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Gravitational lensing
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Mass bends light, forming arcs and multiple images.
A mass bends the path of light, deflecting it by 4GM/(c²b) (twice Newton's value). Lensing produces multiple images or rings, and shows dark matter.
Eddington's 1919 eclipse deflection of 1.75″.
Lenses can magnify distant galaxies.
In more detail
Gravitational lensing bends light from distant objects around massive foreground objects, as predicted by general relativity. It can magnify and distort background images.
Real-world uses
- Astronomers use lensing to map dark matter in galaxy clusters.
- Lensing has revealed distant galaxies too faint to see otherwise.
- Astronomers use gravitational lensing to map dark matter in galaxy clusters, which bends light from distant galaxies.
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Frequently asked questions
Is lensing caused by a force?
In general relativity, it is the bending of spacetime, which bends light paths.
Was it confirmed?
Yes. Observations during a 1919 solar eclipse first confirmed light bending by the Sun.
Is lensing a real bending of light?
Yes. Gravity curves spacetime, so light follows a curved path near massive objects.
Related topics in Gravitation & Orbits
Effective potential · Binary stars · Weighing the Sun and planets · Gravitational waves · Black holes · Schwarzschild radius