The quantity of cosmic dust that trickles down to Earth each year ranges between several thousand and ten thousand tons. Most of the tiny particles come from asteroids or comets within our solar system. However, a small percentage comes from distant stars. There are no natural terrestrial sources for the iron-60 isotope contained therein; it originates exclusively as a result of supernova explosions or through the reactions of cosmic radiation with cosmic dust.
Antarctic snow travels around the world
The first evidence of the occurrence of iron-60 on Earth was discovered in deep-sea deposits by a TUM research team 20 years ago. Among the scientists on the team was Dr. Gunther Korschinek, who hypothesized that traces of stellar explosions could also be found in the pure, untouched Antarctic snow. In order to verify this assumption, Dr. Sepp Kipfstuhl from the Alfred Wegener Institute collected 500 kg of snow at the Kohnen Station, a container settlement in the Antarctic, and had it transported to Munich for analysis. There, a TUM team melted the snow and separated the meltwater from the solid components, which were processed at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) using various chemical methods, so that the iron needed for the subsequent analysis was present in the milligram range, and the samples could be returned to Munich.
Korschinek and Dominik Koll from the research area Nuclear, Particle and Astrophysics at TUM found five iron-60 atoms in the samples using the accelerator laboratory in Garching near Munich. "Our analyses allowed us to rule out cosmic radiation, nuclear weapons tests or reactor accidents as sources of the iron-60," states Koll. "As there are no natural sources for this radioactive isotope on Earth, we knew that the iron-60 must have come from a supernova."
Stardust from the interstellar neighborhood
The research team was able to make a relatively precise determination as to when the iron-60 has been deposited on Earth: The snow layer that was analyzed was not older than 20 years. Moreover, the iron isotope that was discovered did not seem to come from particularly distant stellar explosions, as the iron-60 dust would have dissipated too much throughout the universe if this had been the case. Based on the half-life of iron-60, any atoms originating from the formation of the Earth would have completely decayed by now. Koll therefore assumes that the iron-60 in the Antarctic snow originates from the interstellar neighborhood, for example from an accumulation of gas clouds in which our solar system is currently located.
"Our solar system entered one of these clouds approximately 40,000 years ago," says Korschinek, "and will exit it in a few thousand years. If the gas cloud hypothesis is correct, then material from ice cores older than 40,000 years would not contain interstellar iron-60," adds Koll. "This would enable us to verify the transition of the solar system into the gas cloud - that would be a groundbreaking discovery for researchers working on the environment of the solar system.
Publications:
D. Koll, G. Korschinek, T. Faestermann, J. M. Gรณmez-Guzmรกn, S. Kipfstuhl, S. Merchel, J. M. Welch: Interstellar 60Fe in Antarctica. In: Physical Review Letters 123, 072701. August 2019.
DOI: 10.1103/PhysRevLett.123.072701
And waaaay down the bottom they attribute this *stardust* to an hypothesis. Where are the other examples of iron 60 scattered around Antarctica? or evenly distributed around the Earth for if it came from a supernova then surely
to christiron 60 would be evenly distributed around this devil's playground we call Earth and not found in some remote part of the plane t where no private person is allowed to go without the threat of execution and just a few miles from where the all spark fell to Earth as well as numerous UFO's, some of which contain man eating aliens that crashed millions of years ago only to be dug up by someone who miraculously stumbled upon it like a needle in a 500 Kg sample of snow out of the entirety of snow in Antarctica. Why didn't they just go to Siberia to make this shit up, it would have cost far less. Oh, and the entire atmosphere has been sullied and that includes the air they breathe all the way down (across) in Antarctica.Q. If an Alien landed their UFO anywhere in the world, Antarctica included, what do you think the first thing they would say is?
A. Pong, This place stinks!
Radioactive isotopes from 6 decades of open air nuclear testing and mishaps... including the PM-3A reactor accident at McMurdo station absolutely has infiltrated Antarctica's purported pristine environment.
Rant over, my apologies... I promise it will never happen again, like
suicidesexecutionsstageddeath in custody of accused pedophiles in groundbreaking ...child prostitution.... okay, okay.. I'm a terrible lier, but I can't be held responsible for my actions!