Astrometry: Mapping the Motions of Stars

Astrometry is the precise measurement of stars’ positions and movements.
It is the oldest branch of astronomy, dating back to ancient sky charts.
By tracking stellar shifts, astrometry helps measure distances using parallax.
It reveals how stars move through the Milky Way, mapping galactic dynamics.
Astrometry is vital for detecting unseen companions like exoplanets and brown dwarfs.
Even tiny wobbles in a star’s motion can signal orbiting planets.
ESA’s Hipparcos mission in the 1990s measured positions of 100,000 stars.
Its successor, Gaia, is mapping over a billion stars with unprecedented accuracy.
Gaia’s data is creating the most detailed 3D map of our galaxy ever made.
Astrometry underpins the cosmic distance ladder, scaling the universe from nearby stars outward.