一般相対性理論の記事

According to general relativity, objects in a gravitational field behave similarly to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket (left) as it does on Earth (right), provided that the acceleration of the rocket is equal to 9.8 m/s2 (the acceleration due to gravity on the surface of the Earth).

一般相対性理論時空の歪みが解き明かす宇宙の真理

2026年8月12日続きを読む →

$The second-order Cauchy stress tensor T {\displaystyle \mathbf {T} } describes the stress experienced by a material at a given point. For any unit vector v {\displaystyle \mathbf {v} } , the product T ⋅ v {\displaystyle \mathbf {T} \cdot \mathbf {v} } is a vector, denoted T ( v ) {\displaystyle \mathbf {T} (\mathbf {v} )} , that quantifies the force per area along the plane perpendicular to v {\displaystyle \mathbf {v} } . This image shows, for cube faces perpendicular to e 1 , e 2 , e 3 {\displaystyle \mathbf {e} _{1},\mathbf {e} _{2},\mathbf {e} _{3}} , the corresponding stress vectors T ( e 1 ) , T ( e 2 ) , T ( e 3 ) {\displaystyle \mathbf {T} (\mathbf {e} _{1}),\mathbf {T} (\mathbf {e} _{2}),\mathbf {T} (\mathbf {e} _{3})} along those faces. Because the stress tensor takes one vector as input and gives one vector as output, it is a second-order tensor.$

テンソルとは何か数学的定義から物理学・機械学習への応用まで

テンソル線形代数多重線形写像物理学

2026年8月12日続きを読む →

Diagram of two masses attracting one another

万有引力の法則宇宙を支配する基本原理とその歴史

万有引力の法則アイザック・ニュートン重力定数古典力学

2026年8月12日続きを読む →

Two bodies orbiting their center of mass (red cross)

重力加速度の仕組みと宇宙における多様な値

重力加速度万有引力の法則一般相対性理論自由落下

2026年8月12日続きを読む →

Isaac Newton's Cannonball. Path C depicts a circular orbit.

円軌道のメカニズム天体力学における基本原理と物理的特性

円軌道天体力学軌道速度向心加速度

2026年8月11日続きを読む →

$Except for the few stars in the foreground (which are bright and easily recognizable because only they have diffraction spikes), every speck of light in the composite photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 2 trillion galaxies.[1] From the Hubble eXtreme Deep Field.$