In A Nutshell. Hemp and marijuana both come from the same species of plantâcannabis. However, hemp is generally harvested from a subspecies of the Cannabis genus, which, unlike marijuana, has virtually no psychoactive properties. Hemp varieties are grown for their seed, oil, and fiber, whereas marijuana is grown for medicinal, recreational, and spiritual purposes.
Theyâre the correct shape, theyâre coming in at just the right angle, and theyâre covered in an appropriate skinâ¦. Space may be the final frontier, but coming back to Earth after a visit to a planetary neighbor, or even a high orbit, can be perilous. As anyone whoâs seen the movies The Right Stuff and Apollo 13 knows, a spacecraft must reenter Earthâs atmosphere at a precise angle to avoid burning up or skipping back out into space. Well before the space program, astronomers were aware that meteorites burned up when they fell into our atmosphere. The reason, notes Allie Anderson, a graduate student in Aeronautics and Astronautics, is friction with air molecules (remember, thereâs no air in outer space).
Quick Answer. Earthâs atmosphere protects life on the surface by filtering deadly ultraviolet radiation, destroying most meteors that pass through it and retaining heat. The atmosphere also provides oxygen to humans and carbon dioxide to plants. The atmosphere consists of five layers and is approximately 60 miles thick. The layer closest to the surface is called the troposphere, and it provides the majority of the planetâs oxygen. This layer is also responsible for weather, including rain, which protects Earth's inhabitants from drought and starvation.