Image List

This map of the near side of the Milky Way, a combination of an artist's conception and real data points, shows several spiral arms. The sun (red circle) is located on a spur between two of the arms. Blue circles mark star-forming regions whose distances have been accurately measured using parallax.

Very Long Baseline Interferometry provides extremely high precision that can extend use of the parallax technique to many more celestial objects. Parallax is a direct means of measuring cosmic distances by detecting the slight shift in an object's apparent position in the sky caused by Earth's orbital motion.