In this section you read about the different forms of radiation that are used to view the Crab Nebula. Below are facts based on the Crab Nebula and General Information, Radio Astronomy, Optical Astronomy, Ultraviolet Astronomy, and X-ray Astronomy. If you think that the fact belongs with the General Information, place a G in the blank. If you think that the fact belongs with the Radio Astronomy, place an R in the blank. If you think that the fact belongs with the Optical Astronomy, place an O in the blank. If you think that the fact belongs with the Ultraviolet Astronomy, place a U in the blank. If you think that the fact belongs with the X-ray Astronomy, place an X in the blank. Then check your answers.

1. The Crab Nebula was first seen in 1054, by Chinese astronomers and members of the Anasazi tribe, who recorded the appearance of a new star.
2. This shows two colors within the Nebula, a blue core with red filaments surrounding it.
3. The "hot" electrons needed for this type of radiation are found only in the center of the pulsar. Thus, the nebula appears small and condensed.
4. The Crab Nebula is the remains of a star which suffered a supernova explosion.
5. Scientists use this type of radiation to observe the expansion of the nebula over the course of decades.
6. This image was false colored to show the intensity of the waves coming from electrons spiraling around in the nebula.
7. This type of Astronomy reveals a condensed core near the center of the pulsating neutron star.
8. We see flashes from the neutron star when one of its magnetic poles is pointed towards the Earth.
9. This shows that the nebula pulses at about 60 times a second.
10. This type of radiation shows that cooler electrons extend out beyond the central pulsar.