Along with the brown bear, it is one of only two of the eight modern bear species not considered globally threatened with extinction by the IUCN. American black bears often mark trees using their teeth and claws as a form of communication with other bears, a behavior common to many species of bears.
Planetary nebulae are astronomical objects made up primarily of gaseous materials. They are extended in size and fuzzy in appearance, and generally show some degree of symmetry. The nebula is illuminated by a central star, which sometimes is too faint to be seen.
A nebula (Latin for cloud; pl. nebulae, nebulae, nebulÃ¦ or) nebulas is an interstellar cloud of, dust, hydrogen helium and other ionized. Gases, originally nebula was a name for any diffuse astronomical, object including galaxies beyond The Milky. wayne of the best examples of this is the Crab Nebula, in Taurus. The supernova event was recorded in the year 1054 and is labelled SN 1054. The compact object that was created after the explosion lies in the center of the Crab Nebula and is a neutron star. Other nebulae may form as planetary nebulae.