Every circle hides the same remarkable constant. Divide a circle's circumference by its diameter and you'll always get π, about 3.14159, no matter the circle's size.
From geometry to astronomy, engineering, and physics, π helps describe the world around us. It's an irrational number, meaning its decimal digits continue forever without repeating.
The Principle of Least Action states that the motion of a physical system is determined by making the action stationary, where the action is defined as the time integral of the Lagrangian, L= KE-PE . Rather than considering a single predetermined route, physics compares all possible paths and the actual motion is the one for which small variations do not change the action to first order.
This elegant idea forms the foundation of classical mechanics and extends to electromagnetism, general relativity, and quantum field theory, making it one of the most fundamental principles in modern physics.
The Poincaré Disc model ✍️
Most of us grow up with flat geometry, where parallel lines never meet and the angles of triangles always add up to exactly 180°. However, space can curve in different ways. In hyperbolic geometry, space bends inward and outward at the same time, like a saddle. The Poincaré disc is a beautiful map of this strange infinite world, contained within a single finite circle.
The green edge represents infinity itself. You can walk toward it forever and never reach it, since the boundary is always infinitely far away. The intricate blue and purple pattern is a perfect tiling: every triangle is truly identical in size and shape, no matter how small it appears near the edge. The graceful curved arcs are actually the straightest possible paths in this geometry; they seem perfectly straight to anyone living inside. Each triangle here has angles that add up to less than 180°. The larger the triangle, the smaller the total becomes. That shrinking angle sum is the clear sign of negative curvature.
When we add time, these discs stack into an hourglass shape called Anti-de Sitter space. Light travels in cone-shaped paths that show the limits of cause and effect. Most remarkably, everything happening with gravity and curved space inside the disc is perfectly mirrored by a quantum theory on its flat boundary. The rich inner world and the simple edge depict exactly the same reality, suggesting that our own universe, with all its dimensions, might ultimately be a type of hologram projected from a lower-dimensional surface. The Poincaré disc isn’t just a pretty picture; it offers insight into how space, time, and reality itself might truly function.
The Bose-Einstein Integral ✍️
Everything in the universe falls into one of two main groups of particles, and the difference between them is crucial for how the universe appears and behaves. Fermions, like electrons and quarks, are antisocial. No two of them can share the same quantum state. This is why matter occupies space and why atoms have structure. Bosons, like photons and other force-carrying particles, are very sociable. They can share the same quantum state and tend to gather there. This behavior explains how lasers work, with countless photons moving in perfect unison, and why Bose-Einstein condensates form when certain atoms are cooled to near absolute zero and suddenly all fall into the same lowest-energy state. The statistical rule that describes how bosons distribute themselves among available energy levels is called the Bose-Einstein distribution. Its most important feature is a denominator made from an exponential function minus one. That crucial minus one represents quantum correction, reflecting boson sociability. This is the same minus one seen in Planck's Law for blackbody radiation, which is no accident because Planck's formula directly relies on this distribution.
The Bose-Einstein integral uses this distribution to sum up boson contributions across all possible energy levels, adjusting each level by how many states are available there. It calculates a total thermodynamic quantity for the entire system. The amazing discovery is what this sum equals: the product of two of the most important functions in mathematics, the Gamma function and the Riemann zeta function. There was no clear reason for them to appear in a calculation about quantum particles. The proof uses a clever trick: we can rewrite the Bose-Einstein distribution factor as an infinite sum of simple exponential terms. This breaks the complicated integral into an infinite series of much simpler ones. Each of these simpler integrals matches the standard form of the Gamma function, which extends the factorial operation to all numbers, not just whole ones. When we add together the leftover coefficients from all these terms, we get one over one to some power, plus one over two to the same power, plus one over three to that power, and so on forever. This defines the Riemann zeta function, the same function whose strange zeros reveal the pattern of prime numbers and whose characteristics form the core of the most famous unsolved problem in mathematics.
The physical implications of this identity are widespread. When the parameter controlling the physical system being calculated equals four, the integral results in a combination involving pi to the fourth power. This is the exact number that appears when you sum Planck's blackbody radiation formula across all frequencies. It leads to the Stefan-Boltzmann law, which states that the total power radiated by a hot object scales as the fourth power of its temperature. This governs everything from the brightness of stars to how infrared cameras work. A different value of the parameter gives the critical temperature at which Bose-Einstein condensation occurs. This links the Nobel Prize-winning 1995 experiment that cooled atoms into a single collective quantum state directly to a special value of the zeta function. The quantized vibrations of atoms in a crystal, which are bosons, give rise to the rule that heat capacity increases as the cube of temperature at low temperatures. What makes this integral so stunning is the hidden unity it reveals. A physicist calculating how much energy a glowing object radiates, a number theorist examining prime numbers, and a mathematician extending factorials are all facing the same underlying mathematical structures. The Bose-Einstein integral is the single formula where the quantum nature of light, the mystery of prime numbers, and the generalization of factorial come together in one elegant identity.
Riemann Sphere ✍️
Mathematicians have long felt uneasy with infinity because you can never truly reach it or handle it well. It stands at the edge of everything, always out of reach. The Riemann sphere addresses this issue elegantly; it turns infinity into the north pole of a sphere. Now, infinity becomes just another point sitting at the top of a ball. It's no longer frightening or unattainable. To see how this works, imagine a sphere resting on a flat table, touching the table at its bottom. Now picture a small light at the top of the sphere shining down. For every point on the flat table around the sphere, you can draw a straight line from the top of the sphere down through its surface to that point on the table. The point where that line intersects the sphere is where that point "lives" on the ball. Points near the center of the table end up near the bottom of the sphere. Points further out on the table end up near the top. And infinity, which had no place on the flat surface, becomes the top point itself the north pole where all the lines converge. This is what the radiating lines in the image represent. The sphere is divided into two colored halves for a reason. The equator separates "small" numbers from "large" numbers. In physics and engineering, this boundary is crucial because it separates stable behavior from unstable behavior in real systems like circuits and signal processors. The blue upper half and red lower half are not just decorations; they convey important information about the nature of the numbers found there. Some of the most powerful actions you can perform on this sphere are surprisingly easy to visualize. Flipping the sphere upside down swaps large numbers with small ones, sending infinity to zero and zero to infinity. Reflecting it across the equator, like flipping a coin, mirrors one type of number into another. These operations might seem like random algebraic tricks on a flat page, but on the sphere, they are natural, intuitive geometric actions things you could do with your hands. The most surprising aspect of the image is how it links this abstract geometry to real physical phenomena. A traveling wave, such as a radio signal or a beam of light moving through space, corresponds to points on the equator of the sphere perfectly balanced, endlessly cycling, always going somewhere. A standing wave, like a vibrating guitar string that oscillates in place without moving, corresponds to a closed loop on the sphere a path that returns to its starting point. Even the behavior of electrons around atoms fits within this framework; electrons can only exist at certain energy levels because their wave patterns must loop seamlessly, and the sphere provides a geometric way to understand why this is true. The quiet message of the whole image is that a radio wave, a guitar string, an electron in an atom, and a filter in your phone are not as different as they might seem. At a fundamental level, they are all just points and paths on the same sphere. The Riemann sphere not only makes infinity manageable; it shows that all these seemingly unrelated phenomena in physics and engineering share one common geometric home.
#خادم_الحرمين_الشريفين بناءً على ما عرضه سمو #ولي_العهد يوجه بالموافقة على استضافة كافة العالقين في مطارات المملكة من الأشقاء الخليجيين مواطني دول مجلس التعاون، وتهيئة كافة الإجراءات لاستضافتهم وإكرامهم، وتهيئة كافة السبل لراحتهم بين أهلهم وأشقائهم في بلدهم الثاني حتى تتهيأ الظروف المناسبة لعودتهم لبلادهم سالمين معززين مكرمين، كما وجه -حفظه الله- كافة الجهات المختصة باتخاذ الإجراءات اللازمة لتنفيذ ذلك في الحال.
#واس
#خادم_الحرمين_الشريفين بناءً على ما عرضه سمو #ولي_العهد يوجه بالموافقة على استضافة كافة العالقين في مطارات المملكة من الأشقاء الخليجيين مواطني دول مجلس التعاون، وتهيئة كافة الإجراءات لاستضافتهم وإكرامهم، وتهيئة كافة السبل لراحتهم بين أهلهم وأشقائهم في بلدهم الثاني حتى تتهيأ الظروف المناسبة لعودتهم لبلادهم سالمين معززين مكرمين، كما وجه -حفظه الله- كافة الجهات المختصة باتخاذ الإجراءات اللازمة لتنفيذ ذلك في الحال.
#بيان | تعرب المملكة العربية السعودية عن رفضها وإدانتها بأشد العبارات للهجمات الإيرانية السافرة والجبانة التي استهدفت منطقة الرياض والمنطقة الشرقية وتم التصدي لها، وهي هجمات لا يمكن تبريرها تحت أي ذريعة و بأي شكل من الأشكال، وقد جاءت على الرغم من عِلم السلطات الإيرانية بأن المملكة أكدت أنها لن تسمح باستخدام أجوائها وأراضيها لاستهداف إيران.
11 Python Books for FREE...
1. Think Python (O'Reilly)
https://t.co/GYR8phbCmG
2. The Big Book of Small Python Projects
https://t.co/bNzMWFFBht
3. Data Structures
https://t.co/MclmxwHkLI
4. Data Science Handbook
https://t.co/YUhHr1DJsx
5. Data Analysis
https://t.co/XTAev8gayn
6. Data Science
https://t.co/SRTb74kcvP
7. Machine learning
https://t.co/E6D8R5HCVp
8. Statistics
https://t.co/sjgJvZiK5m
9. Think Bayes
https://t.co/pmNDkVVCyv
10. Clean Code in Python (Packt)
https://t.co/37UxgEfHbl
11. Learn More Python 3 The Hard Way
https://t.co/DnrBtxujVV
بخصوص #بنزين_98 النصيحة بالمختصر كالتالي :
التزم بالموجود في كتالوج سيارتك .
ودائما رفع الأوكتان لا يضر ولكنه قد لا يكون مفيد والعكس صحيح
يعني لو سيارتك تقبل ٩١ تقدر تعبي ٩٥ ولو ٩٥ تقدر تعبي ٩٨ ولكن العكس مضر
لو سيارتك مطلوب لها ٩٥ لا تعبي ٩١
وتفاصيل أكثر موجودة في الفيديو