"A gravitational lens is a distribution of matter or a point particle between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer."
The bending of light caused by the curvature of spacetime.
General Relativity: The fundamental theory of gravity, which describes gravity as the curvature of spacetime caused by mass and energy.
Equations of motion: Mathematical equations describing how objects move in the presence of gravity.
Geodesics: The paths that objects follow in curved spacetime, which are equivalent to the straightest possible paths.
Black holes: Massive objects with so much gravity that they have a significant effect on the surrounding space, including the gravitational lensing of light.
Galaxy clusters: Groups of galaxies held together by their combined gravity, which can create significant gravitational lensing effects.
Einstein rings: The circular or nearly circular shapes formed by gravitational lensing, where a background object is distorted into a ring around a foreground object.
Strong lensing: The most significant gravitational lensing effects, where the background object is highly distorted, and multiple images can be visible.
Weak lensing: More subtle gravitational lensing effects, where the background object is only slightly distorted, and only one image is visible.
Microlensing: Gravitational lensing by a single object, such as a star or planet, which can create temporary brightening or fading of a background object.
Dark matter: A form of matter that does not interact with light, but which makes up most of the mass in the universe and has a significant effect on gravitational lensing.
Observational techniques: The methods used to study gravitational lensing, including direct imaging, spectroscopy, and the analysis of statistical data.
Strong gravitational lensing: This is a type of lensing where the lensing galaxy or cluster is strong enough to bend light from the background source into multiple images or an arc. The lensed images can be bright and distinct, enabling detailed analysis of the background source and the gravitational lens itself.
Weak gravitational lensing: This is a type of lensing where the lensing object is not strong enough to produce multiple images, but still causes a slight distortion of the background source. These distortions can reveal information about the distribution of mass in the lens and the surrounding environment.
Microlensing: This is a type of gravitational lensing where a foreground object, such as a star or planet, passes in front of a background star. The gravity of the foreground object causes the background star's light to be bent and focused, producing a temporary increase in brightness.
Cosmic gravitational lensing: This is a type of gravitational lensing that occurs on a very large scale, such as when the mass of a galaxy or cluster of galaxies bends and focuses the light from a much more distant object. The lensing effect can reveal information about the large-scale structure of the universe.
Gravitational lensing by black holes: This is a type of gravitational lensing where the lensing object is a black hole. The intense gravity of the black hole can bend and focus light from more distant objects, including stars and galaxies.
Fold lensing: This is a type of gravitational lensing where a source behind a galaxy produces an arc in front of the galaxy as the light from the source is bend due to the gravity of the galaxy.
Quasar Lensing: This is a type of gravitational lensing which is observed when a foreground galaxy acts as a lens, magnifying the more distant quasar behind it.
Cluster lensing: This is a type of gravitational lensing where the gravitational force of galaxy clusters is powerful enough to bend light from objects behind them. The galaxies within the cluster act as individual lenses, producing multiple images of the background object.
Refraction Lensing: This is a type of gravitational lensing that occurs due to the refraction of light by the gravitational field of a lensing object.
Relativistic Lensing: This is a type of lensing seen only in the vicinity of massive objects like a massive star or blackhole where the distortion of space-time is significant enough to bend the light from a source seen at great distances.
"This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity."
"Treating light as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity."
"Orest Khvolson (1924) and Frantisek Link (1936) are generally credited with being the first to discuss the effect in print."
"However, this effect is more commonly associated with Einstein, who published an article on the subject in 1936."
"Fritz Zwicky posited in 1937 that the effect could allow galaxy clusters to act as gravitational lenses."
"It was not until 1979 that this effect was confirmed by observation of the Twin QSO SBS 0957+561."
"A distribution of matter or a point particle between a distant light source and an observer is required for gravitational lensing to occur."
"The light from the source bends as it travels toward the observer due to the gravitational lens."
"The amount of bending is one of the predictions of Albert Einstein's general theory of relativity."
"Newtonian physics predicts only half of the bending predicted by general relativity."
"Einstein made unpublished calculations on the subject in 1912."
"This effect is known as gravitational lensing."
"Matter distribution, such as a cluster of galaxies or a point particle, is capable of bending the light from the source."
"The effect of gravitational lensing was observed in the Twin QSO SBS 0957+561 in 1979."
"Light is treated as corpuscles traveling at the speed of light."
"Fritz Zwicky proposed in 1937 that galaxy clusters could act as gravitational lenses."
"No, gravitational lensing cannot be explained fully by Newtonian physics."
"Einstein made unpublished calculations on the subject in 1912."
"Einstein published an article on the subject in 1936."