Light is a form of energy carried by elementary particles called photons. It results from fundamental physical processes, such as electronic transitions in atoms or interactions between charged particles. This wave-particle duality makes light a central phenomenon in modern physics.
The atmosphere only allows a small portion of the electromagnetic radiation emitted by celestial bodies to pass through. Short waves, such as gamma rays or extreme ultraviolet rays, are absorbed in the upper layers, while very long waves are reflected or deflected. The optical window—that of visible light—is one of the few frequency ranges that effectively reaches the Earth's surface.
The light that reaches us carries valuable information about celestial objects: temperature, chemical composition, speed, and internal structure. By studying the electromagnetic spectrum, astronomers can analyze phenomena invisible to the naked eye and explore regions of the Universe otherwise inaccessible. Light is thus one of the most powerful tools for understanding the cosmos.
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The Perception of Radiant Cold Explained by Physics 
Sprites and Cosmic Rays: The Ghostly Lightning of the Atmosphere 
Principle of
absorption and emission of a photon 
The Femtosecond Laser: From Ultra-Short Time to Extreme Power 
The World of Color 
The colors of the rainbow 
The Nature of Light 
Plasma Lamp and Field Concept 
What is Vantablack? 
Michelson-Morley Experiment 
Redshift calculation (z) 
Spectacular airglow in France 
All the Light of the Electromagnetic Spectrum 
Solar Pillars: Celestial Mirages and Light Phenomena 
The Speed of Light: A Universal Constant 
The incredible precision of the second 
Aberration of Light: The Great Gathering, Blueshift, and Dazzling 
Why do elementary particles have no mass? 
Polar Auroras: Lights of the Solar Wind 
Blue Moon or Ice Moon: Understanding These Lunar Phenomena 
Gravitational Lenses: When Spacetime Becomes a Mirage 
Optical Illusions: Deceptions and Mysteries of Visual Perception 
Traveling Light: How a Photon Leaves the Sun to Reach Earth? 
Bioluminescence of living organisms 
Laser light 
We do not see with our eyes but with our brain 
Differences between heat and temperature 
Zodiacal Light: Reflection of Interplanetary Dust 
Explanation of the 8 of the analemma 
The Antitwilight Arch: Earth's Shadow 
How many photons to heat a cup of coffee? 
Spectroscopy: A Key to Analyzing the Invisible World 
Why is Cherenkov light blue? Explanations and physical phenomenon 
The lights of the Sun 
What is a Wave? 
Planck's equation and black body light 
Energy Conservation