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rayleigh taylor instability

Researchers demonstrate gravitational instability in granular materials for the first time

Natural phenomenon such as volcanoes and mudslides can be explained by the movement of granular particles like sand. This time engineers illustrated how bubbles are formed in the sand of lighter grain as same as other liquids even though powder materials move towards each other when mixed. Though grains present in the sand are solid when the huge volume is mixed it behaves like a liquid. Falling sand dunes or sand flowing through an hourglass are known as granular materials and the science of how they flow is still unknown.

Rayleigh-Taylor instability a mechanism in fluid dynamics explains the reason that it happens between two fluids having different densities and the light fluid thrusts the heavy fluids just like oil comes up when mixed with water. Engineers of Columbia University and ETH Zurich had discovered something likely. Chris Boyce of Columbia University, a chemical engineer said that they think their discovery can be transformed. The group discovered that upwards gas flow between granular material and vibration both produces a process alike RT instability. The study has been published in the Proceedings of the National Academy of Sciences In this process, the lighter grain starts to move upwards in between heavier grains forming fingers and bubbles. 

This works just like oil and water but they never mix whereas sand mixes. The bubbles are formed because the group of lighter grain allows the gas to flow through it easier than the heavier grains which rise the tension of the upward drag force and downward contact forces created by gas flow which creates RT instability making the results similar to that of RT instabilities in liquid but the process is different.

The researchers also noticed captivating things like the cascade branch of a descending granular droplet as mentioned in their paper. The weight of the droplets moving downwards of the heavier grains create a chain of force downwards thus not letting the drops to pass through. So the droplets break into branches while moving downwards creating somewhat similar to lightning. Another discovery was the instability similar to RT can occur when there is a huge range of flow of gas and conditions of vibration which can be used as a help in understanding the role of subterranean processes at the time of earth tremors.

Boyce said that their discovery can not only be used to describe the process of the formation of mineral deposits and geological formations but also in technologies of powder-processing in the energy, pharmaceuticals industries, and constructions. Thus we can conclude that the study of bubbles is helping to find out new things behind geological factors.

peltier effect internal

Scientists able to demonstrate cooling without additional energy consumption

Scientists from the University of Zurich have come up with a very simple device which allows the flow of heat from a cold object to a warm one without the help of any external source of power. At first glance, it seems that the fundamental law of physics is violated here. The study has been published in the Science Advances journal.

We have always known that when we keep a hot object it gradually cools down. For example, if we keep a teapot containing hot water on a table, after some time the temperature will cool down to that of the table, it would not fall farther. This is a demonstration of the second law of thermodynamics, which states that entropy of a closed system always increases. That means heat flows from a hot to a cold object, not the other way.

However, apparently, the results of the experiment conducted by Andreas Schilling, professor of Physics at the University of Zurich appears to violate the second law of thermodynamics. Researchers were able to cool the temperature of a piece of copper weighing nine grams from more than 100 degrees to much below than the room temperature without using any additional power source. Schilling says that a theoretical model of the device can transform boiling water into ice without using any amount of energy.

For getting this result, scientists used the Peltier element, which is normally used for cooling minibars. The element can act as a heat pump and transfer heat from one side to another with the help of electric current, depending on its direction. It has been previously used in experiments such as in electrical inductor for developing an oscillating heat current which keeps on changing direction. Heat flows from a cold to a hot object hence the temperature of the colder object further goes down.

Researchers have demonstrated that thermal oscillating circuit can also work in a passive manner. Without any external power supply, the flow of heat took place from a cold copper piece to a warm heat bath of temperature 22 degrees, without any transformation to other forms of energy. It did not violate the law of thermodynamics as it was shown that entropy of the entire system increased with time.

As the commercial Peltier was used, the temperature difference of only 2 degrees was recorded compared to the ambient temperature. Scientists claim that if the ideal Peltier (yet to discovered) could be used, cooling up to -47 degrees is possible. For a larger scale application, the efficiency of Peltier elements has to be increased.

cms higgs event

Scientists develop technique to trap dark particle inside LHC

For a long time, scientists have declared that we are surrounded by dark matter and dark energy which helps in binding the galaxy together. Yet they have not been able to spot them directly. Liano Wang who researches on finding signals in large particle accelerators at LHC and a physics professor at the University of Chicago says that they are confident that there is a dark world where the energy is powerful than ours.

Researchers from the University of Chicago and the university affiliated Fermilab have reported the findings in Physical Review Letters. They have found a creative way of tracing dark matter. They separate the dark particle which they see frequently interacting with normal matter. Researchers estimate that the particles which aren’t yet discovered are big and have longer life span than the particles which are already discovered. Researchers know that the particles can be easily caught when the LHC creates the collision and the number of collisions is measured.

95% or above of the universe is made of the dark world and scientists know it from the effects it creates. The effects are just like supernatural activities we can see it only when something unnatural happens. For example, we know there is a dark matter when we see all galaxies held together and gravity doing its work.

According to the previous research on the working pattern of the universe, Wang said that the particles which have a longer lifespan are somewhat related to Higgs Boson and they are the doorway to the dark world and the Higgs can decompose into these particles. So the problem here is how to rectify the events from all the other events since its very difficult to find out the particles after a collision because more than a billion collisions take place within a second and the subatoms gets scattered in every possible direction. 

Lin said that if it’s heavier then it would fetch the energy to be produced and so the momentum would be low and it would move slower than the speed of light. Researchers can easily twist their algorithm to separate particles that have a longer life span and decompose slower than the remaining subatomic shrapnel. Scientists search for the time difference of less than a billionth of second and they are optimistic towards the LHC censors that they are responsive enough to complete the job. LHC instruments are being updated so that when the collider attacks take place in 2021 they search for the slowly decaying particles.

Einstein in 1921 by F Schmutzer

Einstein’s theory of relativity confirmed by first-ever black hole image

The first-ever image of a black hole released by the Event Horizon Telescope has once again proved Einstein’s general theory of relativity to be correct. Avery Broderick, of the University of Waterloo and Perimeter Institute, Canada, who was also in the EHT team mentioned in the press in Washington that the century-old theory of general relativity put forward by Einstein passed a crucial test, spanning from the horizon to the stars.

In his theory, Einstein gave the description of gravity as a geometric property of both space and time. To be specific, the spacetime curvature is related to the momentum and energy of the matter and radiation which are present. After he published the special theory of relativity, Einstein began work on how he can include gravity in his relativistic approach. It took him almost a decade to find a relativistic approach to the gravitational forces. And the culmination of his work are the Einstein field equations which he presented to the Prussian Academy of Science.

The relativity theory predicts that whenever the ratio of the mass of an object to its radius is very very large, it leads to the formation of the black hole. This is a region from which nothing can escape including light. It also predicts that each of these black holes has an event horizon which is almost circular and of a size which can be predicted by the mass of black holes. The event horizons are the boundaries which demarcate one region from the remaining spacetime.

Black hole first image captured

Image from Event Horizon Telescope revealing the gargantuan black hole at the heart of galaxy Messier 87 (Credits – Wikimedia Commons)

And this is exactly what we see in the images of the black hole released by EHT. It shows the silhouette of a black hole at the centre of M87, a giant galaxy which is 55 million light years away from Earth. The event horizon in the image is nearly circular and the calculated mass also matches due to the massive distance. The mass of the black hole is 6.5 billion times that of our sun which is pretty big number even by standards of supermassive black holes.

This is not the first time that Einstein’s theory has been successfully verified, but it has survived the challenge posed by many experiments in the past century. A very recent example is that the general relativity predicts that objects with a very large mass and travelling at a great speed generate ripples in space-time called gravitational waves. And they were confirmed in 2015 by the Laser Interferometer Gravitational Wave Observatory(LIGO) which detected the ripples generated between two black holes.

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katie bouman the woman behind the first black hole image

Know the woman behind the first photo of black hole, Katie Bouman

On Wednesday, scientists released the first ever images of a black hole, about which we have known for a very long period of time, but could not capture a single image of it. This remarkable achievement has been made possible largely due to the algorithms created by a 29 year old computer scientist, Katie Bouman.

Katie Bouman, a doctorate from the Massachusetts Institute of Technology in Electronic Engineering and Computer Science developed an algorithm named as Continuous High-resolution Image Reconstruction using Patch priors or CHIRP. This algorithm along with CLEAN helped in obtaining the image of the black hole inside the galaxy Messier 87.

She grew up in West Lafayette, Indiana and she had learned about the Event Horizon Telescope back in 2007 while she was in school. After that, she studied Electrical Engineering from University of Michigan and went on to earn a Master’s degree from the Massachusetts Institute of Technology where she eventually earned her doctorate. At MIT, her master’s thesis was awarded the Ernst Guillemin award for the best thesis. It was after this that she joined Harvard University as a fellow on the imaging team of Event Horizon Telescope.

The Event Horizon Telescope, a collection of eight interlinked telescopes located in various parts of the world ranging from Hawaii to Antarctic captured the black hole using a technique called interferometry. The data obtained from these telescopes were collected in hard drives and then sent to a central processing centre. Dr. Bouman led the efforts in the testing process where the algorithms were used with various assumptions fed into them for extracting the image from the data. This did not mark the end of the process as the results produced by the algorithms were separated checked by several teams for the final verification. The size of the black hole is larger than that of our entire solar system and it measures 40 billion kilometres across which is three million times the size of our planet.

Dr. Katie Bouman acknowledged the efforts of all the researchers, mathematicians and engineers in this project as she said that it was because of this collaboration that this once thought impossible task was finally achieved.

Bouman now will start her new job as an assistant professor at the California Institute of Technology. But that does not end her journey with the black holes. She plans on working with the Event Horizon team to be able to produce a video on the black holes in addition to the existing images.

Speed of light measurement device

Scientists develop techniques to manipulate speed of light

A group of researchers at the University of Central Florida have developed a technique to be able to control the velocity of light. Through this technique they can not only increase the speed of light pulse and decrease it, but they can also make it travel backwards. The results were published in Nature Communications.

This finding is a significant step in the research which can someday lead to the development of highly efficient optical communication techniques. The problems of data congestion and information loss can also be handled with this result. Currently, networks use congestion control and congestion avoidance techniques to avoid these problems. More and more devices are going online everyday and advanced techniques like these will be of prime importance in the future. With fall in the prices of data consumption, people in developing countries are getting easier access to data like never before.

There have been many attempts in the past to control the speed of light. For example, light was passed through different media to adjust the speed. The major breakthrough in this experiment is that speed of light can be adjusted in the open for the first time, without using any pass-through media to increase or decrease its speed.

Ayman Abouraddy, professor in UCF’s College of Optics and Photonics who is also a co-author of this study remarked that this is the first clear demonstration of controlling the speed of the light and this will open up many areas of possibilities not explored before. This is done in a simple, reliable and repetitive way which is an important aspect.

Scientists could speed up the light upto 30 times of its normal speed, reduce to half of the speed of light and also make the pulse travel backwards. The researchers managed to develop the technique with the help of a special device called as the phase-only spatial light modulator (SLM). This helps to combine the space and time properties of light, thus making it possible to manipulate the velocity of light.

SLM was used to sculpt the spatio-temporal spectrum in an efficient manner and thus modify the group velocity. When the researchers manipulated the spatial and temporal degrees of freedom simultaneously, they found out that the group velocities were varying arbitrarily, sometimes more than the speed of light and sometimes less. They were also propagating in the forward direction away from the source and even travelling backward.

The mixing of the two main properties of light was essential to the success and scientists hope that these results can be used in a fruitful way in the future.

 

inflation after bigbang

New research goes against inflation theory of the big bang

A team of scientists has proposed a powerful new test against inflation, the theory that the universe adequately expanded in size in a fleeting fraction of a second right after the Big Bang. Their goal is to give insight into an interesting question: what was the condition of the universe before the Big Bang actually happened?

Theory:
The predominant cosmological model for the universe which has existed from the initial known phases is the Big Bang theory. Through its subsequent large-scale evolution, the big bang model describes how the universe bolstered from a very high-density and high-temperature state and offers an exhaustive explanation for a broad range of phenomena. This includes the abundance of light elements, the cosmic microwave background (CMB), large scale structure and Hubble’s law.

The Big Bang hypothesis is a push to clarify what occurred at the very beginning of our universe. Albeit there have also been too many misconceptions related to space and time. Revelations in astronomy and physics have appeared past a sensible doubt that our universe indeed has a beginning. The theory is just a way of clarifying what actually happened and what did not.

The primal universe was not entirely uniform. There were tiny irregularities in density on infinitesimal scales that became the seeds of the large-scale structure observed in today’s universe. This is the principal source of information physicists rely on to learn about what happened before the Big Bang.

Avi Loeb of the Center for Astrophysics | Harvard said that “No matter what value people measure for some observable attribute, there are always some models of inflation that can explain it”

Now, a team of scientists led by the CfA’s (Center for Astrophysics) Xingang Chen, along with Loeb, and Zhong-Zhi Xianyu of the Physics Department of Harvard University, have applied an idea they call a “primordial standard clock” to the non-inflationary theories, and laid out a method that may be used to falsify inflation experimentally.

Scientists started their experiment by identifying the defining property of the various theories – the evolution of the size of the primordial universe. Through this, they actually wanted to find some characteristic that can separate inflation from other theories.

Admitting that cosmic inflation is well known for resolving some critical secrets about the structure and advancement of the universe, other altogether different hypotheses can also clarify these issues. In a portion of these hypotheses, the condition of the universe preceding the Big Bang, the purported primordial universe was weak and contracting as opposed to extending, and the Big Bang model theory was in this manner a piece of a Big Bounce.

To identify between inflation and other ideas, the issue of deceit has inevitably arisen. Additionally, some of the scientists have also been so curious about inflation implying that its seemingly endless malleability makes it all but impossible to properly test.

recently observed pentaquark

CERN data unveils three never seen Pentaquarks

Tomasz Skwarnicki, a professor of physics in the College of Arts and Sciences at Syracuse University in New York has discovered data about a new class of pentaquarks. He confirmed the existence of three never seen pentaquarks.

The finding states that the particle, named Pc(4312)+, decays to a proton and a J/ψ particle (composed of a charm quark and an anticharm quark). This latest observation made by him has a statistical significance of 7.3 sigma, passing the threshold of 5 sigma traditionally required to claim a discovery of a new particle.

Skwarnicki is also a part of a team of researchers, including members of Syracuse’s High-Energy Physics (HEP) Group. The research group is religiously involved in studying fundamental particles and forces in the universe. Most of their work takes place at the CERN laboratory in Geneva, whose LHCb is the biggest and evidently the most powerful particle detector in the world. LHCb stands for Large Hadron Collider beauty.

Within the LHC the protons are heaved and flung together at high energies, only to collide with one another. What lies inside the particles, once cracked open, helps scientists probe and enquire into the mysteries of the fundamental universe.

To have a deep understanding of how particles interact and bind together is Skwarnicki’s specialty. In 2015, he and a PhD student Nathan Jurik and a distinguished Professor Sheldon Stone and Liming Zhang, an associate professor at Tsinghua University in Beijing, made headlines with their role in LHCb’s detection of first two pentaquarks. The first two pentaquarks were Pc(4450)+ and Pc(4380)+.

LHCb’s latest data used up an energy beam that was nearly twice as strong. This method when combined with more refined data-selection criteria, produces a greater range of proton collisions.

The data also revealed a third “companion” to it called pentaquark. He adds that “All three pentaquarks had the same pattern similar to that of a baryon with a meson substructure. Their masses were below appropriate for the baryon-meson thresholds”.

Skwarnicki’s discovery occurred relatively fast, considering that LHCb stopped collecting data almost three months ago.

He is excited about the discovery because it helps explain how the smallest constituents of matter behave and change. His latest discovery proves that pentaquarks are built the same way as protons and neutrons, which are bound together in the nucleus of an atom.

Skwarnicki tells that although the pentaquarks don’t play a significant part in the basic matter that humans are made of, their presence and existence will significantly affect the other matter and their models in different parts of the universe such as the neutron stars.

cosine100 dark matter detector

Dark matter mystery intensifies over consistent detection of its signal

Dark matter is one of the Universe’s greatest mysteries. Something is out there generating the gravitational force that can’t be accounted for by detectable matter. The way the stars and galaxies move indicates that up to 85 percent of the matter in the Universe is actually dark matter.

There were many experiments which were carried out in order to understand the dark matter. The researchers are trying hard in order to find out the details about the dark matter as it can answer many unanswered questions about the big bang theory and formation of the universe itself.

The DAMA experiment which was carried out in Italy which included detection of dark matter using the direct detection approach, by using a matrix of NaI(Tl) scintillation detectors to detect dark matter particles in the galactic halo. This experiment has further confirmed the presence of a model-independent annual modulation effect of the data in the 2-6 keV range that satisfy all the features expected for a dark matter signal with high statistical significance.

There are two experiments which are carried out in order to verify the above results. However, ANAIS, a dark matter detector run by the University of Zaragoza at the Canfranc Underground Laboratory in Spain, has delivered results that seem to contradict DAMA‘s.

COSINE-100, run by a collaboration between the Korea Invisible Mass Search and Yale University at the Yangyang Underground Laboratory in South Korea, has now produced new output. These results are similar to what ANAIS’ threw up – but also a little closer to the results DAMA has produced over the last 20 years.

That latest COSINE-100 report also comes after an announcement just a few months ago that the collaboration’s results did not support DAMA’s dark matter findings.

DAMA has been recording WIMP (Weakly interacting massive particles) detections since 1995, observed as an annual fluctuation in the number of light flashes detected.

Because of the orbit of Earth around the Sun, and the Solar System’s orbit around the galactic centre, Earth should theoretically be exposed to dark matter flux from the galactic halo around peaking at around 2 June and ebbing at around 2 December.

This is because the faster we are moving through space, the more dark matter should pound us, and mid-year is when the orbital speeds of Earth and the Solar System combined.

Xenon Dark Matter Detector

A tank filled with liquid xenon deep underground to spot dark matter particles

This is exactly what DAMA scientists claim their results show, but no other dark matter detector has come close to replicating it – not even XENON1T which is hailed as our best shot at finding the elusive stuff.

However, XENON1T uses liquid xenon detectors. Meanwhile, DAMA uses sodium iodide crystal detectors in a tank filled with a liquid scintillator to tag cosmic ray muons. This is what ANAIS and COSINE-100 did, but they still didn’t even get close to DAMA results.

It’s probably going to take a few more years of observations before physicists are any closer to unveiling the truth.

We are truly waiting for the final conclusion which would probably open up some secrets of the universe.

Levitating Object Using Light

Researchers devise a way to levitate objects using only light

During childhood days we have been to the magic shows and we have always wondered as to how the objects over there fly in the air. Now we know that it wasn’t magic, but it was physics applied that made it look like magic.

Now the researchers at the California Institute of Technology claim that they have found a way to levitate and propel objects using light, even though for time being the work remains theoretical. It is believed according to a paper published in Nature Photonics that this technique could be used for trajectory control of ultra-light spacecraft and even laser propelled light sails for space exploration. It means that no fuel needed, just a powerful laser fired at a spacecraft from the earth.

Scientists developed photonic levitation and propulsion system by designing a complex pattern that could be etched into an object’s surface.

The way the concentrated light beam reflected from the etching causes the object to “self-stabilize“, they say, as it attempts to stay inside the focused laser beam.

The groundwork for the new research was the development of optical tweezers and the big downside to it was that it could manipulate tiny objects at the microscopic level only.

Generic Optical Tweezer Diagram

Generic Optical Tweezer Diagram (Credit: Wikimedia)

Ognjen Ilic, post-doctoral scholar and first author of the new study, explains the tweezer concept and its limitations in much simpler terms: “One can levitate a ping pong ball using a steady stream of air from a hairdryer. But it wouldn’t work if the ping pong ball were too big, or if it were too far away from the hair dryer, and so on.

Though the theory is still untested in the real world, the researchers say that if it pans out, it could send a spacecraft to the nearest star outside our Solar System in just 20 years.

There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft,” said Harry Atwater, a professor at the Caltech Division of Engineering and Applied Science.

He also said, “We’re a long way from actually doing that, but we are in the process of testing out the principles.”

Published Research: https://www.nature.com/articles/s41566-019-0373-y