The Orian nebula(M42) is the brightest nebula in the sky and it occupying an area twice the diameter of the full moon. It can be viewed with naked eye. Most nebulas are of vast sizes. Some are hundred of light years in diameter. Many nebulas are visible due to fluorescence caused by embedded hot stars. Some nebulas are variable stars. Watch this video for more info –
The Super massive black hole at the core of supergiant elliptical galaxy Messier 87, with a mass 7 billion times the sun as depicted in the first image released by Event Horizon telescope.
Visible are the crescent-Shaped emission ring and central shadow, Which are gravitationally magnified views of the black hole’s photon ring and the photon capture zone of its event horizon. The crescent shape arises from the black hole’s rotation and relativistic beaming, the shadow is about 2.6 times the diameter of the event horizon. There are three types of black holes. Stellar black holes, Super massive black holes, primordial black holes.A simulated view of a black hole infront of the large magellanic cloud. M87’s Black hole is 26000 light years far from the earth.