Elements important to life on Earth are evenly distributed across the bulk of the universe, says a new study.
In a survey of hot, X-ray-emitting gas in the Virgo galaxy cluster, the researchers found that the common chemicals needed to make stars, planets and people were evenly distributed across millions of light-years early in cosmic history.
The Virgo cluster, located about 54 million light-years away, is the nearest galaxy cluster and the second brightest in X-rays. The cluster is home to more than 2,000 galaxies, and the space between them is filled with a diffuse gas so hot it glows in X-rays.
Using Japan's Suzaku X-ray satellite, a team led by Aurora Simionescu, astrophysicist at the Japan Aerospace Exploration Agency (JAXA) in Sagamihara, acquired observations of the cluster along four arms extending up to five million light-years from its centre.
The study showed that the chemical elements in the cosmos are well mixed, showing little variation on the largest scales.
The same recipe thought to be responsible for the solar system's makeup was at work throughout the universe.
This likely happened when the universe was between two and four billion years old, a period when stars were being formed at the fastest rate in cosmic history.
"This means that elements so important to life on Earth are available, on average, in similar relative proportions throughout the bulk of the universe," Simionescu explained.
"In other words, the chemical requirements for life are common throughout the cosmos," Simionescu noted.
In an earlier study, Suzaku data showed that iron was distributed uniformly throughout the Perseus Galaxy Cluster, but information about lighter elements mainly produced by core-collapse supernovae was unavailable.
The Virgo Cluster observations supply the missing ingredients.
The new study detected iron, magnesium, silicon and sulfur all the way across a galaxy cluster for the first time.
The elemental ratios are constant throughout the entire volume of the cluster and roughly consistent with the composition of the sun and most of the stars in our own galaxy.
Because galaxy clusters cover enormous volumes of space, astronomers can use one example to extrapolate the average chemical content of the universe, the researchers said.
The findings were reported in the The Astrophysical Journal Letters.
