Astronomers find cosmic "barcode" from distant galaxy
A glimpse of a galaxy so far away that what we’re seeing is eight billion years in the past has offered astronomers a key to understanding what they say is nature’s overall consistency throughout the universe.
A joint research team from Swinburne University of Technology and the University of Cambridge found that electromagnetism emanating from the distant galaxy was the same as that from our own planet. The discovery is significant for researchers looking to find a common, connecting reference point between everything in our extremely varied universe. They say, think of it as a “barcode” that can be scanned and read to understand more about our cosmic surroundings.
The astronomers made the find by studying a quasar — a remote celestial object that emits bright, large quantities of energy — that was behind the distant galaxy. Some of the object’s light was absorbed by gas in the galaxy, casting shadows in specific hues.
“The pattern of colors tells us how strong electromagnetism is in this galaxy, and because the quasar is one of the brightest ones known, we were able to make the most precise measurement so far,” study lead author Srđan Kotuš, a Swinburne PhD candidate, explained in a press release.
Kotuš added that the electromagnetism in the faraway galaxy was equal to that of Earth, within one part per million. Electromagnetism is one of the four known fundamental forces in nature along with gravity; the strong force that holds an atom’s nucleus together; and the weak force that results in radioactive decay.
“Electromagnetism determines almost everything about our everyday world, like the light we receive from the Sun, how we see that light, how sound travels through the air, the size of atoms and how they interact,” Swinburne’s Michael Murphy, study co-author, said. “But no one knows why electromagnetism has the strength it has and whether it should be constant, or vary, and why.”
To measure electromagnetism, researchers use spectrographs, which measure the pattern of shadows cast by a quasar. This team used the instruments at the European Southern Observatory’s Very Large Telescope (VLT) as well as the 3.6-m Telescope located in Chile.
The findings certainly didn’t answer all of the researchers’ questions about the mysteries of the universe. Murphy stressed that finding that electromagnetism “is constant over more than half the universe’s age” actually adds to the mystery. The key challenge is determining why this is the constant.
“It’s remarkable that distant galaxies provide such a precise probe of such a fundamental question. With even larger telescopes now being built, we’ll be able to test it even better in the near future,” Murphy said.
