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math
22 сент., 12:19
Jean-Pierre Serre turns 100.Youngest Fields Medalist ever: 27. First Abel Prize laureate: 2003.and still editing Wikipedia.✅ Follow @math
math
19 сент., 12:17
A whip cracks because a rapidly moving loop travels down its tapered length, transferring energy toward a section with progressively less mass.As the loop approaches the narrow end, its speed rises sharply. Part of the whip can exceed the local speed of sound, creating a shock wave similar to a small sonic boom. The sound comes from compressed air, not from the tip striking anything.High-speed imaging shows that the fastest point may lie within the moving loop rather than at the absolute tip. Its exact motion depends on the whip’s taper, stiffness, and the way it is swung.✅ Follow @math
math
16 сент., 16:36
FUN FACTDuring a lecture Lord Kelvin wrote an integral on the board, turned to the class and asked if they knew what a mathematician is."A mathematician is one to whom that is as obvious as that twice two makes four is to you. Liouville was a mathematician."✅ Follow @math
math
13 сент., 10:35
Kalamsat was the smallest satellite ever launched, which weighed a mere 64 grams and measured 3.8 cm on each side.It was designed by an 18-year-old Indian student named Rifath Sharook and launched on June 22, 2017, through NASA's sounding rocket from Wallops Island.It was named after former Indian President Dr. A. P. J. Abdul Kalam. Its main goal was to test the performance of 3D-printed structures in space and measure space radiation. The total suborbital flight lasted 240 minutes.✅ Follow @math
math
11 сент., 10:35
A black hole is not defined only by darkness. Its mass sets the scale of its horizon, its quantum temperature, and the amount of entropy it can contain.For a non-rotating black hole, radius grows with mass while Hawking temperature falls as mass increases. Larger black holes are therefore colder. Entropy grows with the horizon’s area, connecting gravity, quantum theory, and thermodynamics within a single object.✅ Follow @math
math
9 сент., 10:34
In 1831, Michael Faraday discovered electromagnetic induction by showing that a changing magnetic field could generate an electric current. Joseph Henry independently observed the same phenomenon around the same period.Faraday’s law captures that result mathematically: changing magnetic flux through a coil induces an electromotive force. More coil turns and faster flux changes produce a larger induced voltage.Heinrich Lenz later described the direction of the induced current, showing that it acts to oppose the change that produced it. James Clerk Maxwell eventually incorporated Faraday’s discovery into the equations that unified electricity and magnetism.✅ Follow @math
math
7 сент., 10:35
We know what it does. We still don’t know what it is.Dark energy is one of the biggest mysteries in modern cosmology. The universe is not only expanding, its expansion is accelerating. We call whatever is responsible for this acceleration dark energy, but its true nature remains unknown.Current observations suggest dark energy makes up roughly 68% of the universe’s total energy content. Possible explanations include a cosmological constant, a changing form of energy, or even a modification of gravity.✅ Follow @math
math
5 сент., 10:35
Two pages of Albert Einstein’s 1913 handwritten notes filled with tensor equations, Christoffel symbols, and covariant expressions from his work on gravitation.These notes come from the period when Einstein collaborated with Marcel Grossmann on the Entwurf theory, an early non-Riemannian metric approach that preceded the final 1915 general relativity field equations.✅ Follow @math
math
31 авг., 10:35
Quantum computing replaces the binary logic of classical bits with quantum states. Qubits can exist in superpositions, gates manipulate their amplitudes, and entanglement links their states. Carefully designed interference changes the probability of different outcomes. Measurement then turns the quantum state into classical information.✅ Follow @math
math
29 авг., 10:35
Transformers come in many forms, each built for a different job.Step-up and step-down transformers change voltage, isolation transformers electrically separate circuits, instrument transformers enable safe measurement, while single-phase and three-phase designs serve different power systems. Ferrite and toroidal cores are optimized for different operating conditions, from high-frequency electronics to efficient power conversion.✅ Follow @math
math
27 авг., 10:35
The Bohr model gave us a useful picture of the atom: electrons occupying specific quantized energy levels around the nucleus. But the modern quantum picture is very different. An electron is not a tiny particle following a definite orbit like a planet around the Sun. Its state is described by a wavefunction, and the electron cloud represents the probability distribution for where a measurement may find it.That shift was one of the biggest conceptual changes in physics. Instead of asking “What path does the electron take?”, quantum mechanics asks “What state is the electron in, and what are the probabilities of different measurement outcomes?”The Bohr model still matters because it gets an important piece right: atomic energies are quantized. For hydrogen, its predictions for the energy levels are remarkably accurate. But the full quantum-mechanical description replaces fixed orbits
math
25 авг., 10:34
Srinivasa Ramanujan failed to make it through college, but mathematics was not the problem.In 1904, he entered Government College in Kumbakonam on a scholarship. He became so absorbed in mathematics that he neglected his other subjects. He failed his examinations except mathematics and lost the scholarship.He later tried again at Pachaiyappa’s College in Madras. In the First Arts examination, he passed mathematics but failed all his other subjects.Ramanujan left college without a degree and continued studying mathematics independently.Years later, the same mathematical work brought him to Cambridge and eventually made him a Fellow of the Royal Society.✅ Follow @math
math
23 авг., 10:35
The universe has been changing for 13.8 billion years, from an unimaginably hot early state to the galaxies, stars, planets, and life we see today.This timeline follows some of the biggest transitions along the way:✅ Follow @math
math
21 авг., 10:34
Black surfaces absorb more sunlight because they give fewer wavelengths a way back out. White surfaces do the opposite. The colors we see are simply the wavelengths that escaped.✅ Follow @math
math
19 авг., 10:34
Earth is a lot more dynamic beneath our feet than it looks. It is classified by how the material behaves: rigid lithosphere, slowly flowing asthenosphere, a stronger lower mantle, liquid outer core, and a solid inner core under immense pressure.✅ Follow @math
math
17 авг., 10:34
Every second, Earth is moving around the Sun at nearly 30 km/s, the Solar System is orbiting the Milky Way, and the Milky Way itself is racing through space. We can't feel any of it directly. Yet motion leaves fingerprints in waves, allowing astronomers to measure the speeds of stars, galaxies, and even the expansion history of the universe.The Doppler effect is one of the reasons we can study objects we may never visit.✅ Follow @math
math
14 авг., 10:35
Matter is defined by how its particles cooperate with each other. A diamond, a cloud, lightning, and some of the coldest substances ever created in a laboratory can all emerge from the same underlying ingredients. Change the temperature, energy, or quantum rules, and billions of particles begin behaving in entirely new ways.Near absolute zero the particles can stop acting like individuals altogether. Some merge into a single quantum state, while others pair up and move collectively.✅ Follow @math
math
12 авг., 10:35
A lesson physics students can learn from Einstein.Time seemed obvious until Einstein asked what it meant for two distant events to happen simultaneously. In his 1905 paper on special relativity, he showed that comparing time at different locations requires synchronized clocks, and that observers moving relative to one another do not generally agree on which distant events are simultaneous.For a physics student, the lesson is to examine the physical meaning behind every symbol instead of manipulating equations blindly. For everyone else, it means that familiar ideas are not necessarily well understood. Sometimes progress begins with a question that sounds almost childish.Einstein taught us to question what appears obvious.✅ Follow @math
math
10 авг., 10:34
The word “radiation” covers some very different physical phenomena.An alpha particle is essentially a helium nucleus. Beta radiation consists of electrons or positrons.Gamma rays and X-rays are electromagnetic radiation, while neutrons are uncharged particles.That difference in what they actually are determines how they interact with matter, how far they travel, and what kind of shielding works best.✅ Follow @math
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8 авг., 10:34
The discovery of pulsars in 1967 was so unexpected that their astonishingly regular signals briefly raised the possibility of an artificial origin.Jocelyn Bell Burnell, then a graduate student, noticed the repeating pulses while examining kilometers of chart-recorder paper by hand. The source was eventually identified as a rapidly rotating neutron star, opening an entirely new field of astrophysics and revealing one of the most extreme states of matter known.✅ Follow @math
