The Mystery of Light: Particle or Wave?

Introduction

• Light is essential for life and understanding the universe.
• Despite its importance, light doesn't behave as expected under scrutiny.
• This lecture explores why light is difficult to understand and how it behaves differently when observed.

The Basics of Light

• Isaac Newton (1700s): Light as particles called "corpuscules".

• Thomas Young (1801): Proved light is wave-like using the double-slit experiment.

  • **Double-Slit Experiment: **
    • Light shown through two narrow slits formed an interference pattern, not two bands.
    • Demonstrated light's wave nature through constructive and destructive interference.

The Photoelectric Effect (1905)

• Scientists observed electrons being emitted when light shone on metal surfaces.
• Higher light intensity expected to increase electron velocity but didn’t.
• Albert Einstein: Proposed light travels in packets called photons.
  • Higher frequency, not intensity, affects electron speed.
  • Earned a Nobel prize for this work.

Wave-Particle Duality

• Double-slit revisited with single photons showed particle-like behavior initially but wave-like interference over time.
• Light (particle) seems to travel through both slits and interfere with itself (wave) when not observed.
• Observation collapses this behavior, causing light to behave like a particle.

The Three-Polariser Paradox

• Polarising lenses block light based on oscillation orientation.
• Adding a third, angled lens allows light to pass through all three, showing probabilistic behavior.
• Suggests light doesn’t have a fixed orientation but snaps to one when observed.

Probabilistic Nature of Light

• Light behaves in discrete quantities (quantum behavior).
• Observers collapse light's probabilistic state to concrete points.
• Light and all energy and matter are probabilistic at quantum levels.

Remaining Mysteries

• Light’s true nature and behavior under observation remain unresolved.
• Possible correlation with harmonics theory, but mechanism unknown.
• Implications for understanding reality and the universe constantly evolving.

Conclusion

• Light shows wave-particle duality and probabilistic nature under scrutiny.
• Understanding light's nature may result in significant scientific breakthroughs.
• Reality and the universe appear less certain and more probabilistic than previously thought.