7/ So, how do we know the universe is expanding?
1. Galaxies are moving away (Hubble’s law).
2. Light from galaxies is redshifted.
3. The CMB confirms the universe once was much hotter and denser.
1. Galaxies are moving away (Hubble’s law).
2. Light from galaxies is redshifted.
3. The CMB confirms the universe once was much hotter and denser.
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If the universe is expanding, it must have been smaller and denser in the past. By tracing this backward, scientists concluded it all began from a single point: the Big Bang.
Pictures below are all real from #JWB
#BigBang #Cosmology #Space