the singularity, since there is a door at the centre of the black hole, the wormhole, through which space and time can continue."

This study is based on one of the simplest known types of black hole, rotationless and electrically-charged. The wormhole predicted by the equations is smaller than an atomic nucleus, but gets bigger the bigger the charge stored in the black hole. So, a hypothetical traveller entering a black hole of this kind would be stretched to the extreme, or "spaghettified," and would be able to enter the wormhole. Upon exiting they would be compacted back to their normal size.

Seen from outside, these forces of stretching and compaction would seem infinite, but the traveller himself, living it first-hand, would experience only extremely intense, and not infinite, forces. It is unlikely that the star of Interstellar would survive a journey like this, but the model proposed by IFIC researchers posits that matter would not be lost inside the singularity, but rather would be expelled out the other side through the wormhole at its centre to another region of the universe.

Another problem that this interpretation resolves, according to Olmo, is the need to use exotic energy sources to generate wormholes. In Einstein's theory of gravity, these "doors" only appear in the presence of matter with unusual properties (a negative energy pressure or density), something which has never been observed. "In our theory, the wormhole appears out of ordinary matter and energy, such as an electric field" (Olmo).

Credit: NASA/CXC/M.Weiss

The interest in wormholes for theoretical physics goes beyond generating tunnels or doors in spacetime to connect two points in the Universe. They would also help explain phenomena such as quantum entanglement or the nature of elementary particles. Thanks to this new interpretation, the existence of these objects could be closer to science than fiction.


Other articles on the same theme:

• New Theory Of Gravity Tries To Explain Dark Matter

• What form does the atomic nucleus? New discovery may explain the mysteries of the Universe.

• The First Stars in the Universe could provide clues about Dark Matter

• Astronomers issued a shocking theory about the universe: 'The Universe is Flat!'

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The above post is reprinted from materials provided by sciencedaily . Note: Materials may be edited for content and length.