Iron, the sixth most abundant element in the universe, serves many vital functions for humanity. Mechanically, it’s the main component of the steel used in constructing everything from computer electronics to skyscrapers. Chemically, it forms structures in the hemoglobin molecule that permits oxygen transport through the blood. Geologically, the movement and cooling of the iron in Earth’s core sustains the magnetic field surrounding the planet and the plate tectonics that reshape its surface. And a new study shows that this important element here on Earth owes its existence to violent conditions in the early universe.
For all practical purposes, the universe contained only hydrogen and helium after the first few minutes. Stellar interiors form the heavier elements, but need some extreme conditions to distribute them. Supernova explosions, massive black hole eruptions, and galaxy collisions that astronomers witness today serve that role, but the rates of these events pale in comparison to conditions in the early universe.
One way to investigate this early epoch is to look at large galaxy clusters to study the distribution of heavy elements like iron in clusters of galaxies. If the iron formed in the cluster, astronomers would see an uneven distribution of iron with concentrations near the galaxies. But recent measurements of the iron distribution in the Perseus cluster of galaxies reveals a far more uniform distribution. By observing different locations in the cluster, astronomers mapped out the iron distribution at certain spherical coordinates through the cluster. Analysis of the iron map showed a constant value of iron enrichment out to the edge of the cluster.1
This constant value means that the iron formed before the galaxies in the cluster took shape more than ten billion years ago. In other words, stars during the first 2–3 billion years of the universe’s history produced abundant iron (and other elements vital to life), and the high rate of supernovae, massive black hole activity, and galaxy collisions spread these life-essential elements throughout the universe.
An end to this early, tumultuous epoch was necessary because the radiation produced from all the violent activity would severely impact life’s origin and development (and likely exterminate it even if life somehow started). Yet without the elements formed and dispersed during this early period, life would not have the vital components it requires.
Past studies demonstrate a pattern seen here on Earth. Extreme, hostile-to-life conditions occur prior to a remarkable advance in the type of life observed in the fossil record. Examples include the Late Heavy Bombardment, the Great Oxygenation Event and the “snowball” Earth. This research extends the pattern out to include the development of the universe. Upheavals followed by benign conditions suitable for life point to an intelligent Agent who works toward the end of having a planet like Earth teeming with diverse life where humans can witness and ponder it all.