A radio telescope array being built in the highest, driest desert in the world has photographed two colliding galaxies for its first public test shots.

The new images reveal a flurry of star formation within thick clouds of gas and dust at the Antennae Galaxies’ impact zone, 45 million light-years away. Older star-forming regions appear as a faint orange in the image while the youngest — some 3 to 4 million years old — glow bright yellow.

The same murky material that leads to star birth also blocks visible wavelengths of light, but the Atacama Large Millimeter/submillimeter Array (ALMA)...