Light and Photons

A Fundamental Manifestation of Matter

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.

Radiation Filtered by Earth's Atmosphere

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.

Understanding the Spectrum to Understand the Universe

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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