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Is time an illusion?

Time works by measuring periods between the past, present and future. It has a SI base unit, the second,  defined as about 9 billion oscillations of the  cesium  atom. In physics time is needed for  measuring the rate of change, like velocity and acceleration.  In the 17th century, physicist Isaac Newton  based his laws of motion on the assumption that t ime must tick from one second to the next, with no difference between the length of any two seconds. In the other words time is constant scalar universally. This is a valid approximation in daily life but no longer when relativistic effects take place. I n 1905,  Albert Einstein asserted that the speed of light  is instead constant. That cause that time must be relative and depend on the observer.  Einstein concluded that  distinction between past, present, and future is only a stubbornly persistent illusion. In the general relativity time is one dimension coupled to the three space dimensions. As discussed in the blog any energy cont
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Spooky action

In the last blog I mentioned about quantum entanglement. Back in 1927, Niels Bohr and Albert Einstein were debating whether quantum mechanics, however strange, renders the world as it really is. In quantum mechanics a particle’s location, polarization and other properties can be indefinite until the moment they are measured. If a pair of particles is generated such that their total spin is known to be zero, the particles will have opposite spins when they are measured. Furthermore, whatever is the distance between the particles, the measurement of one's spin determines another's. Einstein considered such behavior impossible, as it violated the local realism view of causality, referring to it as "spooky action at a distance". As a conclusion in 1935, Einstein with Boris Podolsky and Nathan Rosen published the famous EPR-paper, which supposedly proved that quantum mechanics could not represent reality. Erwin Schrödinger shortly thereafter published a seminal paper defi
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Into the black hole

As written in my blog , black holes are ultimate sinks in the spacetime, and any information cannot escape beyond the event horizon of the black hole once dropped inside it. I want to open a bit what could be inside a black hole and emphasize that mentioned infinities do not describe the real world. By the "No Hair Theorem" a black hole has only three properties including mass, charge and angular momentum. When a particle drops to a black hole it has impact on these properties. For instance, a mass of the particle adds the mass of the black hole. However, the most of its information gets trapped in the event horizon, such as baryon number or polarization. As written in the previous blog , the event horizon encodes the maximum information density and entropy. The event horizon is a sphere which surface area is proportional to the mass of the black hole squared. If you were to double the mass, the surface area would get four times, and the occupied volume eight times larger. Th
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Living in a hologram

Most of us have watched a holographic photograph that shows 3D image printed on a flat surface. Imagine the whole cosmos being painted on a distant celestial horizon, the three space dimensions we experience are illusion and rather hologram encoded in two dimensions. This sounds crazy but actually there are some clues in the nature that indicates the universe being a hologram. The laws of relativity forbid anything that went inside the event horizon of a black hole from coming out again. In the simplest case, the horizon is a sphere, whose surface area is larger for more massive black holes. If a piece of matter drops inside its energy is added to mass of black hole and energy conservation is upheld. Another fundamental law, the second law of thermodynamics, appears to be violated. This law summarizes the familiar observation that most processes in nature are irreversible: a teacup falls from the table and shatters, but it never gets spontaneously fixed again. In the other words, entro
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Barely new from the dark side

I wrote a  blog  about dark matter that accounts the most of mass of the universe. XENONnT is the latest dark matter detector generation located at the Gran Sasso International Laboratory in Italy. It contains 5.9 tons of liquid xenon waiting  for dark matter particles crashing into xenon atoms’ nuclei, causing them to recoil and emit electons to be detected.  In 2022 July published analysis of 97 days data shows no signs of dark matter particle collisions. This feels a bit disapointment as in 2020, the precessor detector XENON1T found excess of  ricocheting electrons. The cause of the surplus was explained by hypothetical lightweight particles that may originate from the sun called solar axions.  But the excess wasn’t large enough to be convincing, so more data were needed. No reason found for the previous excess but it may have been a statistical fluke.  Similarly, the latest experiments of new generation LZ detector (2022 July) found no dark matter. The detector is 1.5 km undergroun
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Dark balloon

The previous post discussed of dark matter that appears to have gravity effect to hold galaxy clusters together. However, in the larger scale the universe is expanding and galaxy clusters are moving away from us. In 1998, the red shift measurement from the distant galaxies revealed that the rate of expansion is accelerating. According to the general relativity, the matter content of the universe curves all spacetime causing  a global gravitational effect, which would decelerate the expansion. Thus something must counteract and win  the gravitation.   Currently,  dark energy has been the most accepted premise to account for the accelerated expansion and is a part of the standard cosmological lamda-CDM model.  Cosmologists' well-tested standard model assumes that 68% of the content of the universe is dark energy. However, the origin and composition of dark energy is one of the biggest mysteries. The simplest explanation for the dark energy is the cosmological constant,  representing
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A roulette wheel and dark magic

In my blog "On a rubber mat" I briefly described how space-time is determined by its mass energy contents. For instance, a star curves the space around it creating a gravitational pot hole where other matter falls and gets imprisoned. The bigger is the mass the more curvature is resulted. In a galaxy there are billions of starts each contributing to the total curvature of the space around the galaxy. Stars have motion that prevents them to fall in to the center of galaxy.  In the center of a galaxy there is likely always a super massive black hole.  You can think a roulette where you throw multiple balls that start spinning around the center. In contrast to the roulette wheel, there's no friction in the space reducing the speed of the stars, which lets them to orbit the center for ages. If we were able to add more enough speed to a ball while spinning, it would eventually reach the edge of the wheel and rolls out with its current direction. If a star had high enough veloc
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