Asteroids@home

Asteroids@home is a volunteer computing project that uses distributed computing to derive three-dimensional shape models and spin parameters of asteroids from photometric observations known as lightcurves — records of how an asteroid's brightness changes over time as it rotates and is illuminated by sunlight from different angles.

The mathematical problem of inverting a lightcurve to recover an asteroid's shape is highly degenerate: many different shape-and-spin combinations can produce similar brightness variations. The project addresses this by testing millions of possible parameter combinations (rotation period, spin axis orientation, shape model vertices) for each asteroid, evaluating how well each model reproduces the observed lightcurve data. This brute-force search over a vast parameter space is ideally suited to distributed computing.

Run by the Department of Astronomy at Charles University in Prague (Czech Republic), the project processes data from ground-based photometric surveys and individual observers worldwide. To date, Asteroids@home has derived reliable shape and spin models for thousands of asteroids — dramatically expanding the Database of Asteroid Models from Inversion Techniques (DAMIT), a publicly available resource used by planetary scientists worldwide.

Understanding asteroid shapes, spin states, and surface properties is directly relevant to planetary defense — the ability to predict and potentially deflect an asteroid on a collision course with Earth depends critically on knowing its physical characteristics. NASA's DART mission (2022), which successfully altered an asteroid's orbit, is exactly the kind of planetary-defense mission that depends on the shape and spin knowledge Asteroids@home systematically builds for thousands of bodies.