• Concept: Think of spacetime diagrams as a way to picture the four-dimensional reality we live in.
• Quick Fact: Introduced by Hermann Minkowski in 1908.
• Diagrams
  • Position (x) on the x-axis 📏
  • Time (t) on the y-axis ⌛️
• Note: This is opposite to the distance-time graphs you might remember.
• Example: Think of it like a game screen where time is vertical, and space is horizontal.
• a. Stationary Particle 🛑
  • It remains on the x-axis as time increases.
  • Its worldline (trajectory) is straight up.
• b. Moving Particle 🚀
  • Starts at the origin.
  • Its worldline is slanted if it's moving at a constant speed.
  • Curved if it's accelerating.
• c. Super-fast Particle (Speed Limit) 🚗💨
  • Nothing can move faster than light! 🚫💡
  • There's a max slope or gradient for the worldline.
  • Fun Fact: A photon's worldline is shown by this max gradient.

Real-world Analogy: Think of the worldlines as the trails left behind by skywriters. A straight line means the plane was stationary, a slant means it was moving, and a curve means it was accelerating!

• Why?: To understand the weird stuff relativity brings to the table!
• Fun Change: Sometimes, you'll see the time axis labeled as "ct" instead of just "t." This makes time and position have the same units.

Convention: Physicists sometimes set the speed of light (c) as 1 to make math easier.

• So, 0.95c is like saying something's moving at 95% the speed of light!

• If you love trigonometry, this is for you.
• The angle θ between a particle's worldline and the time axis can be found using tan θ = v/c.
• When something's moving as fast as light (v = c), θ = 45°.

Analogy: Imagine a steep hill representing the speed of light. Anything on that hill is moving at the speed of light.