China was the world's leading ocean going nation by the eleventh century- their shipwrights had been building large sea worthy junks for decades. Some were three hundred feet long with a capacity of over a thousand tons and capable of holding five hundred to one thousand people. This was the time of the Sung Dynasty and the Chinese had made major advances in their knowledge of geography, mapmaking and astronomy. They had invented the compass which radically improved their ability to navigate- every ship carried one along with highly accurate marine charts, tide schedules and precision star maps. So, the appearance of a bright new star, four times as brilliant as Venus, caught the immediate attention of the general population- that it remained visible in broad daylight for almost a month and was seen in the night sky for almost two years made it all the more fantastic!
What they saw and recorded for posterity on July 4, 1054 was a rare, near-by supernova- the death of a star in the constellation of Taurus which had exhausted its nuclear fuel, could no longer support it's own enormous weight and therefore imploded. The internal shock from the inward rushing material was sufficient to tear the star into shreds and left only it's rapidly spinning central core enshrouded by an ever expanding cloud filled with fantastic hydrogen filaments, dust and other material from the it's outer layers.
The new star was also noted by the Japanese and native-American Anastazi Indians. Interestingly, the Europeans did not pay enough attention to make any note that modern researchers have been able to locate.
We now recognize the remains of this event, almost one thousand years later, as the Crab Nebula or M1, as designated by the famous French comet-hunter, Charles Messier.
This picture represents 24 hours of exposure with a 20 inch telescope located high in the south-central mountains of New Mexico, USA. It reveals the Crab Nebula as it would appear to our eyes if they were the size of wagon wheels!
The nebula is expanding at a rate of about 2,000 kilometers per second- the cloud has grown to over ten light years in diameter since the time of its explosion! At the center of the cloud are a pair of small, equally bright stars- the star on the right is the source of the explosion! It's incredibly dense, essentially comprised of atomic neutrons and is estimated to weigh something like several mountains per teaspoon full! It's also spinning at about 30 times per second! This rapid motion creates a large magnetic field that causes the blue-white gas and dust filling the interior to rotate around the exploded star in a donut shaped torus with jets spitting laterally from the center.
Protruding up from the red mass of filaments, is a towering dark-teal jet of material that was first seen in 1970 through long-exposure photographs due to its extreme faintness. Interestingly, this remarkable jet has been overlooked by astrophotographers for decades until now- you are also seeing it in its natural color for the first time.