In 1910 Vesto Slipher was the first person to observe shifts in spectral lines in galaxies. What he had discovered was the galactic redshifts. A galactic redshift is a displacement of spectral lines toward longer wavelengths. What Slipher specifically observed was that the spectral lines of many nebulas exhibited a red shift that indicated motion away from planet earth.
Around 1912 Carl Wilhelm Wirtz like Vesto Slipher observed a systematic redshift of nebulae. While observing the redshift he came to the conclusion that relative to the present location of the solar system the spiral nebulae is moving away from the solar system. He later discovered that it is moving away from the solar system at 656 kilometers per second. This provided observational evidence that the universe was expanding.
In 1916 Albert Einstein published his Theory of General relativity. The General relativity Theory states that gravitation arises from the curvature of space and time. It also said that the universe was either contracting or expanding. Today the theory is used to describe gravitation in physics. Einstein’s theory was influential to the development of the Big Bang theory because it created the cosmological constant.
Alexander Friedmann used Einstein’s theory in order to come up with his own findings. He applied general relativity to cosmology without using the cosmological constant. He found solutions to field equations that created the preliminary work of the Big Bang Theory. His solutions created the...