Cosmic findings

Chile's ALMA Telescope opens with a big bang

History of the universe revised as astronomers release groundbreaking data at the inauguration of the world's largest ground-based observatory.

Wednesday, March 13, 2013  
Nineteen of ALMA’s 66 antennas, all pointing at the same spot in the sky. Photo by ESO. Nineteen of ALMA’s 66 antennas, all pointing at the same spot in the sky. Photo by ESO.


This is Chile joined a packed press room at the opening of the Atacama Large Millimeter/submillimeter Array (ALMA) in the mountains outside San Pedro this week, and as hoped, the completion of this unprecedented feat of human engineering was complemented by the release of historic findings.


Using the unrivaled sensitivity of ALMA's antenna array, astronomers have identified the most distant galaxies ever seen. Data suggests that intense star birth - known as "starbursts" - in the regions analyzed occurred 12 billion years ago, just 1.7 billion years after the start of the universe, and a full billion years before previous estimates of the first star formation.


"This is an great example of astronomers from around the world collaborating to make an amazing discovery with a state-of-the-art facility," said Daniel Marrone of the University of Arizona, a team member of the study published in Nature. "This is just the beginning for ALMA and for the study of these starburst galaxies. Our next step is to study these objects in greater detail and figure out exactly how and why they are forming stars at such prodigious rates."


ALMA


The key to ALMA’s sensitivity lies in both the wavelengths it detects and the design of its antenna array. ALMA observes the millimeter and sub-millimeter wavelengths that exist between infrared and radio waves on the electromagnetic spectrum. Cool-temperature objects - such as the dust created by the birth and death of stars on the edge of the universe - give off these wavelengths, allowing ALMA to analyze matter formerly invisible to us.


Wavelength determines what an astronomer can observe, though a telescope's diameter is crucial for an image's sharpness. By strategically positioning and synchronizing all 66 of ALMA's 23 ft (7 m) and 40 ft (12 m) antennas, the array has power equivalent to a telescope with a 10 mile (16 km) diameter - ten times more powerful than the Hubble Telescope!


Incredibly, the "starburst" study only used 16 of the array's antenna, suggesting that future studies that employ ALMA's full power will lead to even more sensational breakthroughs.


By Angus McNeice


Tune in tomorrow for more on-the-ground coverage of the ALMA inauguration in Chile’s Atacama Desert. 


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