what are 3 pieces of evidence that support the big bang theory
1. Cosmic Microwave Background Radiation: One major piece of evidence for the Big Bang theory is the detection of the cosmic microwave background radiation (CMB), which is found uniformly throughout the entire universe. The CMB consists of faint radio waves that represent the remnants of the early universe, reaching us from about 380,000 years after the Big Bang. Its discovery in 1965 provided strong support for the idea that the universe underwent a rapid expansion from an extremely hot and dense state.
2. Redshift and Hubble's Law: Another evidence supporting the Big Bang theory is the observation of the redshift in the light from distant galaxies. When astronomers analyze the light spectrum from these galaxies, they notice that the light is shifted towards longer wavelengths, indicating that the galaxies are moving away from us. This is similar to how the pitch of a siren changes as it moves away from an observer. Edwin Hubble's observations in the 1920s showed that the farther a galaxy is, the faster it is moving away. This led to the development of Hubble's Law, which implies an expanding universe and lends support to the idea of the Big Bang.
3. Abundance of Light Elements: The relative abundance of light elements provides another line of evidence for the Big Bang theory. According to the theory, during the early stages of the universe, there was a rapid expansion and cooling. As the temperature decreased, protons and neutrons combined to form atomic nuclei, a process called nucleosynthesis. The predictions of this process match the observed isotopic abundances of light elements, such as hydrogen, helium, and lithium in the universe. This alignment between theoretical predictions and empirical observations provides strong support for the idea of a primordial explosion like the Big Bang.