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Bertrand’s Theorem states that only two central forces close every bounded orbit: F(r) ∝ - 1/r² and F(r) ∝ - r. The first gives the familiar Keplerian ellipses of Newtonian gravity. The second is the isotropic harmonic oscillator. Other central forces can still conserve energy and angular momentum, but... show more

Mathelirium

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17,147 views • 28 days ago •via X (Twitter)

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A Triple Spring-Mass Pendulum Just for The Fun of Physics We model the mass positions as r₁ = (x₁, y₁), r₂ = (x₂, y₂), r₃ = (x₃, y₃) with y positive downward in the simulation. The three spring segments are r₁ = r₁ − (0,0) r₁₂ = r₂ − r₁ r₂₃ = r₃ − r₂ Each spring applies a Hooke force along its own direction, F(r; k, L) = −k (|r| − L) (r / |r|) and each mass also feels gravity, Fgᵢ = (0, mᵢ g) So the equations of motion are m₁ r̈₁ = Fg₁ + F(r₁; k₁, L₁) − F(r₁₂; k₂, L₂) m₂ r̈₂ = Fg₂ + F(r₁₂; k₂, L₂) − F(r₂₃; k₃, L₃) m₃ r̈₃ = Fg₃ + F(r₂₃; k₃, L₃) We integrate these ODEs forward with RK4 using a small dt. Different scenes come from changing the mass ratios and from giving the third mass a small initial kick. The yellow trail is the path of the third mass. The inset phase portraits show the same motion in state space: (x₃, vₓ₃) and (−y₃, vᵧ₃) When those curves stay tight and loop cleanly, the motion is more regular. When they spread, fold, and smear, energy is being redistributed across the whole chain between gravity, spring stretch, and kinetic motion. #NonlinearDynamics #CoupledOscillators #SpringPendulum #ChaosInMotion #ComputationalPhysics #MathematicalVisualization

A Triple Spring-Mass Pendulum Just for The Fun of Physics We model the mass positions as r₁ = (x₁, y₁), r₂ = (x₂, y₂), r₃ = (x₃, y₃) with y positive downward in the simulation. The three spring segments are r₁ = r₁ − (0,0) r₁₂ = r₂ − r₁ r₂₃ = r₃ − r₂ Each spring applies a Hooke force along its own direction, F(r; k, L) = −k (|r| − L) (r / |r|) and each mass also feels gravity, Fgᵢ = (0, mᵢ g) So the equations of motion are m₁ r̈₁ = Fg₁ + F(r₁; k₁, L₁) − F(r₁₂; k₂, L₂) m₂ r̈₂ = Fg₂ + F(r₁₂; k₂, L₂) − F(r₂₃; k₃, L₃) m₃ r̈₃ = Fg₃ + F(r₂₃; k₃, L₃) We integrate these ODEs forward with RK4 using a small dt. Different scenes come from changing the mass ratios and from giving the third mass a small initial kick. The yellow trail is the path of the third mass. The inset phase portraits show the same motion in state space: (x₃, vₓ₃) and (−y₃, vᵧ₃) When those curves stay tight and loop cleanly, the motion is more regular. When they spread, fold, and smear, energy is being redistributed across the whole chain between gravity, spring stretch, and kinetic motion. #NonlinearDynamics #CoupledOscillators #SpringPendulum #ChaosInMotion #ComputationalPhysics #MathematicalVisualization

Mathelirium

36,155 views • 5 months ago

What If a Black Hole Shredded Worlds Before They Fell In? Far away from a Black Hole, an object can orbit, drift past, or escape. But if its path carries it too close, the geometry decides its fate. The exterior geometry is Schwarzschild-like ds² = -(1 - 2M/r)dt² + (1 - 2M/r)⁻¹dr² + r²dΩ² The event horizon sits at rₛ = 2M The photon sphere sits at rₚₕ = 3M #Astrophysics #GeneralRelativity #Einstein #BlackHole #Spacetime #TidalForces #PhotonSphere #Cosmology #Mathematics

What If a Black Hole Shredded Worlds Before They Fell In? Far away from a Black Hole, an object can orbit, drift past, or escape. But if its path carries it too close, the geometry decides its fate. The exterior geometry is Schwarzschild-like ds² = -(1 - 2M/r)dt² + (1 - 2M/r)⁻¹dr² + r²dΩ² The event horizon sits at rₛ = 2M The photon sphere sits at rₚₕ = 3M #Astrophysics #GeneralRelativity #Einstein #BlackHole #Spacetime #TidalForces #PhotonSphere #Cosmology #Mathematics

Mathelirium

40,811 views • 1 month ago

This is a living map of a complex rational field: cool regions are root-dominant (|R| 1), where R is the complex rational function. Phase stripes come from arg S (the logarithmic derivative of our complex field R) and particles surf the Newton flow. 🤩🤗😍

This is a living map of a complex rational field: cool regions are root-dominant (|R| 1), where R is the complex rational function. Phase stripes come from arg S (the logarithmic derivative of our complex field R) and particles surf the Newton flow. 🤩🤗😍

Mathelirium

29,237 views • 10 months ago

White Hole - A Black Hole With Time Reversed A White Hole is the time-reversed shadow of a Black Hole. It appears in the maximally extended Schwarzschild solution of General Relativity. The exterior geometry is the same ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² The difference is causal. A Black Hole lets paths enter but not escape. A White Hole lets paths emerge but not enter. No White Hole has been observed. But inside the equations of GR, the question is real: What does a Black Hole look like when time runs the other way?

White Hole - A Black Hole With Time Reversed A White Hole is the time-reversed shadow of a Black Hole. It appears in the maximally extended Schwarzschild solution of General Relativity. The exterior geometry is the same ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² The difference is causal. A Black Hole lets paths enter but not escape. A White Hole lets paths emerge but not enter. No White Hole has been observed. But inside the equations of GR, the question is real: What does a Black Hole look like when time runs the other way?

Mathelirium

74,866 views • 3 months ago

Physics feels stable, predictable, and well-behaved largely because we learned it in 3D. That comfort hides a trap. In 1907, Paul Ehrenfest pointed out something unsettling. If you take the laws we treat as fundamental and transplant them into a different number of spatial dimensions, they often stop working the way we expect. Not just numerically different but qualitatively different. The issue isn’t the force law by itself. It’s geometry. Gauss’s law ties inverse-square forces to the surface area of spheres, and sphere geometry depends on dimension. Change the dimension, and the same-looking force produces a different potential, a different balance of attraction and inertia, and a different fate for motion. You can see this cleanly with a single problem of central force motion. In d spatial dimensions, flux conservation gives F(r) ∝ 1 / rᵈ⁻¹ so the potential scales as V(r) ∝ −1 / rᵈ⁻² (for d ≠ 2) Now add angular momentum. The effective radial potential becomes V_eff(r) = L² / (2 m r²) − C / rᵈ⁻² In 3D, those two terms balance in just the right way to allow stable bound orbits. Small perturbations stay small. Atoms don’t collapse. Planets don’t spiral away. In other dimensions, that balance breaks. In 2D, the force becomes 1/r, the potential becomes logarithmic, and bound motion sits on a knife edge. In 4D and higher, the attractive term becomes too steep. The centrifugal barrier loses the fight. Orbits plunge or escape. Same equations. Same initial conditions. Different dimension. Different physics. This isn’t science fiction. It’s a warning label. So it's clear that a lot of what we call physical intuition is really three-dimensional intuition wearing a lab coat. #Physics #MathematicalPhysics #ClassicalMechanics #DynamicalSystems #Geometry #Ehrenfest

Physics feels stable, predictable, and well-behaved largely because we learned it in 3D. That comfort hides a trap. In 1907, Paul Ehrenfest pointed out something unsettling. If you take the laws we treat as fundamental and transplant them into a different number of spatial dimensions, they often stop working the way we expect. Not just numerically different but qualitatively different. The issue isn’t the force law by itself. It’s geometry. Gauss’s law ties inverse-square forces to the surface area of spheres, and sphere geometry depends on dimension. Change the dimension, and the same-looking force produces a different potential, a different balance of attraction and inertia, and a different fate for motion. You can see this cleanly with a single problem of central force motion. In d spatial dimensions, flux conservation gives F(r) ∝ 1 / rᵈ⁻¹ so the potential scales as V(r) ∝ −1 / rᵈ⁻² (for d ≠ 2) Now add angular momentum. The effective radial potential becomes V_eff(r) = L² / (2 m r²) − C / rᵈ⁻² In 3D, those two terms balance in just the right way to allow stable bound orbits. Small perturbations stay small. Atoms don’t collapse. Planets don’t spiral away. In other dimensions, that balance breaks. In 2D, the force becomes 1/r, the potential becomes logarithmic, and bound motion sits on a knife edge. In 4D and higher, the attractive term becomes too steep. The centrifugal barrier loses the fight. Orbits plunge or escape. Same equations. Same initial conditions. Different dimension. Different physics. This isn’t science fiction. It’s a warning label. So it's clear that a lot of what we call physical intuition is really three-dimensional intuition wearing a lab coat. #Physics #MathematicalPhysics #ClassicalMechanics #DynamicalSystems #Geometry #Ehrenfest

Mathelirium

32,138 views • 6 months ago

Quantum Mechanics Series Lecture 4 Lecture 1 established that ρ(x,t) = |ψ(x,t)|² behaves like a conserved probability density. Lecture 2 showed what drives that flow. We also saw that writing ψ = r exp(iθ) makes the probability current proportional to the phase gradient, making it clear that phase geometry literally steers the motion. Lecture 3 then showed that the centroid of that flow can move almost classically when the packet is tight and the external potential is smooth. However, that raises yet another question. If the centroid can look classical, why does the full wave still spread, bend, split, and interfere in ways no classical particle cloud would? This is because the wave is not driven only by the external potential. It is also driven by its own curvature. Write ψ(x,t) = r(x,t) exp(iθ(x,t)) with ρ = r². Then Schrödinger’s equation gives two coupled real equations. One is the continuity equation you already know. The other looks like a Hamilton-Jacobi equation, but with one extra term: Q = −(1/2m) ∇²r / r This is the so-called Quantum Potential. It depends entirely on how the amplitude bends across space. So, the wave is being shaped not only by V(x,t), but also by the geometry of its own envelope. In the animation, the upper surface is still |ψ| and its skin is still colored by arg(ψ). The glowing threads still trace the probability current. But now a second membrane hangs underneath. That lower membrane encodes the quantum potential Q itself. The porcelain bead marks the quantum centroid. The amber bead follows a classical centroid under the same external V. When those paths separate, the lower membrane tells you why. The difference is not magic but the extra term classical mechanics does not have. The math breakdown: Start from Schrödinger evolution in units with ħ = 1: i ∂ψ/∂t = [ −(1/2m) ∇² + V(x,t) ] ψ Write the state in polar form: ψ = r exp(iθ) Then ρ = |ψ|² = r² From the imaginary part, you recover probability conservation: ∂ρ/∂t + ∇·j = 0 with j = (1/m) Im(ψ* ∇ψ) = (ρ/m) ∇θ So the local velocity field is v = j / ρ = ∇θ / m Now take the real part of Schrödinger’s equation. That gives ∂θ/∂t + |∇θ|² / (2m) + V + Q = 0 where Q = −(1/2m) ∇²r / r This is the classical Hamilton-Jacobi equation with one extra term. That extra term is what makes quantum motion locally different from classical motion. Take a gradient of that phase equation and use v = ∇θ / m. Then the flow obeys an Euler-like equation: ∂v/∂t + (v·∇)v = −(1/m) ∇(V + Q) In other words, there are really two forces in the problem. One comes from the external potential V. The other comes from the wave’s own curvature through Q. That is why Ehrenfest is only approximate. The centroid can still satisfy d⟨x⟩/dt = ⟨p⟩/m d⟨p⟩/dt = −⟨∇V⟩ but the internal shape of the packet evolves under the combined influence of V and Q. When the packet stays broad and smooth, Q is gentle and the motion looks more classical. When the packet develops sharp curvature or interference structure, Q becomes strong and the classical picture breaks down. That is what this scene is designed to show live. #QuantumMechanics #Wavefunction #SchrodingerEquation #BornRule #ProbabilityCurrent #ContinuityEquation #Phase #EhrenfestTheorem #QuantumPotential #Madelung #HamiltonJacobi #MathematicalPhysics #Mathematics #Physics

Quantum Mechanics Series Lecture 4 Lecture 1 established that ρ(x,t) = |ψ(x,t)|² behaves like a conserved probability density. Lecture 2 showed what drives that flow. We also saw that writing ψ = r exp(iθ) makes the probability current proportional to the phase gradient, making it clear that phase geometry literally steers the motion. Lecture 3 then showed that the centroid of that flow can move almost classically when the packet is tight and the external potential is smooth. However, that raises yet another question. If the centroid can look classical, why does the full wave still spread, bend, split, and interfere in ways no classical particle cloud would? This is because the wave is not driven only by the external potential. It is also driven by its own curvature. Write ψ(x,t) = r(x,t) exp(iθ(x,t)) with ρ = r². Then Schrödinger’s equation gives two coupled real equations. One is the continuity equation you already know. The other looks like a Hamilton-Jacobi equation, but with one extra term: Q = −(1/2m) ∇²r / r This is the so-called Quantum Potential. It depends entirely on how the amplitude bends across space. So, the wave is being shaped not only by V(x,t), but also by the geometry of its own envelope. In the animation, the upper surface is still |ψ| and its skin is still colored by arg(ψ). The glowing threads still trace the probability current. But now a second membrane hangs underneath. That lower membrane encodes the quantum potential Q itself. The porcelain bead marks the quantum centroid. The amber bead follows a classical centroid under the same external V. When those paths separate, the lower membrane tells you why. The difference is not magic but the extra term classical mechanics does not have. The math breakdown: Start from Schrödinger evolution in units with ħ = 1: i ∂ψ/∂t = [ −(1/2m) ∇² + V(x,t) ] ψ Write the state in polar form: ψ = r exp(iθ) Then ρ = |ψ|² = r² From the imaginary part, you recover probability conservation: ∂ρ/∂t + ∇·j = 0 with j = (1/m) Im(ψ* ∇ψ) = (ρ/m) ∇θ So the local velocity field is v = j / ρ = ∇θ / m Now take the real part of Schrödinger’s equation. That gives ∂θ/∂t + |∇θ|² / (2m) + V + Q = 0 where Q = −(1/2m) ∇²r / r This is the classical Hamilton-Jacobi equation with one extra term. That extra term is what makes quantum motion locally different from classical motion. Take a gradient of that phase equation and use v = ∇θ / m. Then the flow obeys an Euler-like equation: ∂v/∂t + (v·∇)v = −(1/m) ∇(V + Q) In other words, there are really two forces in the problem. One comes from the external potential V. The other comes from the wave’s own curvature through Q. That is why Ehrenfest is only approximate. The centroid can still satisfy d⟨x⟩/dt = ⟨p⟩/m d⟨p⟩/dt = −⟨∇V⟩ but the internal shape of the packet evolves under the combined influence of V and Q. When the packet stays broad and smooth, Q is gentle and the motion looks more classical. When the packet develops sharp curvature or interference structure, Q becomes strong and the classical picture breaks down. That is what this scene is designed to show live. #QuantumMechanics #Wavefunction #SchrodingerEquation #BornRule #ProbabilityCurrent #ContinuityEquation #Phase #EhrenfestTheorem #QuantumPotential #Madelung #HamiltonJacobi #MathematicalPhysics #Mathematics #Physics

Mathelirium

20,456 views • 4 months ago

Quantum mechanics has a reputation for being mystical mainly because people skip the rules and jump to interpretations. In this lecture series, we’re doing the opposite. We start from the rules, follow the algebra, and let the picture be the calculation. Classical Probability Theory combines alternatives by adding their probabilities. Quantum Theory combines them one step earlier…add complex amplitudes first, then square at the end. That swap in order is everything. Expand |a₁ + a₂|² and you don’t just get |a₁|² + |a₂|²…you get a cross-term, 2 Re(a₁ a₂*). Its sign is set by phase, so the same two contributions can reinforce or cancel. Interference is just the algebra of squaring a sum. In the 3D render, the surface height is proportional to |a(x)| (so peaks become bright bands after squaring), while the surface skin is colored by the local phase arg(a(x)). As the phase knob φ(t) is swept on path 2, the cross-term oscillates, and you literally watch the interference ridges slide across the screen. We model a detector screen with coordinates x in R² (think x = (x,y)). A quantum state assigns a complex amplitude a(x). The rule for outcomes is p(x) = |a(x)|² Now the key situation: two coherent alternatives contribute to the same outcome x. Let their amplitudes be a₁(x) and a₂(x). Quantum says a(x) = a₁(x) + a₂(x) So the probability density becomes p(x) = |a₁(x) + a₂(x)|² Expand it (this is the whole episode): p(x) = (a₁ + a₂)(a₁* + a₂*) = |a₁|² + |a₂|² + a₁ a₂* + a₁* a₂ = |a₁|² + |a₂|² + 2 Re(a₁ a₂*) That last term is the interference term. It can be positive or negative. To see phase explicitly, write each contribution in polar form: a₁(x) = r₁(x) exp(i θ₁(x)) a₂(x) = r₂(x) exp(i θ₂(x)) Then a₁ a₂* = r₁ r₂ exp(i(θ₁ − θ₂)) So the cross-term is 2 Re(a₁ a₂*) = 2 r₁ r₂ cos(θ₁(x) − θ₂(x)) That’s the fringe engine: p(x) = r₁² + r₂² + 2 r₁ r₂ cos(Δθ(x)) Now the phase knob we animate: Add a controllable phase shift φ to path 2: a₂(x) → a₂(x) exp(i φ) Then Δθ(x) → Δθ(x) − φ, so p(x; φ) = r₁² + r₂² + 2 r₁ r₂ cos(Δθ(x) − φ) As φ changes smoothly, the bright/dark pattern slides continuously. Same setup, same geometry, same magnitudes r₁,r₂, only phase changed. #QuantumMechanics #WaveInterference #ComplexAmplitudes #DoubleSlit #Physics #Mathematics

Quantum mechanics has a reputation for being mystical mainly because people skip the rules and jump to interpretations. In this lecture series, we’re doing the opposite. We start from the rules, follow the algebra, and let the picture be the calculation. Classical Probability Theory combines alternatives by adding their probabilities. Quantum Theory combines them one step earlier…add complex amplitudes first, then square at the end. That swap in order is everything. Expand |a₁ + a₂|² and you don’t just get |a₁|² + |a₂|²…you get a cross-term, 2 Re(a₁ a₂). Its sign is set by phase, so the same two contributions can reinforce or cancel. Interference is just the algebra of squaring a sum. In the 3D render, the surface height is proportional to |a(x)| (so peaks become bright bands after squaring), while the surface skin is colored by the local phase arg(a(x)). As the phase knob φ(t) is swept on path 2, the cross-term oscillates, and you literally watch the interference ridges slide across the screen. We model a detector screen with coordinates x in R² (think x = (x,y)). A quantum state assigns a complex amplitude a(x). The rule for outcomes is p(x) = |a(x)|² Now the key situation: two coherent alternatives contribute to the same outcome x. Let their amplitudes be a₁(x) and a₂(x). Quantum says a(x) = a₁(x) + a₂(x) So the probability density becomes p(x) = |a₁(x) + a₂(x)|² Expand it (this is the whole episode): p(x) = (a₁ + a₂)(a₁ + a₂) = |a₁|² + |a₂|² + a₁ a₂ + a₁* a₂ = |a₁|² + |a₂|² + 2 Re(a₁ a₂) That last term is the interference term. It can be positive or negative. To see phase explicitly, write each contribution in polar form: a₁(x) = r₁(x) exp(i θ₁(x)) a₂(x) = r₂(x) exp(i θ₂(x)) Then a₁ a₂ = r₁ r₂ exp(i(θ₁ − θ₂)) So the cross-term is 2 Re(a₁ a₂*) = 2 r₁ r₂ cos(θ₁(x) − θ₂(x)) That’s the fringe engine: p(x) = r₁² + r₂² + 2 r₁ r₂ cos(Δθ(x)) Now the phase knob we animate: Add a controllable phase shift φ to path 2: a₂(x) → a₂(x) exp(i φ) Then Δθ(x) → Δθ(x) − φ, so p(x; φ) = r₁² + r₂² + 2 r₁ r₂ cos(Δθ(x) − φ) As φ changes smoothly, the bright/dark pattern slides continuously. Same setup, same geometry, same magnitudes r₁,r₂, only phase changed. #QuantumMechanics #WaveInterference #ComplexAmplitudes #DoubleSlit #Physics #Mathematics

Mathelirium

81,501 views • 7 months ago

Elon Musk on how Starship turns mass to orbit from thousands of tons into millions SpaceX already delivers almost 90% of all Earth mass to orbit with Falcon 9 and Falcon Heavy Most of the remaining mass comes from China, while the rest of the world, including the rest of the US, makes up only about 5% to 7% But Starship takes this to a completely different level Today, SpaceX is around 2,500 tonnes per year to orbit With Starship, the goal is millions of tonnes per year to orbit And SpaceX can reach 1 million tonnes to orbit per year in about three years That is not a small upgrade That is many orders of magnitude more mass to orbit than what exists today Falcon made SpaceX the dominant launch provider Starship turns orbit into industrial infrastructure

Elon Musk on how Starship turns mass to orbit from thousands of tons into millions SpaceX already delivers almost 90% of all Earth mass to orbit with Falcon 9 and Falcon Heavy Most of the remaining mass comes from China, while the rest of the world, including the rest of the US, makes up only about 5% to 7% But Starship takes this to a completely different level Today, SpaceX is around 2,500 tonnes per year to orbit With Starship, the goal is millions of tonnes per year to orbit And SpaceX can reach 1 million tonnes to orbit per year in about three years That is not a small upgrade That is many orders of magnitude more mass to orbit than what exists today Falcon made SpaceX the dominant launch provider Starship turns orbit into industrial infrastructure

X Freeze

13,614 views • 2 months ago

Gravity makes things orbit...but what happens when the mass distribution itself is rotating and dragging phase space into resonances and chaos? In this scene we follow tens of thousands of stars in a toy barred galaxy: a flat disc with a central mass and a rotating bar of extra density that is not rigid, but wobbling, swaying, and breathing in strength over time. The stars start on almost circular orbits in a calm ring, but as the bar turns and its pattern speed and strength modulate, they feel a time-dependent gravitational shove that nudges some onto resonant tracks. 🤩😍 #Mathelirium #Astrophysics #GalacticDynamics #BarredGalaxy #PhaseSpace #HamiltonianChaos #OrbitalResonance

Gravity makes things orbit...but what happens when the mass distribution itself is rotating and dragging phase space into resonances and chaos? In this scene we follow tens of thousands of stars in a toy barred galaxy: a flat disc with a central mass and a rotating bar of extra density that is not rigid, but wobbling, swaying, and breathing in strength over time. The stars start on almost circular orbits in a calm ring, but as the bar turns and its pattern speed and strength modulate, they feel a time-dependent gravitational shove that nudges some onto resonant tracks. 🤩😍 #Mathelirium #Astrophysics #GalacticDynamics #BarredGalaxy #PhaseSpace #HamiltonianChaos #OrbitalResonance

Mathelirium

152,143 views • 8 months ago

White Holes Don’t Push You Way. Spacetime Refuses Your Future. A White Hole appears in the maximally extended Schwarzschild solution of General Relativity, the full mathematical extension of the Spacetime around an eternal, non-rotating Black Hole. The exterior geometry is the same Schwarzschild geometry ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² But the causal direction is reversed. For a Black Hole, future-directed paths can cross the horizon inward. For a White Hole, future-directed paths can emerge from the horizon, but outside particles cannot enter that region. The object has not been observed in nature. But inside the Mathematics of General Relativity, it is a real sector of the extended Schwarzschild Spacetime... the Black Hole’s time-reversed counterpart.

White Holes Don’t Push You Way. Spacetime Refuses Your Future. A White Hole appears in the maximally extended Schwarzschild solution of General Relativity, the full mathematical extension of the Spacetime around an eternal, non-rotating Black Hole. The exterior geometry is the same Schwarzschild geometry ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² But the causal direction is reversed. For a Black Hole, future-directed paths can cross the horizon inward. For a White Hole, future-directed paths can emerge from the horizon, but outside particles cannot enter that region. The object has not been observed in nature. But inside the Mathematics of General Relativity, it is a real sector of the extended Schwarzschild Spacetime... the Black Hole’s time-reversed counterpart.

Mathelirium

31,120 views • 3 months ago

General Relativity allows a geometry where two distant regions of Spacetime become connected through a curved throat. In 1935, Albert Einstein and Nathan Rosen showed that the Schwarzschild solution can be extended into a bridge-like structure. The metric is ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² Under maximal coordinate extension, the Spacetime splits into two asymptotically flat regions joined through a narrow throat called, the Einstein–Rosen bridge. It's a geometric structure emerging directly from Einstein’s field equations. #EinsteinRosenBridge #GeneralRelativity #SpacetimeGeometry #BlackHolePhysics #EinsteinFieldEquations #Relativity

General Relativity allows a geometry where two distant regions of Spacetime become connected through a curved throat. In 1935, Albert Einstein and Nathan Rosen showed that the Schwarzschild solution can be extended into a bridge-like structure. The metric is ds² = −(1 − 2M/r)dt² + (1 − 2M/r)⁻¹dr² + r²dΩ² Under maximal coordinate extension, the Spacetime splits into two asymptotically flat regions joined through a narrow throat called, the Einstein–Rosen bridge. It's a geometric structure emerging directly from Einstein’s field equations. #EinsteinRosenBridge #GeneralRelativity #SpacetimeGeometry #BlackHolePhysics #EinsteinFieldEquations #Relativity

Mathelirium

26,356 views • 2 months ago

Thank you for taking the time to write this up — and for the pointer to your thesis; that figure is beautiful. You're right that classical sphere inversion is exactly the starting point: the feature is named "Sphere Inversion" in the tool for that reason. "Inversphere" is the name of the resulting object, not a claim of new mathematics. I should say up front that I'm not a mathematician, so please correct me if I get any of this wrong. My motivation was visual rather than mathematical: with the classical map, the entire far field piles up into a dense blob at the center (10× farther ⇒ 10× closer), and I simply wanted to control that density to balance the look of the finished object. To do that, the radial profile is generalized to f(r) = R·h(v), where v = (R/r − R/D)/(1 − R/D) is a normalized inverted depth and h is a μ-law log compression, h(v) = ln(1+μv)/ln(1+μ). Classical R²/r is the special case μ = 0, D = ∞. The footage here uses μ > 0, so — as far as I can tell — the map shown is outside the conformal family: the tangential scale f/r and radial scale |f′| agree only in the classical limit. If I understand Liouville's theorem correctly, this trade-off was unavoidable: staying conformal in 3D leaves no freedom to adjust the density, so angle preservation is given up deliberately in exchange for control over it. With μ > 0, mid-field depth below the sphere surface grows like log r, so distant scenery layers logarithmically inside the sphere. The 3DGS side also needed some care: each splat's covariance is carried by the Jacobian J = s·I + (f′−s)nnᵀ, depth sorting has to be re-keyed because inversion reverses the radial order, and the on/off transition is a linear blend whose Jacobian is exactly mix(I, J, t). Thanks again for taking the time — an expert eye on this is very welcome.

VoxelKei

30,621 views • 29 days ago

A White Hole is a Black Hole Running Backward A Black Hole is famous because it lets things fall in, but never lets them come back out. A White Hole is the time-reversed version of that idea. In the full Schwarzschild solution of General Relativity, the Black-Hole region and the White-Hole region appear as two different causal parts of the same exact geometry. Outside the horizon, the metric is the usual Schwarzschild metric ds² = -(1 - 2M/r)dt² + (1 - 2M/r)⁻¹dr² + r²dΩ². The horizon sits at rₛ = 2M, using G = c = 1. For an ordinary Black Hope, future-directed paths can cross this surface inward. Once they do, they cannot return to the outside universe. For a White Hole, the arrow is reversed and particles and light can come out from the horizon, but outside observers cannot enter it. No one has observed a physical White Hole. It may be an ideal solution rather than an object that nature actually forms. But as Mathematics, it is one of the strangest lessons of General Relativity: The equations allow a horizon that throws the universe outward. #WhiteHoles #GeneralRelativity #Schwarzschild #Spacetime #BlackHoles #Cosmology #Physics #Mathematics #Astrophysics #Astronomy

A White Hole is a Black Hole Running Backward A Black Hole is famous because it lets things fall in, but never lets them come back out. A White Hole is the time-reversed version of that idea. In the full Schwarzschild solution of General Relativity, the Black-Hole region and the White-Hole region appear as two different causal parts of the same exact geometry. Outside the horizon, the metric is the usual Schwarzschild metric ds² = -(1 - 2M/r)dt² + (1 - 2M/r)⁻¹dr² + r²dΩ². The horizon sits at rₛ = 2M, using G = c = 1. For an ordinary Black Hope, future-directed paths can cross this surface inward. Once they do, they cannot return to the outside universe. For a White Hole, the arrow is reversed and particles and light can come out from the horizon, but outside observers cannot enter it. No one has observed a physical White Hole. It may be an ideal solution rather than an object that nature actually forms. But as Mathematics, it is one of the strangest lessons of General Relativity: The equations allow a horizon that throws the universe outward. #WhiteHoles #GeneralRelativity #Schwarzschild #Spacetime #BlackHoles #Cosmology #Physics #Mathematics #Astrophysics #Astronomy

Mathelirium

44,259 views • 1 month ago

Do you actually know what convex optimization is in the geometric, guarantee-theoretic sense or have you only met it through solvers and loss curves? Convexity is rare comfort in optimization...there are no spurious local minima, no surprise traps, and inequalities you can use like tools instead of prayers. So, what is this convexity? Let x = (x₁, x₂) and let f(x) be convex. Plot the surface z = f(x). Pick a contact point x₀. The local slope is the gradient p = ∇f(x₀). That p is exactly the data that defines the supporting plane: z = f(x₀) + p · (x − x₀). Thus, f is said to be convex because for every x, f(x) ≥ f(x₀) + p · (x − x₀). So the plane at x₀ can slide under the surface, but it never slices through it. Not near the point...everywhere. Now for here is the interesting part: The slope becomes a coordinate system! Rewrite the same plane as z = p · x − b, where b is the offset. Because the plane passes through (x₀, f(x₀)), the offset is forced to be b = p · x₀ − f(x₀). And that number isn’t just geometry trivia. It’s the convex conjugate: f*(p) = sup over x ( p · x − f(x) ). At a differentiable contact point, the supporting plane touches f tightly enough that the supremum is achieved at x₀, giving the identity f*(p) = p · x₀ − f(x₀) when p = ∇f(x₀). So one moving contact point gives two linked readouts: primal position x₀ dual position (slope) p = ∇f(x₀) dual offset f*(p) One surface. Two worlds. #ConvexOptimization #Optimization #MachineLearning #SignalProcessing #AppliedMath #Engineering

Do you actually know what convex optimization is in the geometric, guarantee-theoretic sense or have you only met it through solvers and loss curves? Convexity is rare comfort in optimization...there are no spurious local minima, no surprise traps, and inequalities you can use like tools instead of prayers. So, what is this convexity? Let x = (x₁, x₂) and let f(x) be convex. Plot the surface z = f(x). Pick a contact point x₀. The local slope is the gradient p = ∇f(x₀). That p is exactly the data that defines the supporting plane: z = f(x₀) + p · (x − x₀). Thus, f is said to be convex because for every x, f(x) ≥ f(x₀) + p · (x − x₀). So the plane at x₀ can slide under the surface, but it never slices through it. Not near the point...everywhere. Now for here is the interesting part: The slope becomes a coordinate system! Rewrite the same plane as z = p · x − b, where b is the offset. Because the plane passes through (x₀, f(x₀)), the offset is forced to be b = p · x₀ − f(x₀). And that number isn’t just geometry trivia. It’s the convex conjugate: f(p) = sup over x ( p · x − f(x) ). At a differentiable contact point, the supporting plane touches f tightly enough that the supremum is achieved at x₀, giving the identity f(p) = p · x₀ − f(x₀) when p = ∇f(x₀). So one moving contact point gives two linked readouts: primal position x₀ dual position (slope) p = ∇f(x₀) dual offset f*(p) One surface. Two worlds. #ConvexOptimization #Optimization #MachineLearning #SignalProcessing #AppliedMath #Engineering

Mathelirium

38,506 views • 7 months ago

Lanterns on the Logarithmic Sea Zeros and poles of a complex rational function R(z,t) drift across a 3D landscape carved from the logarithmic potential U(z,t)=log|R(z,t)|. Every ridge, valley, and glowing thread comes from the moving R(z,t), while the particles follow the tangent field of its level curves. The golden lantern ovals mark the singularities directly. So, the whole scene becomes a living map of where the function vanishes, where it blows up, and how the surrounding geometry bends in response.

Lanterns on the Logarithmic Sea Zeros and poles of a complex rational function R(z,t) drift across a 3D landscape carved from the logarithmic potential U(z,t)=log|R(z,t)|. Every ridge, valley, and glowing thread comes from the moving R(z,t), while the particles follow the tangent field of its level curves. The golden lantern ovals mark the singularities directly. So, the whole scene becomes a living map of where the function vanishes, where it blows up, and how the surrounding geometry bends in response.

Mathelirium

14,941 views • 1 month ago

orbit: isn’t there an intensity that comes with first love? kyungsoo: that’s right~ orbit: i’m not sure if it’s okay to ask this kind of question, but have you experienced first love? kyungsoo: i have. i was in my third year of high school~ orbit: in your third year of high school? whoa… how was it? kyungsoo: at that time, it was the first time i cried because of someone of the opposite sex… it’s a first love that still lingers… orbit: you can’t forget it… kyungsoo: i can’t forget it~ orbit: that’s right~ kyungsoo: i think the emotional memories of first love come from the mistakes made~ orbit: ah… so it was more of the lacking side? kyungsoo: it was the lacking side~ because at that time, i really enjoyed hanging out with my friends. so, i spent a lot of time hanging out with them, but i didn’t spend much time (with my first love), right? then i regretted it and cried. and that kind of love, which was very painful, is what becomes first love, i guess… orbit: ah… it’s true that you can’t forget your first love… scientifically speaking~

orbit: isn’t there an intensity that comes with first love? kyungsoo: that’s right~ orbit: i’m not sure if it’s okay to ask this kind of question, but have you experienced first love? kyungsoo: i have. i was in my third year of high school~ orbit: in your third year of high school? whoa… how was it? kyungsoo: at that time, it was the first time i cried because of someone of the opposite sex… it’s a first love that still lingers… orbit: you can’t forget it… kyungsoo: i can’t forget it~ orbit: that’s right~ kyungsoo: i think the emotional memories of first love come from the mistakes made~ orbit: ah… so it was more of the lacking side? kyungsoo: it was the lacking side~ because at that time, i really enjoyed hanging out with my friends. so, i spent a lot of time hanging out with them, but i didn’t spend much time (with my first love), right? then i regretted it and cried. and that kind of love, which was very painful, is what becomes first love, i guess… orbit: ah… it’s true that you can’t forget your first love… scientifically speaking~

🌸 사랑둥이 귀염둥이 세훈이 🌸

80,195 views • 1 year ago

haechan : "the standard for a successful album? i don’t want them to just like the album because it’s by haechan but i want them to feel happy and proud of being my fan because the album’s so good, that’s the first criterion. and the second criterion is i want it to be acknowledged well as an r&b album. not just an album that tries r&b, but really to be approved as an r&b album, that’s the second goal."

haechan : "the standard for a successful album? i don’t want them to just like the album because it’s by haechan but i want them to feel happy and proud of being my fan because the album’s so good, that’s the first criterion. and the second criterion is i want it to be acknowledged well as an r&b album. not just an album that tries r&b, but really to be approved as an r&b album, that’s the second goal."

ؘ ndaa #TASTE

25,213 views • 11 months ago

Earth orbits the Sun, and the Sun orbits the center of the galaxy... but what is the Milky Way itself orbiting? The Milky Way is not orbiting a single object. Instead, it is moving around a shared center of mass alongside the Andromeda galaxy. While most of the universe is being pushed apart by dark energy, the gravity within our "Local Group" is strong enough to pull these two galaxies toward each other in a slow "cosmic dance." This movement isn't a clean, circular orbit; it is a direct path toward a massive collision and merger that will occur in about 4 to 5 billion years.

Earth orbits the Sun, and the Sun orbits the center of the galaxy... but what is the Milky Way itself orbiting? The Milky Way is not orbiting a single object. Instead, it is moving around a shared center of mass alongside the Andromeda galaxy. While most of the universe is being pushed apart by dark energy, the gravity within our "Local Group" is strong enough to pull these two galaxies toward each other in a slow "cosmic dance." This movement isn't a clean, circular orbit; it is a direct path toward a massive collision and merger that will occur in about 4 to 5 billion years.

Cosmos Archive

47,683 views • 6 months ago

You're watching spacetime in motion...two spinning black holes orbit, twist, and merge, dragging the very geometry of the universe into a luminous storm. Their union births a single remnant that fires smoke-wreathed jet as gravitational waves ring the cosmic fabric itself. 🤩😍 #Math #Physics #Astrophysics #SciArt #MathArt

You're watching spacetime in motion...two spinning black holes orbit, twist, and merge, dragging the very geometry of the universe into a luminous storm. Their union births a single remnant that fires smoke-wreathed jet as gravitational waves ring the cosmic fabric itself. 🤩😍 #Math #Physics #Astrophysics #SciArt #MathArt

Mathelirium

42,531 views • 8 months ago