The first discovery of a supernatural radioactive isotope on Earth has made scientists rethink the origins of the elements on our planet.
Small traces of plutonium-244 along with radioactive iron-60 were found in the crust of the sea. There is evidence of violent cosmic events around Earth two isotopes millions of years ago.
Star explosions, or supernovas, form many heavy elements in the periodic table, including elements important for human life, such as iron, potassium, and iodine.
To create heavier elements such as gold, uranium, and plutonium, it was thought that a more violent event might be needed, such as the merger of two neutron stars.
However, a study led by Professor Anton Wallner of The Australian National University (ANU) suggests a more complex picture.
“The story is complex – it was probably produced in plutonium-244 supernova explosions or it may have been omitted from a much older, but even more spectacular event, such as a neutron star explosion,” said the study’s lead author, Professor Wallner.
Any plutonium-244 and iron-60 that existed when the Earth formed four billion years ago from interstellar gas and dust have long since decayed, so current traces of them must have arisen from recent cosmic events in space .
The dating of the sample confirms that there have been two or more supernova explosions near the Earth.
“Our data may be the first evidence that a supernova actually produces plutonium-244,” Professor Wallner said. “Or perhaps it was in the interstellar medium before the supernova was shut down, and it was pushed into the solar system along with the supernova ejecta.”
Professor Wallner also holds joint positions at Helmholtz-Zentrum Dresden-Rosendorff (HZDR) and Technical University Dresden in Germany, and has conducted this work with researchers from Australia, Israel, Japan, Switzerland and Germany.
The VEGA accelerator was used to identify small traces of plutonium-244 at the Australian Atomic Science and Technology Organization (ANSTO) in Sydney.
Small traces of plutonium-244 along with radioactive iron-60 were found in the crust of the sea. There is evidence of violent cosmic events around Earth two isotopes millions of years ago.
Star explosions, or supernovas, form many heavy elements in the periodic table, including elements important for human life, such as iron, potassium, and iodine.
To create heavier elements such as gold, uranium, and plutonium, it was thought that a more violent event might be needed, such as the merger of two neutron stars.
However, a study led by Professor Anton Wallner of The Australian National University (ANU) suggests a more complex picture.
“The story is complex – it was probably produced in plutonium-244 supernova explosions or it may have been omitted from a much older, but even more spectacular event, such as a neutron star explosion,” said the study’s lead author, Professor Wallner.
Any plutonium-244 and iron-60 that existed when the Earth formed four billion years ago from interstellar gas and dust have long since decayed, so current traces of them must have arisen from recent cosmic events in space .
The dating of the sample confirms that there have been two or more supernova explosions near the Earth.
“Our data may be the first evidence that a supernova actually produces plutonium-244,” Professor Wallner said. “Or perhaps it was in the interstellar medium before the supernova was shut down, and it was pushed into the solar system along with the supernova ejecta.”
Professor Wallner also holds joint positions at Helmholtz-Zentrum Dresden-Rosendorff (HZDR) and Technical University Dresden in Germany, and has conducted this work with researchers from Australia, Israel, Japan, Switzerland and Germany.
The VEGA accelerator was used to identify small traces of plutonium-244 at the Australian Atomic Science and Technology Organization (ANSTO) in Sydney.
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