A groundbreaking observation by the James Webb Space Telescope has unveiled the earliest known supernova, dating back to a time when the universe was only 730 million years old. This remarkable discovery follows a powerful gamma-ray burst detected earlier this year, which originated from a distant source in the cosmos. Astronomers pinpointed this stellar explosion with the Webb telescope, setting a new record for the oldest supernova ever observed.
The gamma-ray burst was first detected on March 14, 2023, by the Space-based multi-band astronomical Variable Objects Monitor (SVOM) mission. Within hours, additional telescopes were employed to identify the source’s location and estimate its timing within the cosmic timeline. According to Andrew Levan, an astrophysics professor at Radboud University and lead author of a study published in Astronomy and Astrophysics Letters, “There are only a handful of gamma-ray bursts in the last 50 years that have been detected in the first billion years of the Universe. This particular event is very rare and very exciting.”
Details of the Discovery
The gamma-ray burst lasted approximately ten seconds, indicating it was likely caused by the explosive death of a massive star, rather than the collision of two neutron stars or a neutron star and a black hole. The Webb telescope’s observations took place on July 1, 2023, about three months after the initial detection, allowing time for the supernova to increase in brightness. This characteristic is typical for supernovae, which generally brighten rapidly over weeks.
Since this supernova occurred in the early universe, its light was subject to redshift due to the expansion of the universe, making it appear dimmer and requiring advanced technology like Webb to detect it effectively. Once the astronomers focused on the ancient supernova, comparisons with more recent explosions revealed astonishing similarities.
Significance of the Findings
Despite expectations that the oldest known supernova would differ due to the fewer heavy elements present in early stars, the findings showed it resembled modern supernovae closely. “We went in with open minds,” said Nial Tanvir, a professor at the University of Leicester and co-author of the study. “And lo and behold, Webb showed that this supernova looks exactly like modern supernovae.”
The implications of this discovery extend beyond a mere record-breaking observation. The team of astronomers plans to utilize the Webb telescope to study the afterglow of distant gamma-ray bursts, which will provide further insights into galaxy formation and evolution. As Levan notes, “That glow will help Webb see more and give us a ‘fingerprint’ of the galaxy.”
This breakthrough underscores the capabilities of the James Webb Space Telescope in unraveling the mysteries of the early universe, providing a clearer understanding of cosmic events shortly after the Big Bang. As researchers continue to analyze these findings, the quest to understand the universe’s origins and evolution enters an exciting new phase.
