One source of high-energy neutrinos is likely to be supernova remnants, such as the Crab Nebula.

ECONOMIST: Neutrino astronomy

The first is that not all supernova remnants (which are often visible as glowing nebulae, such as the Crab nebula) have pulsars inside them.

ECONOMIST: Pulsars

In a recent paper, Dr Jacobson argues that observations made of synchrotron radiation produced by the Crab nebula (the remnants of a supernova observed in 1054) limit the granularity of space.

ECONOMIST: Planck-scale physics

Because radiation from the Crab nebula is so energetic, the electrons that created it must have been travelling very close to the speed of light so close that the difference between the two speeds would bump up against Planck-scale graininess, and show up in the spectrum of the radiation.

ECONOMIST: Planck-scale physics