National Museum of Natural History in the context of "Bureau of American Ethnology"

The Great Debate, also called the Shapley–Curtis Debate, was held on 26 April 1920 at the U.S. National Museum in Washington, D.C. between the astronomers Harlow Shapley and Heber Curtis. It concerned the nature of so-called spiral nebulae and the size of the universe. Shapley believed that these nebulae were relatively small and lay within the outskirts of the Milky Way Galaxy (then thought to be the center or entirety of the universe), while Curtis held that they were in fact independent galaxies, implying that they were exceedingly large and distant. A year later the two sides of the debate were presented and expanded on in independent technical papers under the title "The Scale of the Universe".

The National Anthropological Archives is the third largest archive in the Smithsonian Institution and a sister archive to the Human Studies Film Archive. The collection documents the history of anthropology and the world's peoples and cultures, and is used in indigenous language revitalization. It is located in the Smithsonian's Museum Support Center in Suitland, Maryland, and is part of the Department of Anthropology at the National Museum of Natural History.

Size is an important aspect of dinosaur paleontology, of interest to both the general public and professional scientists. Dinosaurs show some of the most extreme variations in size of any land animal group, ranging from tiny hummingbirds, which can weigh as little as two grams, to the extinct titanosaurs, such as Argentinosaurus and Bruhathkayosaurus which could weigh as much as 50–130 t (55–143 short tons).

The latest evidence suggests that dinosaurs' average size varied through the Triassic, early Jurassic, late Jurassic and Cretaceous periods, and dinosaurs probably only became widespread during the early or mid Jurassic. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100–1,000 kg (220–2,200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the range of 10–100 kg (22–220 lb). The mode of Mesozoic dinosaur body masses is between one and ten metric tonnes. This contrasts sharply with the size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb).

The Human Studies Film Archives (HSFA) is a sister archive to the National Anthropological Archives within the Smithsonian's National Museum of Natural History. HSFA preserves and provides access to ethnographic films and anthropological moving image materials. It is located at the Smithsonian Museum Support Center in Suitland, Maryland.