The solar system is currently moving through a cloud of supernova debris – news from the web

Landmarks

• Our sun orbiting the center of the Milky Way, a galaxy with a diameter of about 100,000 light years containing 2000 billion stars.
• The Sun sits in one of the galaxy’s outer spiral arms, Orion’s 107 arm, which is about 25,000 to 28,000 light years from the galactic center where a supermassive black hole is located.
• Even if the star spins at a speed of about 239 km / s, a complete revolution takes about 250 million years.

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During its orbital journey, the solar system comes into contact with interstellar matter. This is partly made up of radioactive elements ejected into space as a result of supernovae.

These compounds enter the atmosphere of its planets or are deposited on other objects there, such as asteroids.

You should know that, on Earth, oceanic sediments are real geological archives: they conserve the composition of their environment over long periods of millions of years.

This material can therefore be detected, and this is precisely what scientists from Germany, Austria, and Australia have achieved by analyzing sediment samples taken from the seabed about 1000 kilometers off the south-western tip of the Australia.

In search of radioactive iron

Scientists led by Prof. Anton Wallner of the Australian National University of Canberra mainly focused on the presence of a particular isotope: iron 60 (⁶⁰Fe). To find it, they used a technique called accelerator mass spectrometry which extends the sensitivity of conventional mass spectrometry and measures very low levels of elements or isotopes.

The ⁶⁰Fe is not found naturally on Earth. The presence of this radioactive isotope is therefore an indicator of supernovae explosions over the past millions of years.

Their work published in the journal Proceedings of the National Academy of Sciences (New window) (in English) show that the Earth has been moving in an interstellar cloud for at least 33,000 years.

Their work also made it possible to detect traces of ⁶⁰Fe that would have been deposited on the seabed around 2.6 million years ago, and possibly others around 6 million years ago.

This information suggests that our planet has traveled through some clouds of matter from supernovae in the last millions of years.

For a few thousand years, the solar system has been moving through a denser cloud of gas and dust, known as the local interstellar cloud, the origins of which are unclear., explain the researchers in a press release released by the German laboratory Helmholtz-Zentrum Dresden-Rossendorf.

Researchers estimate that over the past 33 millennia, a total of just 60 grams of iron-60 from stardust have reached the earth’s surface.

A group from the Technical University of Munich has also detected the isotope in snow samples from Antarctica.

Scientists have in the past found traces of this rare isotope in samples of lunar soil brought back to Earth by astronauts from the Apollo 12, 15 and 16 missions.

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Source: Radio-Canada | Science