Is the Light You See from a Flashlight One Photon or Made of Photons?

Introduction

Light, an enigma that has puzzled scientists and philosophers for centuries, is both a wave and a particle. Different perspectives of its nature have been proposed, with notable contributions from Einstein and Bohr. This article delves into the modern understanding of the nature of light from flashlights and whether this light is made up of photons or indeed one photon.

The Nature of Light: From a Wave to a Particle

Light, an electromagnetic wave described by Maxwell's equations since 1865, can also be viewed as a stream of tiny particles. However, despite this attractive idea, it is not fully realized. The key to understanding light lies in the behavior of electrons and the 'pilot wave' they emit.

Electrons and the Pilot Wave

Light does not exist as a beam of photons between a source and a target surface. Instead, it is the electron's journey that produces an electromagnetic 'pilot wave'. This pilot wave is the precursor to visible light and is not visible. There is no 'light' in the space between a flashlight and the wall it illuminates—it is the surface that transforms this wave into visible light.

The pilot wave concept, introduced by Louis de Broglie, suggests that electrons emit an outgoing circular wave. This wave is maximally blue-shifted in the forward direction, with decreasing shift for angles away from the forward direction. When this wave hits a surface, it interacts with its molecules, leading to reflection, refraction, or absorption, depending on the surface's properties.

Light from Flashlights and Glass Enclosures

The light from flashlights and other glass-enclosed sources is created within the glass enclosure and then passes through, potentially filtered by the color of the enclosure. This filtered light travels to the target surface and can either create reflections or pass through, depending on the target surface's properties.

In a dark room, if you shine a flashlight on a wall, you see the light on the wall but not the beam creating it. The beam itself is not visible; it is the interaction of this beam with the wall's surface that makes the light apparent.

Diffraction and Spectral Analysis

The amount of blue shift at the high end of the spectrum is also determined by the electron's speed and the energy it possesses when it emits the wave. This is why red and blue stars appear different to the human eye. When observing a star directly, the spectrum cast on the retina in the human eye determines the light we see. This is the same principle that applies to any light source you see, whether initially created or a secondary reflection.

Further Reading

More detailed information on the nature of light and its behavior can be found in the following resources:

Detailed Extension of Answers on Quora Further Readings on Photons and Electromagnetic Waves

Understanding the nature of light is a fascinating subject with implications in various fields, from astronomy to quantum mechanics. This article aims to provide a simplified yet accurate explanation of light's behavior from flashlights and the underlying physics.