Quasar Reveals Chemistry of Ancient Universe

Light from the most distant quasar yet seen reveals details about the chemistry of the early universe. Credit: ESO/M. Kornmesser

Content provided by Nola Taylor Redd, SPACE.com Contributor



“We’re looking back to when the first stars were turning on, but also when the first chemicals were made,” Robert Simcoe, of Massachusetts Institute of Technology, told SPACE.com.

A Beacon Through the Fog


ANALYSIS: The Quasar That Acts Like a Reverse Gravitational Lens



“You can imagine the quasar is like a beacon, peering through some fog,” Simcoe said. “What we’re trying to do is study the properties of the fog.”


With a team of astronomers, Simcoe used a specially-built spectrograph instrument on the Magellan Telescope in Chile to study the chemistry of the cloud. They found an absence of the heavy elements that exist in the universe today.


NEWS: Dead Quasar Leaves Ghost Behind

The early universe was composed of hydrogen and helium. It wasn’t until the first stars ignited that heavier elements were created, and when these stars exploded in fiery deaths, space was seeded with the elements necessary to build planets. The lack of these elements in the early cloud of gas indicates that the stars around it have not yet had time to mix with their surroundings.


“The only thing efficient enough to strip electrons away from protons is starlight, the light from hot stars,” Simcoe said.


But star formation in the early universe didn’t start in a single area. The first generation of stars were scattered across space. So just because the region around the newly-discovered quasar isn’t showing signs of stellar activity doesn’t mean that no early stars existed at the time.

“In different spots in the universe, we expect star formation to turn on at different times,” Simcoe said. “Basically what it means is that stars hadn’t turned on yet in a global sense.”

The research was published Wednesday (Dec. 5) in the online version of the journal Nature.

Depends on Your Perspective

Simcoe and his team can’t tell whether the gas is part of a newly formed galaxy, or whether it makes up the diffuse material between collections of stars. The location of the hydrogen would give further insight into the early universe.

ANALYSIS: No Time Dilation for Distant Quasars?


However, in order for the gas to be part of the protogalaxy, the line of sight between Earth, the quasar, and the galaxy would have to be just right. According to Simcoe, the odds of that lineup are slim.


“The odds of seeing intergalactic gas is essentially 100 percent,” Simcoe said, noting that such clouds would exist along all lines of sight.


“If we can find even a couple more things that people are searching hard for, then we should be able to settle that,” Simcoe said.



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