Astronomers measure spectra of stars in a galaxy. If they shift to blue, then the galaxy is drifting fast, and to red then the galaxy is drifting slowly. (Like the sound of the horn on the bus, we hear it loud when we are near the bus and soft when we are far away from it).
And they discovered that galaxies and celestial bodies are going away from each other, so they concluded that: In the past, all galaxies and celestial bodies stayed very near each other, so it must have been a bang that caused those galaxies and celestial bodies to go apart.
On the surface, that conclusion seems reasonable. However, it is still a naïve conclusion but at a high level. When science had not yet advanced, people thought that the Sun revolved around the Earth and with that simple thinking; people were not uncomfortable in a long time. Now with science’s advancement, people still make another naïve assumption that the universe was formed from the Big Bang.
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Source: Buddha Everywhere Fanpage
Link: https://goo.gl/WyoQXF
