The Astronomy Book

159 Studying nebulae Slipher’s initial work and research were directed at the planets, but from 1912, at Lowell’s request, he be ...

160 asserted that “we have at the present no other interpretation for it. We may conclude that the Andromeda nebula is approachi ...

161 it seems to me, gains favor in the present observations.” Slipher was echoing Kant’s suggestion that some nebulae, in partic ...

162 STARS ARE DOMINATED BY HYDROGEN AND HELIUM STELLAR COMPOSITION IN CONTEXT KEY ASTRONOMER Cecilia Payne-Gaposchkin (1900 –197 ...

163 Hydrogen and helium together make up 98 percent of all of the matter throughout the galaxy that is made of atoms (this omits ...

164 OUR GALAXY IS ROTATING THE SHAPE OF THE MILKY WAY IN CONTEXT KEY ASTRONOMER Bertil Lindblad (1895 –1965) BEFORE 1904 Jacobus ...

165 See also: Spiral galaxies 156–61 ■ Beyond the Milky Way 172–77 ■ The Oort cloud 206 ■ Dark matter 268–71 ATOMS, STARS, AND G ...

166 A SLOW PROCESS OF ANNIHILATION OF MATTER NUCLEAR FUSION WITHIN STARS IN CONTEXT KEY ASTRONOMER Arthur Eddington (1882–194 4) ...

167 See also: The theory of relativity 146–53 ■ Stellar composition 162–63 ■ Energy generation 182–83 ■ Nucleosynthesis 198–99 A ...

168 A DAY WITHOUT YESTERDAY HE BIRTH OF THE UNIVERSET T he idea that the universe originated from a tiny object in the form of a ...

169 See also: Gravitational theory 66–73 ■ The theory of relativity 146–53 ■ Spiral galaxies 156–61 ■ Beyond the Milky Way 172–7 ...

170 universe.” Einstein first called his work “suspicious,” but six months later acknowledged that his results were correct. How ...

171 Lemaître’s model of a universe expanding from an initial extremely dense concentration of mass and energy is today called th ...

THE UNIVERSE IS EXPANDING IN ALL DIRECTIONS BEYOND THE MILKY WAY ...

THE UNIVERSE IS EXPANDING IN ALL DIRECTIONS BEYOND THE MILKY WAY ...

174 I n the early 1920s, American astronomer Edwin Hubble provided proof of the true size of the universe. Working at the Mount ...

175 at enormous speeds—speeds far too high for them to be contained within the Milky Way. Hubble set out to see whether there wa ...

176 published in a journal called Proceedings of the National Academy of Science in 1929. It contained a straight-line graph tha ...

177 called the “K-factor.” The gradient is described mathematically by a value now known as the Hubble Constant (H 0 ). This imp ...

178 See also: Discovering white dwarfs 141 ■ Nuclear fusion within stars 166–67 ■ Supernovae 180–81 I n 1930, a young Indian stu ...