The Milky Way Over Chile’s ‘Very Large Telescope’ Yields a Secret Hidden Since the Big Bang


Billions of years ago the intensity of the electromagnetic interaction was different at opposite ends of universe. That's the fascinating conclusion of a group of physicists in Australia, who have studied light from ancient quasars and discovered that the fine-structure constant, known as α, has changed in both space and time since the Big Bang.

In 1998 John Webb, Victor Flambaum and colleagues at the University of New South Wales began looking for evidence of variations in α by studying light coming from distant quasars. Radiation from these extremely bright objects has traveled for billions of years before reaching Earth, passing en route through ancient clouds of gas along the way.

Some of the light is absorbed at specific wavelengths that reveal the chemical composition of the cloud. Within the absorption spectrum is the eponymous "fine structure" from which the value of α can be extracted.

The team has so far studied hundreds of quasars in the northern sky and concluded that billions of years ago α was about one part in 100,000 smaller than it is today. This, however, remains a controversial result that is not accepted by all physicists.

Now, Webb and colleagues have analysed 153 additional quasars in the southern sky using the Very Large Telescope (VLT) in Chile (above) and have made an even more startling discovery. They found that in the southern sky, α was about one part in 100,000 larger 10 billion years ago than it is today. The value in the northern sky was still smaller, as found before.


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