Scientists Have Spotted Some of the Oldest Light in the Universe

With help in deep space, a Hawaiian telescope captures a quasar dating back to the days of the first stars.

very old quasar
NASA, ESA, Xiaohui Fan (University of Arizona)

Studying a faraway quasar, scientists have encountered some of the oldest light in the universe. Thanks to a powerful telescope on earth and a galaxy acting as a gravitational lens, scientists have been able to observe the quasar despite its distance of 12.8 billion light-years away from Earth.

Quasars are extremely bright objects in space, possibly the brightest objects in the universe. They lie at the center of distant galaxies and are powered by matter collapsing . It's hard to comprehend their energy—they can give off thousands of times more energy than the entire Milky Way. None are anywhere close to Earth; they seem to only exist in remote, distant locations of the universe.

Powerful telescopes like the , located in Hawaii and Chile, can help research them. The Gemini North, located in Maunakea, Hawaii, has an 8.1-meter-diameter optical/infrared telescope used for deep space exploration. And using that, it was able to discover a galaxy whose bending gravity magnified the quasar's light. This sort of bending was in his general theory of relativity.

Studying the light from the quasar allowed scientists to see its extreme age.

"If it weren't for this makeshift cosmic telescope, the quasar's light would appear about 50 times dimmer," says Xiaohui Fan of the University of Arizona, who led the study, in a . "This discovery demonstrates that strongly gravitationally lensed quasars do exist despite the fact that we've been looking for over 20 years and not found any others this far back in time."

The beam of light was dated back to a time period known as the Epoch of Reionization (EoR), which some scientists "one of the least understood epochs in the universe's evolution." During EoR, which occurred approximately a few hundred million years after the Big Bang, the predominantly neutral gasses of the universe suddenly became ionized. That ionization led to the formation of the first stars, and then the first galaxies.

Any remnants of the EoR are valuable for studying the universe in its earliest days.

"This is one of the first sources to shine as the universe emerged from the cosmic dark ages," says Jinyi Yang of the University of Arizona, another member of the discovery team. "Prior to this, no stars, quasars, or galaxies had been formed, until objects like this appeared like candles in the dark."

The intensity of the quasar, known by scientists as J0439+1634, suggests that the black hole it surrounds is approximately 700 million times larger than our solar system's sun. Scientists estimate that JO439 shines with the brightness of approximately 600 trillion suns.

Luckily, the galaxy acting as a lens was unusually dim, allowing scientists to get a clearer contrast. "If this galaxy were much brighter, we wouldn't have been able to differentiate it from the quasar," says Fan. "We don't expect to find many quasars brighter than this one in the whole observable universe."

With a quasar that bright, scientists are eager for further exploration. There are plans for the , also based in Chile, to look within 150 light-years of the quasar for further clues to the universe's formative years. If and when the James Webb Space Telescope launches, J0439 would be a perfect target.


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