Supernova dust found in snow from Antarctica
Researchers have found dust from an exploded star, or supernova, in snow from Antarctica, according to a study published this month.
The discovery could provide lessons about the solar system’s history and place in its surrounding environment, the study, published August 12 in the Physical Review Letters, said.
A supernova occurs when a star explodes and produces clouds or gas and dust enriched with radioisotopes. Some of that dust from one or more stars that exploded within the last 20 million years fell to Earth sometime in the past 20 years, according to the study. Now it’s been found in snow taken from the sparsely inhabited continent.
“I’m really glad and happy to actually see something which traveled billions of billions of kilometers through space and is millions of years old,” said Dominik Koll, a nuclear astrophysicist who led the discovery and co-authored the study. “To be able to use the data on Earth that’s pretty amazing.”
Koll told CNN that researchers made the discovery after shipping 500 kg (about 1,100 pounds) of snow from Antarctica to a research facility in Munich, Germany.
The researchers picked the remote area precisely because it is largely untouched. They chose to test snow because “it is the purest material you can find,” Koll said.
The snow was melted down and sifted through. Materials in it were incinerated and tested using equipment sensitive enough to detect anomalies.
The samples tested positive for iron-60.
Most iron in the universe is iron-56. Iron-60, which has more neutrons making it unstable to radioactive decay, is present on Earth only from either cosmic explosions or nuclear weapons. Researchers were able to determine that the most likely source of the iron-60 found in the Antarctic snow was star dust, Koll said.
However, it’s unclear whether the Earth is currently in a dust cloud or if the discovery is of the remnants of a cloud that passed through years ago, Koll said.
Regardless, the finding could yield clues about the Earth’s place in the larger universe and information on the structure and origin of the cloud.
“You learn quite a lot about the dynamics, about the solar neighborhood,” Koll said. “It means all our understanding about the process and dynamics, that it all fits together.”
Koll said the next step is to test deposits from older ice cores to find out when and where the supernova happened and when our solar system entered into the cloud of space dust.