Researchers have found traces of iron-60, a rare radioactive isotope created by the explosion of massive stars, in ice tens of thousands of years old, providing support for the idea that the solar system moves within an interstellar cloud originating from an ancient supernova.
Earth is sailing through the radioactive remnants of an ancient star that exploded, and the proof has been preserved in the Antarctic ice.
Scientists have discovered new evidence that Earth is moving through a cloud of ancient supernova debris left behind by a star that exploded long ago. Researchers examining ice tens of thousands of years old in Antarctica have found iron-60, a rare radioactive isotope created when massive stars explode. The findings suggest that the local interstellar cloud surrounding our solar system contains material left over from an ancient supernova.
Material from an ancient supernova reached Israel
Iron-60 is created inside massive stars and thrown into space in supernova explosions. Geological evidence has already shown that Earth was exposed to iron-60 from nearby supernovae millions of years ago. But in modern times, no stellar explosions have occurred that could provide new iron-60.
This raised questions when scientists recently discovered traces of iron-60 in relatively young Antarctic snow.
"Our idea was that the local interstellar cloud contains iron-60 and could store it for long periods. As the solar system moved through the cloud, Earth could have picked up this material. But we couldn't prove it at the time," explains Dr. Dominic Cole.
In recent years, Cole and his colleagues have analyzed additional samples, including deep-water sediments formed up to 30,000 years ago. These samples also contained iron-60, but the scientists still couldn't rule out competing explanations.
The new Antarctic ice cores studied are between 40,000 and 80,000 years old. The researchers say the results are a strong indication that the local interstellar cloud is the source of the radioactive material.
"This means that the clouds around the solar system are related to a star that exploded. And for the first time, we have an opportunity to investigate the origin of these clouds," says Cole.
The solar system passes through the local interstellar cloud.
Scientists believe that the solar system entered the local interstellar cloud a few tens of thousands of years ago and will exit it again in a few thousand years. The researchers say that the solar system is now close to the edge of the cloud.
To investigate the timing, the team analyzed an ice core spanning the period when the solar system may have first entered the cloud. By comparing the results from the Antarctic ice core with previous measurements of earlier ice and deep-water sediments, the researchers found that the Earth received less iron-60 between 40,000 and 80,000 years ago compared to today.
"It suggests that we were previously in an environment with a lower iron-60 content, or that the cloud itself shows strong changes in density," explains Cole.
The team also found that the iron-60 signal varies significantly over relatively short cosmic timescales, just tens of thousands of years. This allowed the researchers to reject alternative theories, including the idea that the material is simply the decaying remnants of supernova explosions millions of years ago.
for the scientific article DOI: 10.1103/nxjq-jwgp
Quick FAQ:
What is iron-60?
Iron-60 is a rare radioactive isotope of iron. It is created primarily inside massive stars and is ejected into space during supernova explosions.
Why is the discovery of iron-60 in Antarctica important?
Because it indicates that material originating from a stellar explosion reached Earth and was preserved in layers of ice for tens of thousands of years.
Is the find dangerous to the Earth?
No. These are extremely small amounts of a radioactive isotope, which serve as scientific evidence for the orbit of the solar system within interstellar matter.
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