Knowra Gravitational microlensing Gravitational microlensing Gravitational microlensing is the temporary magnification of a distant source’s light by a foreground object whose gravity bends the light. The lens usually appears too faint or too close in angle to resolve separately.
Einstein radius : The characteristic angular or physical scale of a gravitational lens, set by its mass and the source, lens, and observer distances. Crossing this scale sets the event’s characteristic duration and magnification.
Microlensing planet detection : The discovery of planets through brief anomalies in microlensing light curves caused by planetary companions to lens stars. A planet’s gravity creates a short-lived signal within or alongside its star’s event.
Strong gravitational lensing : Gravitational lensing that produces conspicuous multiple images, arcs, or rings through a massive, well-aligned lens. Unlike typical microlensing, its separate images are often spatially resolved.
Albert Einstein : The physicist who developed general relativity, which predicts the gravitational deflection of light. His theory supplies the physical basis for magnification by a foreground mass.
Exoplanet : A planet orbiting a star beyond the Solar System. Microlensing expanded exoplanet discovery to cold, distant, and free-floating worlds.
Einstein ring : A ring-shaped image formed when a source, lens, and observer align exactly in a gravitational lensing system. Exact alignment produces this ideal image; imperfect alignment yields separated images that usually remain unresolved.
OGLE : The Optical Gravitational Lensing Experiment, a long-running survey that monitors dense stellar fields for microlensing and other variable phenomena. Its surveys have found many events and planets toward the Milky Way’s central regions.
Weak gravitational lensing : Small, statistical distortions in the apparent shapes of many background sources caused by foreground mass. It measures population-wide shape changes rather than isolated transient brightening.
Einstein's 1936 lensing paper : A short paper in which Albert Einstein calculated lensing by a star and noted that its images would be difficult to observe separately. It established the point-mass lens geometry later used to describe microlensing.
Free-floating planet : A planetary-mass object that is not gravitationally bound to a star. A brief lensing event can reveal such a planet without a luminous host.
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