What you see: The yellow star bends light rays (shown curving) from the distant white star. The blue exoplanet orbiting the yellow star adds extra magnification, creating brightness spikes that astronomers measure to detect planets.
Gravitational Microlensing 3D Visualizer
By Claude Code
Gravitational microlensing detects exoplanets by observing how a massive star's gravity magnifies and bends light from a distant background star. When the stars align, the foreground star acts as a lens, creating magnification spikes. An orbiting exoplanet adds extra brightening - revealing its presence without direct imaging.
How it works: A massive star's gravity bends spacetime, causing light rays to curve. Peak magnification reaches 1.34 at perfect alignment. An exoplanet orbiting the foreground star creates additional brightening spikes that astronomers measure. Microlensing events typically last days to weeks.
| Parameter | Value / Range |
|---|---|
| Detection sensitivity | Planets 0.5 to 10 AU from parent star |
| Einstein radius | 0.3 to 3 milliarcseconds (stellar-mass lenses) |
| Exoplanets discovered | Over 100 using this technique |
Educational approximation: This visualizer shows the key concept using simplified procedural geometry, not a full relativistic simulation. The actual phenomenon involves spacetime curvature and precise calculations.
Frequently Asked Questions
How do astronomers actually detect exoplanets using microlensing?
They monitor millions of stars in dense galactic regions, watching for sudden brightening events. When a foreground star's gravity magnifies a background star, the brightness increases by a measurable amount and follows a predictable curve. If an exoplanet orbits the lens star, its gravity adds an extra spike to the light curve - revealing the planet's presence.
Why is microlensing useful when other detection methods exist?
Microlensing finds planets at large orbital distances (0.5 - 10 AU) and low masses that other methods miss. It has discovered planets around multiple-star systems where other techniques fail. It also does not require the planet to pass in front of its star, so it finds planets in almost any orbital configuration.
Is this a real simulation or just a visualization?
This is an educational visualization, not a full general-relativity simulation. It shows the core concept - light bending around a massive object and exoplanet-induced brightening - using simplified geometry and procedural rendering. Real microlensing calculations involve precise ephemeris data, spacetime curvature, and numerical integration.
How fast does light actually bend near a massive star?
The angle depends on the mass and distance. For our Sun, light grazes at an angle of about 1.75 arcseconds (which was famously measured during the 1919 solar eclipse). For stellar-mass black holes or neutron stars, the bending is much more dramatic - light can be bent by tens or hundreds of degrees.
How many exoplanets have been discovered using microlensing?
As of 2026, over 100 exoplanets have been detected via microlensing. Notable discoveries include planets in the habitable zone around other stars and planets in binary star systems where planet formation was thought to be unlikely.