Tag: tracer

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,...

Astroarcheology – The Oldest Stars

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A few hundred million years after the big bang, the first stars formed.  We aren’t exactly sure how, but we do know that they contained Hydrogen, Helium, and a little bit of Lithium.  These were the only elements in the entire universe at the time.  Within these first stars, the fusion of heavier elements began.  Oxygen, Nitrogen, Carbon, Iron, and all the other elements that make up everything we know formed Billions of years ago in these first stars and in their progenitors.  It was a slow process to produce these elements and seed them throughout the cosmos, but over...