Universe's Violent Youth Seeded the Cosmos with Iron Billions of Years Ago

Billions of years ago, our universe went through a violent and turbulent period. Now, scientists are learning a bit more about our universe's youth. It turns out that exploding stars and black holes sowed the early cosmos with heavy elements.

About 10 billion years ago, iron was distributed throughout a massive galaxy cluster. Yet in order to get a better view of this particular time, the researchers analyzed 84 sets of X-ray telescope observations from the Japanese-US Suzaku satellite. More specifically, they examined iron distribution throughout the Perseus cluster, a large grouping of galaxies about 250 million light-years away.

"We saw that iron is spread out between the galaxies remarkably smoothly," said Norbert Werner, one of the researchers, in a news release. "That means it had to be present in the intergalactic gas before the Perseus cluster formed."

This even distribution actually supports the idea that the galaxies were created at least 10 to 12 billion years ago during a time of intense star formation. During this time of intense star formation, billions of exploding stars created vast quantities of heavy elements in the alchemical furnaces of their own destruction. This was the time when black holes in the hearts of galaxies were at their most energetic.

Yet in order to get an even closer glimpse at this time, the scientists looked through the Perseus cluster in eight different directions. They focused on the hot, 10-million-degree gas that fills the spaces between galaxies and found the spectroscopic signature of iron reaching all the way to the cluster's edges. This indicated that it's likely the iron came from a single type of supernovae, called the Type Ia supernovae.

In a Type Ia supernova, a star explodes and releases all of its material into space. Currently, the researchers believe that at least 40 billion Type Ia supernovae must have exploded within a relatively short period on cosmological time scales in order to release that much iron and have the force to drive it out of the galaxies.

"With measurements like these, the Suzaku satellite is having a profound impact on our understanding of how the largest structures in our universe grow," said Steven Allen, one of the researchers, in a news release. "We're really looking forward to what further data can tell us."

The findings are published in the journal Nature.