Researched
Expansion & Big Bang
Lemaître and Hubble show that the universe expands (1927/1929); the cosmic microwave background (1964) confirms a hot beginning.
Open in the interactive tree →Friedmann and Lemaître derived an expanding universe from general relativity, and Hubble measured in 1929 that galaxies recede faster the farther away they are. Penzias and Wilson found the afterglow of the Big Bang in 1964, and the Planck satellite later fixed the age of the universe at 13.8 billion years. Inflation (Guth, 1981) explains why the universe is so uniform.
Prerequisites
- The telescope1608
- Spectroscopy1859Galaxy redshifts are measured from shifted spectral lines
- Theory of Relativity1905
- Cepheid distance yardstick1912Cepheid distances showed that galaxies lie outside the Milky Way
- Other Galaxies (Hubble)1924Hubble's galaxy distances led to the expanding universe