Sobehrad's First Semester Earth Science Exam 2023-2024 | Latest Update 2024 | 34

composition of the atmosphere {Ans: 78% nitrogen, 21% oxygen, 1% other}redshift {Ans: as objects move away from Earth, light given off is stretched; red is the longest wavelength of light so the light "shifts" toward red as it stretches out}cosmic background radiation {Ans: the early univer(se was once extremely hot; as the universe cooled down after the Big Bang, the radiation began to move and stretch into longer wavelengths that can still be seen today (interference)}where does weather occur {Ans: troposphere}ratio of hydrogen to helium {Ans: by mass, the universe consists of mostly hydrogen (75%) and helium (25%)}birth of a star {Ans: stars form when regions of dust and gas in the galaxy collapse due to gravity and start to spin; the star is born when nuclear fusion in the core of the star begins}3 pieces of evidence for the Big Bang {Ans: hydrogen and helium are everywhere in equal proportions; cosmic background radiation; red shift}electromagnetic spectrum {Ans: Radiation that travels as transverse waves; includes radio waves, microwaves, infrared waves, visible light, xrays, ultraviolet waves, and gamma waves.}equinox and solstice {Ans: in spring and fall the equinoxes occur and are the