Investigating snow in the Antarctic, researchers first discovered interstellar dust that recently fell to Earth.
These results could shed light on the mysterious interstellar clouds. The solar system flies regularly, scientists said. Tons of extraterrestrial dust caused by passing comets, asteroid collisions, and exploding stars fall to the ground daily. However, scientists may not find it until long after the fall, so details of recent interactions between the solar system and its environment are lacking.
In contrast, this new study analyzes relatively recent interstellar dust, and the results can provide insights into mysterious phenomena of interstellar clouds and their relationship to our solar system.
"Scientists could use our findings to figure out how the solar quarter was formed," said study lead Dominik Knoll, an experimental nuclear physicist at the Australian National University in Canberra, Space.com said. "We know something about distant galaxies and stars and much about our solar system, but the nearer environment of our solar system needs to be studied more closely."
Related: NASA's Stardust Mission Brings Cosmic Dust to Earth (Photos)
To search for potentially untouched samples of interstellar dust scientists rallied about 1
To identify the components of the snow, the researchers took it to Munich, melted it, filtered out the solids, burned the residue, and analyzed the pattern of light emitted. They discovered the presence of two rare, weakly radioactive isotopes : iron-60 and manganese-53. (Isotopes of an element vary in the number of neutrons they possess in their nuclei, for example, the most naturally occurring iron isotope has iron -3030 neutrons, while iron-60 has 34 neutrons.)
Researchers, the most likely source for Iron-60 was a supernova a powerful explosion of a giant dying star bright enough to briefly outshine all other stars in its host galaxy. Other natural ways of producing iron-60 produce only up to a tenth as much. However, iron-60 and manganese-53 can also be produced when atomic fragments, referred to as cosmic radiation encounter interplanetary dust. However, the researchers found a higher ratio of iron-60 to manganese-53 than they would have expected from this mechanism.
The researchers also investigated whether the iron-60 was derived from nuclear weapons or power plants. However, they found that the production of iron-60 and manganese-53 from these sources should be negligible.
The scientists therefore concluded that these radioactive isotopes were most likely forged in a nearby supernova, the interstellar sowing clouds from gas and dust. In the study, the researchers suggested that this dust precipitates on the Earth's surface as it passes through the solar system.
Future studies of interstellar dust in older snow and ice could shed light on the formation and structure of neighboring interstellar dust clouds and the history of their interactions with the solar system, the researchers said.
The scientists reported their results online on August 12 in the journal Physical Review Letters.