Dark matter’s interaction with visible matter may have opened portal to a new kind of physics.

A team of research from Italy’s northeastern university SISSA may have found a new perception which may shed some legitimate insight into the long-lost conception of Dark Matter. The statistical studies have shown results which interconnect Dark matter with ordinary matter. The results are certainly not within the limits of the standard models of physics. The results are quite obvious but cannot be understood in a trivial way within the existing framework of the standard model. The statistical analysis of mini-spiral galaxies has shown results which may lead to a completely new kind of physics, where the phenomenon such as Dark Matter and Dark energy can be explained.

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Well, to start with what are mini-spiral galaxies, let me clarify that they are not very much different from ours and in fact resembles our galaxies, only 10 times smaller. Dark Matter has been a mystery for a long time even to some of the most prominent astrophysicists and cosmologists. Dark matter is so mysterious lies in the fact that it doesn’t emit electromagnetic radiation or even interact with it. Even using some of the most sophisticated equipment; it was only detected through its gravitational waves. Most dark matter, according to the most reliable postulates, would be non-baryonic or WIMP. It would not interact with ordinary matter except through gravitational force. But these studies have completely disagreed with this notion.

In these groundbreaking statistical study, for the first time, these elements were been studied statistically. A method was loomed which expunged the “individual” changeability of each object, thus enlightening the general characteristics of the class. A total of 36 galaxies studied, which was sufficient enough for a statistical study. By doing this an association between the structure of ordinary, or luminous matter like stars, dust, and gas, with the dark matter were found. The objects which were observed gave an outcome that the structure of the dark matter mimics the visible matter in its own way. Professor Paulo Salucci, the head of the research team explained, “If, for a given mass, the luminous matter in a galaxy is closely compacted, so it is the dark matter. Similarly, if the former is more widespread than in other galaxies, so is the latter.

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How this discovery is different when compare with the standard model of physics? Standard Model of physics deals with some of the most fundamental concepts of physics. It is one of the most generally accepted theories among the renowned physicists. It explains essential forces (particles and matters), however, it itself has some noteworthy qualms, as it does not include the gravitational force. Phenomenon such as dark matter and dark energy makes it clear to the scientists that there is yet another spot left in physics to be explored and apprehend.

From the aforementioned discussion, we can be sure that even in the largest spiral galaxies there are effects similar to the ones we observed and realize every day in our life. But they are signals that we can only explain using the outline of the Standard Model through astrophysical processes within galaxies. With mini-spirals, however, there is no simple explanation. These 36 items are the tip of the iceberg of a phenomenon that we will probably find everywhere and that will help us discover what we cannot yet see. “From our observations, the phenomenon, and thus the necessity, is incredibly obvious. At the same time, this can be a starting point for exploring this new kind of physics,” continues Salucci.

A theoretical explanation on the existence of Dark Matter

Protons, electrons, and neutrons bundled together in an atom are the particles what make most of the visible universe, including the earth, the sun and the distant stars of the galaxies. When we look up the sky, we may don that this stunning enormity mostly consists of the aforesaid particles right? Antagonistically one of the most fundamental discoveries in the 20th century was just opposite and stated that these universally accepted particles constitute less than 5% of the Universe. Yes 5%, so what about the rest 95% then? The rest of the universe is believed to be made up of an enigmatic unnoticeable material known as the dark matter along with a repelling gravitational force known as dark energy.

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What is Dark Matter is a fascinating question that gives goosebumps even to some of the finest minds in the field of astrophysics and cosmology. Dark Matter does not interact with baryonic matters and is invisible to light and other forms of electromagnetic radiation, making it impossible to detect even with the most enhanced and sophisticated instruments. So, if we cannot see it and cannot detect it, how can we be so sure of its existence? The answer lies in the gravitational effects these dark matters have on the center of the galaxies as well as the galaxy clusters. 

Standard physics states that stars on the edges of a spinning galaxy should move with a slower acceleration compare to the stars orbiting near the boundary conditions of the galactic center, where the galaxy’s visible matters are intensely concentrated. But when theoretical observations were made, it was perceived that the speed of the stars were almost same throughout the stretchable distance of the galactic disc. These observations proved the theoretical conventions that an invisible force is somehow inoculating an invisible gravitational force on the stars orbiting around the edges of a spinning galaxy thus making them accelerate much faster.

There is numerous postulate made on the dark matter and yet a few of them can explain that what it might be? One of the most fundamentally accepted postulate is that Dark matters consists of exotic particles which don’t interact with the photons and electrons but somehow exerts a gravitational pull. Other hypothesis stresses on the modified theory of gravity, which states the existence of manifold forms of gravity, and the far-reaching gravity governing galaxies which are quite different from the gravity to which we are familiar.

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The discovery of dark matter was a complete shock to the scientists. Previously they anticipated that the attractive forces of gravity will slow down the expansion of the universe w.r.t time. But little to their expectations, the simulation results send a shock of paranoia among the scientific society, when the results showed that the expansion is actually increasing instead of slowing down. It was almost as throwing a ball up the air hoping it to fall down, but only to see it going up and up. 

Physicists now believe that the expansion of the universe is due to the repulsive force engendered by the quantum fluctuations in the halo spaces of the galaxies. To be added, the force gets stronger as the universe expands and thus known as the dark force energy. Unlike dark matter, there is no conceivable explanation for dark energy and is thought to be the fifth fundamental force called quintessence, which fills the universe like a fluid. 

Dark energy is steady with the cosmological constant, a mathematical perpetual used by Albert Einstein in his equation of general theory of relativity to fit it in the impression of a stagnant universe. According to the theory, he suggested that this ‘constant’ is a reclusive force which thwarts the gravity thus preventing the galaxies from disintegrating within itself.

Now that we have discovered the universe is expanding with a dark energy in the form of a cosmological constant, we can define the true image of the stretchable space-time into vast cosmos. But even with all this explanation still, leaves the best minds wondering that why and how this strange force arrived in the first place.

Can probability help us find the answer to the beginning of the Universe?

Probability is a term which is presumably known to all human beings. If you ask people about probability, chances are they will tell you about the ’50-50’ odds of a coin getting flipped to either side of head or tail. Asking further details will fetch you answers like ‘probability of Manchester United winning the league’ or ‘probability of scientists discovering extra-terrestrial life in the Universe ’.  

If we closely analyze all the aforementioned answer we can predict that the governing rules of the probability are quite specific. Yet the exact meaning of the term is not dictionarized. When we toss a coin, how do we know that the coin is really fair? The obvious way is to get the answer is to toss it and measure the proportion of heads and tails. The laws of probability are then used to turn the measured proportion into a belief and install it in our conscious mind. Then we assume that the coin flipped is fair.

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But is this definition of probability fair? I mean ‘probability has now become a sort of subjective belief rather than objective frequencies’. In 1920, one mathematician declared the non-existence of the term probability. The apparent lack of objectivity has led him to come to such a conclusion.

Imagine what if probability does not exist. Data Analysis becomes a matter of opinion. So to avoid these horrendous situation scientists advocated techniques for analyzing experimental results that offered to use an objective measure of probability called ‘p-value’.

But with the passage of time even the concept of ‘p-value’ started to fade away and gained the critics as a nonsensical theory. Newer methods such as Bayesian method has been suggested in the recent decades. This method is comparatively more robust and has a wider range of theoretical use. Despite the vast application of probability, the concept of probability still instills doubt among many renown scientists.

How probable is our universe?

But whatever anomalies the term ‘probability’ carries, it is still regarded as one of the most advanced analyzing tool in the field of science including the Universe. So let’s see how probable our Universe is by applying the theory of probability? We have a vague idea about the creation of the Universe. As Big Bang happened around 14 billion years ago, an external inflation expanded at near about nine times the speed of light. This external inflation hypothesizes the existence of quantum forces which created rapid- expanding regions of space and time, one of which became our Universe. Given on the above facts, we can imagine how immense of a geometrical structure the universe is. Yet to our surprises, it is in fact just one of the infinite number of the bubble like Universes which constitute the totality of existence, dubbed the Multi-verse.

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Multiverse is an amazing proposal and may only be solved by applying the theories of probability. This situation is so difficult to imagine that some of the scientists don’t even want to believe the existence of multiverses. For example, using the standard definition of probability, which means dividing the total number of universes by the numbers making up the multiverses, a theorist can state the ‘probable outcome of our Universe’. But if the external inflation is happening from the very beginning, there will an infinite number of Universes like ours now. And the numbers making up the Multiverse is also infinite. Thus the whole situation of finding the probability of our universe is becoming infinite which is quite obsolete.

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This part of astrophysics has been one of the most difficult conundra to break for many scientists. One way to solve the puzzle is to assume that the forces driving the bubble universes leads them to inflate at an even higher rate as they get larger. This stretches the very fabric of space and time within the Multi-verses. But then Einstein’s light-speed limit will become archaic along with the fact that these regions will become forever undetectable due to their faster speed. It will be very tough to find the exact answers to this kind of compelling questions, but theorists are still quarreling over the details and by applying the theory of cosmic probability calculation perhaps one day we may finally arrive at the answer to the very beginning of our Universe.

 

Traces behind the birth of cosmic giants is finally been perceived

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Astrophysicists have taken a huge leap of realization in understanding the evolution of supermassive black holes. Using data from Hubble and two other space telescopes, Italian researchers have established the finest evidence yet for the seeds that eventually mature into these cosmic giants.

Year after year astronomers has researched and discussed the possible formation of the first generation supermassive black holes. They came up with many retorts but nothing came as adjacent as it seems now. Thanks to Italian scientist Fabio Pacucci whose team has identified two objects from the premature universe which could be the key to open the lock about the long-haul mystery of ‘birth of supermassive black hole’. These two substances exemplified the most promising black hole seed candidates found so far in the history of cosmological science.

With the help of NASA’s Chandra X-ray Observatory, the NASA/ESA Hubble Space Telescope, and the NASA Spitzer Space Telescope the group have been able to analyze the data from a computerized based mathematical model and finally been able to find the two substances. Both of these recently revealed black hole seed candidates seem to be less than a billion years old after the ‘Big Bang’ incident and have an initial mass of about 100 000 times the Sun.

Fundamentally, there are two main theories to explicate the formation of super massive black holes in the premature universe. The first theory suggests that the seeds grow out of black holes with a mass about ten to a hundred times larger than our Sun, as expected for the collapse of a massive star. The black hole seeds then propagated through fusions with other trivial black holes and by pulling in gas from their surroundings. However, at this stage, they have to grow at a remarkably high rate to reach the mass of super massive black holes already exposed in the billion years young universe.

The recent findings, however, contradicts some of the old theories as the results indicates that at-least some of these massive cosmic giants with mass 100 000 times greater than that of the mass of Sun formed unswervingly when a massive cloud of gas collapsed. In this circumstance, the evolution of the black holes would be galvanizing, and would ensue more quickly. This new result helps to explain why we see super massive black holes less than one billion years after the Big Bang.

A lot of controversies still prevails over which path these black holes takes, said co-author Andrea Ferrari also of Scuola Normale Superiore. “Our work suggests we are converging on one answer, where black holes start big and grow at the normal rate, rather than starting small and growing at a fast rate.”

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The picture shows a possible seed for the formation of supermassive black hole

These two newly revealed black hole seed candidates match the theoretical predictions, yet auxiliary observations are needed to confirm their true nature. To distinguish between the two formations theories, it will also be obligatory to find more candidates.

The research will be further enhanced as the team is scheduling to conduct follow-up observations in X-rays and in the infrared range. The purpose is to check the properties expected for a black hole seeds found in these two objects. Upcoming observatories, like the NASA/ESA/CSA James Webb Space Telescope and the European Extremely Large Telescope, will definitely put a dent in the field of astrophysics and cosmology, by perceiving even smaller and more distant black holes.

Simulation done on Einstein’s general theory of relativity may lead to answer why universe expands?

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The gravitational waves generated during the formation of structures in the universe is shown. The structures (distribution of masses) are shown as bright dots, gravitational waves by ellipses. the sizes of the ellipse is proportional to the amplitude of the wave and its orientation represents its polarization.

‘Universe is constantly expanding’, a statement that I hope all the astrophysicists and the cosmologists are familiar with. But the fascinating question lies in how does our universe evolve? We know that Universe merges everything that comes its way, but the topic of ‘evolution of universe’ is still a very enigmatic point in the vast field of cosmology.

But, with the discovery of Gravitational waves, all new kinds of coded simulation is going on in order to fully understand the formation of structures of the Universe. One such success is recently achieved by the physicists from the University of Geneva, where based on Einstein’s equations, they integrated the space-time rotation into their calculations and calculate the amplitude of gravitational waves, thus providing a new code of numerical simulation that offers a glimpse of the complex process of the formation of structures in the Universe.

Before the discovery of the gravitational waves, physicists studied the
formation of large-scale cosmological structures based on Newtonian gravitation. The principal of these codes hypothesizes that space itself does not change, it is said to be motionless, while time goes on. Thus, the Newtonian-based codes were applicable when the matter of the particles was moving very slowly (say about 300km per second).
However, the code failed to show accurate calculations when the speed of the matters was quite high. Moreover, the Newtonian numerical simulation does not describe dark energy’s fluctuations. Constituting 70% of the total energy of the Universe, it does not doubt that dark energy is responsible for the accelerated expansion of the Universe. Therefore, it was essential to find a new way to simulate the establishment of cosmological structures and sanction the study of these two phenomena.

Thus, Physicists from the University of Geneva successfully generated a code, named evolution and simulated the numerical codes based on Einstein’s theory of relativity. Unlike the Newtonian theory, the theory of relativity suggests that space and time are constantly changing. The most important advantage of this simulation is that now scientists can accurately calculate the fast-moving particles in space. The aim was to forecast the amplitude and the impact of gravitational waves and space-time’s rotation induced by the formation of cosmological structures.

To generate the code, the physicists analyzed a cubic part in space, consisting of 60 billion zones with each containing a particle. Thorough analyzing of particles was done with respect to their neighbors using an LATfield2 library which solves nonlinear partial differential equations. A supercomputer was also used to detect the motion of particles and calculate the metric (the measure of distances and time between two galaxies in the Universe) using Einstein’s equations. The calculations were then analyzed and compared to the Newtonian’s numerical simulation results. Finally, the effect of frame-dragging (the rotation of space-time) and gravitational waves was introduced by the formation of structure in the Universe.

It is the first time that frame-dragging and gravitational waves were being included in a numerical cosmological simulation. This operation opened a new way of testing the general theory of relativity as well as unlocking the mysteries behind Universe’s expansion.

NOTE: The above picture is copyrighted by Mr.Ruth Durrer of UNIGE.

Black Holes ejects matter into Cosmic abysses

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Cosmos is a complicated subject with a multitude of fascinating objects ranging from carbonaceous dust grains to quasars, but that don’t stop the cosmologists’ curiosity to stop thinking and researching about the most abysmal concepts of the Universe. We all live in a universe subjugated by unseen matters such as baryons, CMB photons, Cold Dark Matter (CDM), Dark Energy and all these species of the universe are concentrated into filaments that expanse around the brink of colossal voids.

Thought to be almost void until now, a group of scientists have come to conclusions that dark holes could contain as much as 20% of the ‘normal’ matter in the cosmos and that galaxies make up only 1/500th of the volume of the universe. Observing the cosmic microwave radiation and analyzing it, modern satellite observatories like COBE, WMAP and Planck have advanced our understanding of the universe’s composition. Current measurements suggest that ‘normal’ matter (i.e. the matter that makes up stars, planets, baryons, gas and dust) combine almost 4.9% of the total universe, whereas mysterious and unseen ‘dark’ matter join 26.8% and mysterious ‘dark energy’ constitute 68.3% of the universe.

Some fundamental research work mapped the positions of galaxies and their allied dark matter over large volumes, showing that they are in strings that make up a ‘cosmic web’. The scientific team explored it further, using data from the Illustris project, which is a large computer simulation of the evolution and formation of galaxies, used to measure the mass and volume of these strings and the galaxies within them.

Illustris simulates a cube of space in the universe, computing some 350 million light years on each side. It took the first variable as the age of a young universe, just 12 million years old, and the second variable was a small fraction of its current age. The data’s were simulated and the gravity and flow of matter changing the structure of the cosmos up to the present day were analysed. The simulation compacts with both normal and dark matter, with the most important effect being the gravitational pull of the dark matter.

After analyzing the data, the scientists concluded that 50% of the total mass of the universe is in the places where galaxies exist in, trampled into a volume of 0.2% of the universe we see, and a further 44% is in the enveloping strings. Just 6% is in the voids, which make up 80% of the volume.

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The most surprising thing that caught scientists’ attention were the 20% fraction of ‘normal’ matter filling up the voids. Super-massive black holes found at the center of galaxies are the reason behind this. Matters fall into the holes, thus getting converted into energy. The energy is then delivered into the surrounding gases and leads to enormous outflows of matter, expanding for hundreds of thousands of light years from the black holes, reaching far beyond the size of their host galaxies.

The result will not only help us to know about how voids with more ‘normal’ matter are filled than expected but might also explain the missing baryon problem, where astronomers do not see the amount of normal matter predicted by their models.

Further simulations using Illustris have been done, and the results are expected to come within few months, which will give us an auxiliary understanding of black holes and confirm the output. Whatever the outcome, it will be hard to see the matter in the voids, as this is likely to be fragile and too casual to emanate the X-rays that would make it detectable by satellites.

Will the discovery of Gravitational waves ever help us detect the ripples of Big Bang?

 

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Detecting ripples in a space-time was not an easy task, after-all it took 50 years of trial and error, and 25 years perfecting a set of instruments so sensitive that could finally show a distortion in space-time millions of light years away. The discovery of gravitational waves have stirred the whole world of astronomy and have posed all sort of fascinating questions for astronomers regarding binary black-hole systems. Perhaps in a way it has opened a new field of gravitational physics which will revolutionize our understanding of the universe during its infancy.

The game has just started and now that we know how to measure gravitational waves, experiments like LIGO can be further enhanced to have a broader view of events happening in and around the cosmos that we have never been able to see before, such as mergers of super-massive black holes in the early universe. But the utmost question is that how far back can we really go? What about the gravitational waves that occurred moments after the big bang, will LIGO’s discovery help us catch those?

Let us take a step back in time, we are now in an era where the masses involved in the events are large by stellar standards, they are dwarfed by the super-massive black holes that scientists believe are present at the center of almost every galaxy. Our very own galaxy, the Milky Way, hosts a hole of about 4 million sun masses, detected through the motions of stars orbiting it.

There are yet a lot to discover about these super-massive black holes. We presently understand them through the immense amounts of electromagnetic radiation, like visible light and X-rays, produced by gas cascades into them. We know the likeliness of the process of formation of black holes, where some gasses are too slow and near and others are too fast and away for the black holes to capture it. So, the intriguing questions are that how could they get so big?

The answer could be that collisions between these super-massive holes helped to grow them, particularly when they were comparatively young and had not yet gained much gas. However, a collision between two super-massive black holes can probably only happen if the two galaxies hosting them collide and merge too. But these event is impossible to happen in the current time as because galaxies are far away from each other. But what if we go back in time, a time when the universe was much younger and the galaxies were very nearer to each other.

So detecting gravitational waves from such collisions means going back in time and analyzing the most distant galaxies giving us direct traces about how important these events were in growing super-massive black holes early in their lives and in turn unraveling the truth of mystery about the universe.

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But the collision of super-massive black-holes is not the end. The Big Bang, and particularly the eon of very rapid expansion dubbed inflation with enormous masses moving with almost light speed producing powerful gravitational waves are the goal we are looking forward to achieve. However, the most powerful signal comes from masses whose size is comparable to the scale of the universe itself. Since gravitational radiation has a typical wavelength larger than the masses emitting it, the “wavelength” of this radiation is itself similar to the entire size of the universe. So LIGO, or any other experiment that is smaller than the universe, will not be able to detect it.

The challenge is extremely difficult but a positive result could give evidence for the popular inflation theory, and offer explanations for several baffling features of the universe, such as why the distribution of matter is so standardized. Although finding such a signal is a colossal challenge, so was the direct detection of gravitational waves when first proposed half a century ago.

Galactic climate being affected by Black Holes

A prevailing galactic explosion produced by a giant black hole situated almost 26 million light years away from Earth has provoked a new leap in the field of cosmology. This is one of the nearest super-massive black holes to Earth and its frequent violent outbursts can somehow change the galactic climate is been proposed by a team of researchers led by Eric Schlegel, Professor of Physics at The University of Texas at San Antonio.

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The inset image shows X-ray arcs that astronomers say are signs of galactic burping in the Messier 51 galaxy system

Schlegel’s team used NASA’s Earth-orbiting Chandra X-ray Observatory to locate the black hole blast in the famous Messier 51 system of galaxies. The Messier 51 system contains a large spiral galaxy, NGC 5194, colliding with a smaller companion galaxy, NGC 5195.

“Just as powerful storms here on Earth impact their environments, so too do the ones we see out in space,” Schlegel said. “This black hole is blasting hot gas and particles into its surroundings that must play an important role in the evolution of the galaxy.”

Schlegel and his colleagues, including Fisk University graduate student and UTSA alumna Laura Vega, detected two X-ray emission arcs near to the center of NGC 5195, where the super-massive black hole is located.

“We think these arcs represent artifacts from two enormous gusts when the black hole expelled material outward into the galaxy,” said co-author Christine Jones, astrophysicist, and lecturer at the Harvard-Smithsonian Center for Astrophysics. “We think this activity has had a big effect on the galactic landscape.”

The researchers detected a willowy region of hydrogen gas emission just beyond the outer arc, suggesting that X-ray emitting gas expatriate the hydrogen gas from the center of the galaxy.

Furthermore, the properties of the gas around the arcs propose that the outer arc has flounced up enough material to trigger the formation of new stars. This type of phenomenon, where a black hole affects its host galaxy, is called feedback. Continue reading