ALMA, the world's most powerful radio telescope is now operating. It is positioned 5km above sea-level in Chile.
The Atacama large milllimetre/submillimetre array is the largest, most complex telescope ever built.
ALMA's purpose is to study processes occurring a few hundred million years after the formation of the Universe when the first stars began to shine.
The BBC science correspondent say its work should help explain why the cosmos looks the way it does today.
ALMA consists of an array of linked giant antennas on top of the highest plateau in the Atacama desert, 1500 km north of Santiago.
It has been under construction since 2003. With the addition of new antennas, the telescope has been able to see progressively deeper into the cosmos and discern star formation processes in ever greater detail.
Full testing and commissioning of its 20th antenna has enabled ALMA to record events that have never been seen before.
