The Universe Stars and Galaxies Worksheets

Further observational improvements led to the realization that the Sun is one of hundreds of billions of stars in the Milky Way, which is one of at least hundreds of billions of galaxies in the Universe. Many of the stars in our galaxy have planets. At the largest scale, galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center....

Space Ship Silhouette

On a sub-orbital spaceflight, a space vehicle enters space and then returns to the surface, without having gained sufficient energy or velocity to make a full orbit of the Earth. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit (space...
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