Breaking: Space Dust from a Stellar Explosion Found in Antarctica Snowfall

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Cosmic dust found in Antarctic snow was possibly birthed in a distant supernova millions of years ago. The interstellar journey of the dust eventually brought the material to Earth, where scientists discovered the ancient grains.

This dust was isolated because it contains an iron isotope called iron-60, which is commonly released by supernovas but very rare on Earth.

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In the quest for elusive space dust, scientists examined more than 1,100 lbs. (500 kilograms) of surface snow that they gathered from a high-altitude region of Antarctica near the German Kohnen Station. 

In that particular location, the snow would be mostly free of contamination from terrestrial dust, the researchers reported in a new study. 

Then the investigators sent the still-frozen snow to a lab in Munich. Here, it was melted and filtered to isolate dust particles that might contain traces of material from space. When the scientists inspected the incinerated dust using an accelerator mass spectrometer, they spotted the rare iron-60 isotope—a relic of an ancient supernova.

Space is a place full of dust and rich with particles expelled by supernovas and shed from planets, asteroids, and comets. 

Our solar system is at present fleeting through a large cloud of space dust termed the Local Interstellar Cloud (LIC), and grains from this cloud found on Earth could potentially tell much about how our sun and its planets interact with cosmic dust.

To find out if the space dust came from a distant supernova, the scientists first had to rule out whether it originated within our solar system. Illuminated dust shed by planets and other bodies can hold iron-60, but exposure to cosmic radiation also creates another isotope: manganese-53. 

The researchers compared ratios of iron-60 and manganese-53 in the Antarctic grains, finding that the quantity of manganese was much lower than it would have been in the dust were local.

There is a possibility that iron-60 may have been on our planet during its infancy, but the researchers wrote in the study that all of this rare isotope has long since decayed on Earth. 

Nuclear bomb tests may have created and spread iron-60 across the planet, but calculations revealed that the quantity of the isotope produced by such nuclear tests would have been much lower than the amount of iron-60 detected in Antarctica’s snow.

Iron-60 is also created in nuclear reactors, still, the volume of the isotope that reactors generate is “insignificant” and the scientists said, is confined to the reactors where it is made. 

Till date, even serious nuclear accidents like the Fukushima Daiichi nuclear power plant disaster in 2011, didn’t release iron-60 to the environment in measurable quantities, as per the study. 

Formerly, iron-60 on Earth was spotted only in ancient deep-sea deposits or in rocks that originated in space, “like meteorites or on the moon,” the scientists reported online on Aug. 12 in the journal Physical Review Letters.

The researchers wrote, “By ruling out terrestrial and cosmogenic sources [shaped by cosmic rays], we conclude that we have found, for the first time, recent iron-60 with interstellar origin in Antarctica”.