Dark Matter

Dark Matter is a term used in Physics and Astronomy to describe a type of matter that does not interact with Electromagnetic radiation, making it invisible to the entire electromagnetic spectrum. Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.

Overview

Dark matter is estimated to constitute 85% of the matter in the universe and about a quarter of its total mass–energy density. Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen.

Evidence for Dark Matter

The evidence for dark matter comes from its gravitational influence on galaxies and galaxy clusters. For example, the Rotation curve of spiral galaxies can only be explained if there is a substantial amount of dark matter in the galaxy's halo.

Composition

The exact composition of dark matter is unknown, but it is believed to be composed of Exotic particles that do not interact with light or other forms of electromagnetic radiation, and are thus invisible to traditional detection methods.

Dark Matter and the Universe

Dark matter plays a central role in structure formation and Big Bang cosmology. Without dark matter, the universe would not have evolved into its current state, with its vast web of galaxies and large-scale structures.

See Also

• Dark Energy
• Big Bang
• Galaxy formation and evolution
• Cosmology

References

Dark Matter Resources
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