The Fermi telescope, seeing the sky in gamma rays, has given us our best view yet of the high energy Universe. A world where bizarre events give out so much energy that it’s difficult for us to fully appreciate their scale.
But the Fermi telescope is pretty interesting in its own right. This is effectively a Fermi long exposure, showing the pattern traced by the Vela pulsar in Fermi’s field of view. The Vela pulsar is the brightest continuous gamma ray source in the sky. A tiny neutron star born in a supernova, incredibly hot and spinning on its axis once every 11 seconds. This image shows Fermi’s view for about 2 years, between 2008 and 2010, and the “star trails” which the pulsar made.
It completes an orbit of Earth every 95 minutes and slowly rocks back and forth as it orbits so it can see the whole sky. On top of that, it needs to roll to keep its solar panels pointed towards the sunlight that powers it. Finally, its orbit doesn’t stay the same. It precesses – effectively, the orbital path itself rotates – completing a full rotation every 54 days. All of these rocks and rolls are what gives Fermi such an unusual view of the sky.
With a tip of the hat to apod!