Hot dark matter is a cosmological research area focused on studying dark matter candidates that were relativistic, with thermal velocities near the speed of light, at the epoch of matter–radiation equality. This field investigates how such fast-moving particles, typically light neutrinos with eV-scale masses, affect structure formation by free-streaming and erasing primordial density fluctuations below a characteristic scale, leading to a top-down hierarchy of structure assembly. Research emphasizes constraining the hot dark matter fraction via cosmic microwave background anisotropies, large-scale structure surveys, Lyman-α forest data, and neutrino mass measurements, and comparing these constraints with those for cold and warm dark matter models.
A new theory for the origins of dark matter suggests that fast-moving, neutrino-like dark particles could have decoupled from Standard Model particles far earlier than previous theories had suggested.
Dark matter has two central properties: it has mass like regular matter, and unlike regular matter, it reacts weakly or not at all with light. Neutrinos satisfy these two criteria, but neutrinos move through space at nearly ...
Astronomy
Oct 26, 2025
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A mysterious phenomenon at the center of our galaxy could be the result of a different type of dark matter.
Astronomy
Mar 10, 2025
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The reason we call dark matter dark isn't that it's some shadowy material. It's because dark matter doesn't interact with light. The difference is subtle, but important. Regular matter can be dark because it absorbs light. ...
Astronomy
Sep 26, 2024
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