Final answer:
The Crab Nebula is a supernova remnant, rich in energy output and historical significance, observed since 1054 and known for its broad spectrum emissions.
Step-by-step explanation:
The Crab Nebula is a supernova remnant from an explosion observed in 1054. It is known for its significant energy output, glowing at a multitude of wavelengths, and containing a pulsar at its core. The nebula is a remarkable astronomical object due to its historical significance and continuous emissions of electromagnetic radiation across the spectrum, including visible light, X-rays, and infrared light. Measurements of the emitted light wavelengths have also allowed astronomers to identify certain ions present, such as S+ (with green filaments) and O²+ (with red filaments), providing insights into its composition.