This image shows the x-ray sky from another perspective. The data was collected from observations of “soft” x-ray emissions (so called because they are toward the lower end of the energy spectrum) made by sounding rockets. Sounding rockets carry astronomical instruments into space and then return after spending a few of minutes above the Earth’s atmos- phere. Although modern astro- nomical satellites permit much longer and more thorough observa- tions, sounding rockets were at one time the only way to conduct space astronomy. 
    Curiously, the intensity of x-ray emission increases toward the galactic poles (the points directly above the center of the galactic disk). It is not clear what causes this