This weekend, a collaborative French-Chinese satellite mission is set to embark on a quest to uncover the secrets of gamma-ray bursts, the universe’s most potent explosions. These incredible phenomena, whose light has traveled billions of light years to reach Earth, hold the potential to reveal insights into the early universe.
Despite their significance, gamma-ray bursts have proven elusive due to their fleeting nature. The Space Variable Objects Monitor (SVOM) aims to address this challenge. Scheduled to launch on a Chinese Long March 2C rocket from the Xichang space center in Sichuan province on Saturday, the SVOM spacecraft will be equipped with four instruments—two Chinese and two French—and will orbit Earth at an altitude of 625 kilometers (390 miles).
Chen Lan, a specialist in China’s space program, emphasized the “political significance” of this joint mission, noting that it demonstrates the possibility of continued scientific cooperation even during strained international relations.
A Serendipitous Discovery
SVOM’s mission is to use its X-ray capabilities to locate the origins of gamma-ray bursts, which are detected in the sky approximately once daily. Bertrand Cordier, the chief scientist for France’s contribution to SVOM, explained that the investigation into these bursts began during the Cold War. In 1967, U.S. satellites, monitoring nuclear test ban treaty compliance, inadvertently detected a gamma-ray flash—initially mistaken for a nuclear explosion on Earth before its cosmic origin was identified.
Since that initial discovery, several missions, including NASA’s Swift telescope, have advanced our understanding of these bright and powerful events. Gamma-ray bursts, the most energetic phenomena known in the universe, emit gamma rays and last from fractions of a second to several seconds. Following the initial explosion, an “afterglow” can persist for hours, traversing the universe to reach Earth, according to Susanna Vergani of the Paris Observatory.
Clues to the Early Universe
The origins of gamma-ray bursts vary. Shorter bursts likely result from collisions between massive neutron stars or a neutron star being consumed by a black hole. Longer bursts are believed to originate from the supernovae of the universe’s earliest, massive stars, significantly larger than our Sun. The most ancient gamma-ray burst identified to date occurred just 630 million years after the Big Bang, providing a glimpse into the universe’s infancy.
Gamma-ray bursts enable scientists to explore the distant universe, shedding light on the chemical processes that gave birth to the first stars and galaxies. Additionally, as the light from these explosions travels through space, it carries the imprints of the gas clouds it passes, potentially revealing the distribution of chemical elements throughout cosmic history.
Assessing the Threat
Regarding the potential threat to Earth, Cordier reassured that the Milky Way’s age makes it unlikely to host the massive collisions that generate gamma-ray bursts. Furthermore, Earth’s atmosphere offers protection against more distant bursts.
Given the brief duration of gamma-ray bursts, scientists will be racing against the clock to gather data. Upon detecting a burst, SVOM will promptly alert a team of scientists on standby around the clock. Within minutes, a network of ground-based telescopes will aim at the burst, aiming to capture as much information as possible before it fades away
