The technique lay dormant until it was reinvented by the French astronomer Antoine Labeyrie in the 1970s. More than a dozen optical arrays have been built. Most were prototypes that served their purpose and were phased out. Astronomers hope these facilities will generate the technical demonstrations and scientific momentum required to bring interferometric arrays into the mainstream of astronomical research. Dramatic advances in stellar astrophysics should rapidly follow as we obtain the first detailed views of stars other than the sun.
Astronomers are also eager to study sources that are small, faint and complex.
Meanwhile the advantages of interferometry are not limited to ground-based astronomy. The scientific return in understanding of galaxies and their evolution will be immeasurable. SIM could fly within five years. The TPF could launch within 10 years. Francesco Paresce is project scientist for the European Southern Observatory's Very Large Telescope Interferometer .