 Hello everyone and welcome to our universe. Today we'll be talking about the Crab Nebula. The Crab Nebula is also known as Messier 1, or M1, and it's basically an expanding supernova remnant that has a tiny pulsar at the centre. Messier 1 is located in the northern constellation of Taurus, also known as the Bull. It has an apparent magnitude of 8.4 and can be seen with binoculars, with good viewing conditions. The Crab Nebula is the only supernova remnant that is listed in the Messier catalogue, and is probably the most famous object of its kind in the night sky. The Nebula has a luminosity of 75,000 times that of our Sun, and it lies at a distance of 6,500 light-years from Earth. The Crab Nebula is a result of a supernova explosion, also known as SN-1054, basically because it was observed by Chinese astronomers in 1054 AD. Makes sense, right? Messier 1 is about 11 light-years in diameter, and it also expands at a rate of 1,500 km per second to this day. The supernova remnant at its centre contains a pulsar called the Crab Pulsar. This is a rapidly expanding neutron star that spins at a rate of over 30 times per second. The pulsar is categorised as PSR0531 plus 21. It emits radiation in optical, radio, ultraviolet, X-rays and gamma-ray wavelengths. X-ray emissions of the supernova were actually detected in 1963. This explosion of the supernova and the star itself has produced a large shell of fragments and filaments that has continued to expand to the present day, but eventually it will disappear and disperse into the space around it. The nebula's filaments contain ionised gas, and this is responsible for the glow within the nebula. The electrons found in this gas move very close to the speed of light. This emits radiation and this makes it very visible in radio wavelengths. The filaments of the Crab Nebula are very similar to a star's atmosphere, because they mainly contain hydrogen and helium, but they also contain other elements, including oxygen, carbon, iron, nitrogen, sulfur and neon. The Crab Nebula was discovered by an English astronomer called John Beavis in 1731, but it was actually Charles Messier that discovered it independently in 1758 because he was actually looking for a bright comet. This bright comet was actually Halley's Comet that was predicted to return that year, but when he observed it, he noticed that it wasn't moving and therefore concluded that it wasn't a comet at all. The Crab Nebula was named after William Parsons because he made a drawing of the object in 1844, and it's basically called the Crab Nebula because it sort of resembles a crab in the drawing. Well, sort of. It is located one degree northwest of the bright star Zeta Tauri. If you try and find the constellation of Taurus, the best star to find is Aldebaran. If you can't find Aldebaran, you can easily find it by looking at the belt of Orion and kind of drawing an imaginary line from there to a red star. From Aldebaran, you just need to look at the V shape of the ball, and from this follow that onward and you'll find M1 in a basic straight line. The Crab Nebula also has a pulsar. This is about 17 to 18 miles across. It also emits pulses of optical, radio and x-ray radiation. It was one of the first pulsars ever to be discovered, and it provided evidence of the theory that pulsars formed in a supernova event. In 1967, the region around the star was actually identified as one of the brightest gamma ray sources in the night sky. The mass of the neutron star is 1.4 to 2 solar masses. And then, in 1968, the neutron star was observed for the first time. This helped astronomers understand the nature of a supernova remnant, and made it possible for them to verify the pulsar's basic properties. For example, its age, its spin, its luminosity and its orders of magnitude. So finally, we come to the supernova itself. This was first noticed with astronomers measured the structure itself, and came to the conclusion that it was moving and expanding. This would have been visible for approximately 23 days, and it would have been the brightest object in the night sky, second to only the moon, and was believed to be visible to the naked eye for over 600 days after its discovery. It is believed that the star that went supernova had a mass between 9 and 11 solar masses. The existence of this pulsar indicates that the nebula formed in a core-collapsing supernova. This basically happens when a massive star runs out of fuel and collapses in on itself. And from this, it explodes and creates the structure of the crab nebula. So, I hope that's given you a great insight into Messier 1, the crab nebula. Also, if you want to know any more about Messier 1, I'll put some links in the description below. And as always, if you've enjoyed the video, click the like button, and if you want to support the channel, click subscribe. Thank you for watching.