An example of this structure is the first item in the Messier (MESS-ee-ey) catalog.
Kant and Laplace's hypothesis for the mechanism of solar system formation is named for this kind of structure. An example of this structure is the first item in the Messier (MESS-ee-ey) catalog. One of these in Cygnus is named for the fact that it (*) resembles North America. Types include emission, reflection, and planetary and one found in Orion takes its name from its shape, a horsehead. For 10 points, give this term for a cloud of interstellar dust, examples of which include the "crab."
Kant and Laplace's hypothesis for the mechanism of solar system formation is named for this kind of structure.
{nebulas} [or {nebulae}]