Titanium in Cosmic Rays
In the stream of cosmic rays, particles flying toward us from the depths of the Galaxy, titanium is rare. Its nuclei are almost indistinguishable from iron: both are heavy, and both leave similar tracks in detectors.
Cosmic nuclei reveal their energies
High above the Antarctic ice sheet, a balloon with a detector floated for twenty days. It caught tiny particles that had been traveling toward us for millions of years from distant stellar explosions. Now scientists have sorted through the catch and reported how much energy the protons and nuclei of different elements carried.
Extra Electrons in Cosmic Rays
High above Antarctica, a balloon carried an instrument that caught electrons from space. These particles come from distant stellar explosions and other powerful events. The instrument measured their energy, like the force of an impact. And in one energy range, there were more impacts than calculations predicted.
Cosmic Surprise: Iron Behaves Differently
In the stream of charged particles flying toward us from the depths of the Galaxy, iron turned out to be the odd one out. The ATIC-2 instrument, lifted on a balloon over Antarctica, compared how the fraction of nuclei from sulfur to chromium relative to iron changes with energy.