In the centre of our galaxy lies an X-ray source, the intensity of which can fluctuate wildly by the minute. Is this radiation emitted from matter that is falling into a super-massive black hole?
The galaxy NGC 5128 is located 11 million light years from earth. What is the source of the 10,000 light-year-long jet that emanates from the centre of the galaxy?
A supernova explosion observed in 1054 AD created a neutron star in the Crab nebula. It has a diameter of only 20-30 km, has about the same mass as the sun and rotates 30 times per second! Hot gas is pulled towards the neutron star and emits X-rays.
The remnants of the supernova that Tycho Brahe observed in 1572 – still a scorching 10 million °C hot.
Eta Carinae is a massive and unstable star with strong stellar winds. Perhaps a future supernova?