A powerful blast of gamma-rays that may have been the most powerful cosmic explosion since the Big Bang caused significant disturbance around Earth when it struck our planet, new research finds.
The incredibly bright and long-lasting gamma-ray burst — dubbed the "brightest of all time," or the BOAT, and officially designated GRB 221009A — was detected in October 2022 by an array of high-energy-detecting satellites around Earth.
The BOAT is believed to have occurred when a massive star located more than 2 billion light-years away exploded, creating a supernova before collapsing into a black hole. When the blast's radiation struck our planet, the BOAT seems to have generated severe effects in Earth's ionosphere. This layer of the atmosphere, which extends from about 30 to 600 miles (50 to 1,000 kilometers) above the planet's surface, is rich in electrically charged particles, and investigating these effects could reveal if any of Earth's mass extinctions might have resulted from gamma-ray bursts.
"We've been measuring gamma-ray bursts since the 1960s, and this is the strongest ever measured," Pietro Ubertini, a scientist at the National Institute for Astrophysics, said in a statement. Ubertini is a co-author of the research, published Nov. 14 in the journal Nature Communications.
Related: A supernova may have triggered a mass extinction on Earth 359 million years ago
Just how bright is the BOAT gamma-ray burst?
When scientists detected the BOAT in October 2022, they found it to be at least 10 times as powerful as the next-most-energetic gamma-ray burst, Live Science previously reported.
"Photons have been detected from this gamma-ray burst that has more energy than the Large Hadron Collider (LHC) produces," Jillian Rastinejad, a Northwestern University doctoral candidate who was not involved in the new research but was part of the team that detected the BOAT, previously told Live Science. Rastinejad explained that while the LHC can generate energies as high as 13 tera electron volts (TeV) — or 13 trillion electron volts — GRB 221009A produced photons with energies of at least 18 TeV.
Thus, it is little surprise that during the 800 seconds that the BOAT gamma-rays pelted Earth, they should have imparted enough energy to disturb the ionosphere for several hours. The authors of the new study reasoned that the China Seismo-Electromagnetic Satellite (CSES), which orbits Earth in the ionosphere, should have detected this disturbance, despite having never detected the effects of gamma-ray bursts before. This lack of detection led scientists to hypothesize that by the time gamma-ray bursts from distant exploding stars reached Earth, they were no longer powerful enough to visibly shake up the conductivity of the ionosphere.
The BOAT was different, however, with its effect on the ionosphere obvious in the form of strong electric-field variations. The effect of the BOAT was also measurable in the atmosphere closer to Earth's surface, via radio signals bouncing between this surface and the ionosphere.
"Notably, this disturbance impacted the very lowest layers of Earth's ionosphere, situated just tens of kilometers above our planet's surface, leaving an imprint comparable to that of a major solar flare," Laura Hayes, a solar physicist at the European Space Agency who has previously researched the BOAT gamma-ray burst, said in the statement. "Essentially, we can say that the ionosphere 'moved' down to lower altitudes, and we detected this in how the radio waves bounce along the ionosphere."
The fact that the BOAT had a measurable effect on the ionosphere even though its photons traveled 2 billion years to reach Earth reinforces the idea that a massive star dying in Earth's vicinity would be catastrophic for life on our planet.
A nearby gamma-ray burst, which could also be created by colliding neutron stars, could not only affect the ionosphere but also strip our planet's ozone layer, leaving life on Earth exposed to harmful ultraviolet radiation from the sun.
With the effects of the BOAT now seen in the ionosphere, the team will hunt for similar data collected by CSES, which they will correlate with other gamma-ray bursts measured by other satellites.
A nearby gamma-ray burst, which could also be created by colliding neutron stars, could not only affect the ionosphere but also strip our planet's ozone layer, leaving life on Earth exposed to harmful ultraviolet radiation from the sun.
With the effects of the BOAT now seen in the ionosphere, the team will hunt for similar data collected by CSES, which they will correlate with other gamma-ray bursts measured by other satellites.
