Tag: decay

The Nearby Supernova Revealed

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Remember last week when I was talking about the evidence for some ancient-but-astronomically-recent supernovae? It turns out there is other evidence! Evidence that has helped scientists narrow down the potential source locations. Data from the Cosmic Ray Isotope Spectrometer (CRIS), an instrument aboard NASA’s Advanced Composition Explorer (ACE) spacecraft, has helped us figure out where the recent supernovae might have come from.  CRIS measures what we call cosmic rays, atomic nuclei that have been accelerated across the galaxy at close to the speed of light.  CRIS has been around for a while, and through 17 years of cosmic ray observations,...

Multiple Ancient Supernovae

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If a supernova were to go off somewhere in our galaxy, the minimum safe distance for Earthbound life would be about 50 light years.  Any closer than that, and we would experience an intense blast of high energy radiation and an eventual shower of radioactive particles.  It would be like nuclear bombs were set off all around the Earth, causing little destruction but a lot of radioactive fallout.  Supernovae are incredibly powerful to be able to cause such damage at 50 light years, but even at larger distances, we can see evidence of their effects here on Earth. A team of...