Astronomers have discovered carbon in a galaxy observed just 350 million years after the Big Bang, in observations that raise the possibility that the conditions for life have been present almost since the dawn of time.
Observations made by the James Webb Space Telescope indicate that huge amounts of carbon were released when the first generation of stars exploded in supernovae. Carbon is known to have seeded the first planets and is the building block of life as we know it, but was previously thought to have appeared much later in cosmic history.
“This is the earliest ever detection of an element heavier than hydrogen,” said Professor Roberto Maiolino, an astronomer at the University of Cambridge and co-author of the findings. “It’s a huge discovery.”
“Finding a large amount of carbon in such a distant galaxy suggests that life could potentially have appeared very early in the universe, really close to the cosmic dawn.”
The very early universe was almost entirely made up of hydrogen, helium and a tiny amount of lithium. Every other element—including those that made up Earth and humans—formed in stars and was released during supernovae, when stars explode at the end of their lives. With each new generation of stars, the universe became enriched with progressively heavier elements until rocky planets formed and life became a possibility.
Carbon is an essential element in this process, as it can clump into dust grains in the swirling disk around stars and eventually snowball to the oldest planets. The carbon enrichment was previously thought to have occurred about 1 billion years after the Big Bang.
The latest research dates the oldest carbon footprint to just 350 million years old, suggesting that carbon was released in large quantities in the supernovae of the very first generation of stars in the universe. This doesn’t change estimates of when life began on Earth, about 3.7 billion years ago, but it does suggest that some of the criteria for life emerging elsewhere in the universe were present much earlier than expected.
“The very first stars are the holy grail of chemical evolution because they are composed only of primordial elements and behave very differently from modern stars,” said Dr. Francesco D’Eugenio, an astrophysicist at the Kavli Institute for Cosmology in Cambridge. the main author of the findings. “By studying how and when the first metals formed inside stars, we can establish a time frame for the earliest steps on the path that led to the origin of life.”
The galaxy, which is the fifth most distant galaxy observed, is small and compact – about 100,000 times smaller than the Milky Way. “When we observe it, it’s just an embryo galaxy, but it could develop into something quite large, the size of the Milky Way,” D’Eugenio said. “But it’s quite massive for such a young galaxy.
Analysis of the spectrum of light coming from the galaxy provided a reliable detection of carbon and preliminary detections of oxygen and neon. “It’s a long way from carbon to DNA, but this shows that these key elements are already there in principle,” Maiolino said.
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Dr Rafael Alves Batista, an astrophysicist at the Sorbonne University in Paris, who was not involved in the latest findings, said: “The result is a big leap forward and it’s something we didn’t know before.”
However, he said it was not possible to extrapolate from the carbon detection the probability of life. “That’s not a leap I would make,” he said. “Most of these. [early] stars are too massive so they die too quickly. Even if there are planets, I’m not very optimistic that they would have the conditions for life. The findings are very interesting, but I don’t think they are enough to solve anything.”
The findings are to be published in the journal Astronomy & Astrophysics.