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Why can electromagnetic radiation travel through empty space?

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Diagram of a tree leaf illustrating photosynthesis, with arrows showing sunlight, water, and carbon dioxide entering the leaf and sugars and oxygen being produced. A person is shown beside the tree to demonstrate the exchange of oxygen and carbon dioxide between plants and animals. — electromagnetic radiation Diagram of photosynthesis showing how water, light, and carbon dioxide are absorbed by a plant to produce oxygen, sugars, and more carbon dioxide.

Electromagnetic radiation can travel through empty space because it does not require a physical medium to propagate, unlike mechanical waves such as sound or water waves.12

Instead, electromagnetic radiation consists of self-propagating, time-varying electric fields and magnetic fields that are mutually linked. According to the theory developed by James Clerk Maxwell, a changing electric field continually gives rise to a changing magnetic field, and vice versa. This ongoing interaction allows the wave to sustain itself as it moves through space at the speed of light.321

While scientists once hypothesized the existence of an ether as a medium for this propagation, experiments—most notably the Michelson-Morley experiment—failed to detect it. It is now understood that these fields have their own existence in space, independent of any material medium. In modern quantum theory, this radiation is also described as a flow of photons through space.243