How does ALMA combine many dishes to study distant galaxies and forming planets?

The Atacama Large Millimeter Array (ALMA) functions as a radio interferometer, a system that combines signals from multiple antennas to achieve high-resolution observations.

ALMA utilizes 66 parabolic dishes that act in concert to capture radio waves from the same astronomical source. Because these dishes are spaced apart, the incoming radio signals reach each antenna at slightly different times. By using a variable-delay mechanism to compensate for these time differences, the signals are made to interfere with one another. This process allows the array to achieve a resolving power equivalent to that of a single, massive dish up to 16 km (10 miles) in diameter.12

This sophisticated integration of signals provides the high angular resolution necessary to study radiation emitted by dust and gas in distant galaxies and during the formation of extrasolar planets.1