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Dark matter evidence
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Galaxy rotation curves show more gravity than visible matter explains.
Orbital speeds in galaxies stay flat far out instead of falling like √(1/r), and cluster lensing exceeds visible mass, implying extra non-luminous matter.
The Bullet Cluster separates the gas from the mass.
The nature of dark matter remains unknown.
In more detail
Dark matter is an invisible form of matter that interacts gravitationally. Evidence includes galaxy rotation curves and gravitational lensing, which show more mass than visible matter accounts for.
Real-world uses
- Cosmological simulations include dark matter to reproduce large-scale structure.
- Dark matter searches use underground detectors and particle colliders.
- Galaxy rotation curves are used to show that galaxies need much more mass than the visible stars and gas provide.
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Frequently asked questions
Is dark matter proven?
Gravitational effects are well established, but the particle nature of dark matter is still unknown.
Is it the same as dark energy?
No. Dark matter clumps and attracts, while dark energy drives accelerated expansion.
Is dark matter proven?
Its gravitational effects are well established, but its nature is still unknown and is an active area of research.
Related topics in Gravitation & Orbits
Black holes · Schwarzschild radius · Neutron stars and white dwarfs · Newton's shell theorem · Gravitational self-energy · Inertial vs gravitational mass