Publish Date: 
May 22, 2016


GEMS Mission Image

The Gravity and Extreme Magnetism Small Explorer (GEMS) did not pass its confirmation review in 2012 and never moved into the development phase.

GEMS would have used an X-ray telescope to measure the polarization of the X-rays coming from the vicinity of compact objects in the universe: black holes and neutron stars and it would have also studied the remnants of massive stars which have exploded as supernovae. Few polarization measurements have been made in X-ray astronomy since the 1970’s so GEMS was expected to break new ground. The polarization depends, in part, on the X-ray scattering in the accretion disk around the compact object in a binary star system, so GEMS would have helped to constrain the geometry in such systems. GEMS might also have helped to constrain the shape of space that has been distorted by a spinning black hole's gravity, and probe the structure and effects of the formidable magnetic field around magnetars, dead stars with magnetic fields trillions of times stronger than Earth's.

GEMS would have helped to explain:

  • How spinning black holes affect space-time and matter as it is drawn in and compressed by strong gravitational fields.
  • What happens in the super strong magnetic fields near pulsars and magnetars.
  • How cosmic rays are accelerated by shocks in supernova remnants.

Last Updated Date: May 28, 2015

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Full Name: 
Gravity and Extreme Magnetism Small Explorer