Red Shift & Big Bang

🚀 The Universe is Running Away

Figure 1: Galaxies at increasing distances — notice how the colour shifts from blue-white (nearby) to red (far away). This is red-shift, caused by the expansion of space stretching the wavelength of the light reaching us.

In 1929, the American astronomer Edwin Hubble made a discovery that overturned everything scientists thought they knew about the universe. By carefully analysing the light from distant galaxies, he found that nearly every galaxy is moving away from us — and that the further away a galaxy is, the faster it is receding. The universe is not static. It is expanding.

Think of it like a balloon being inflated. Draw dots on the surface of the balloon to represent galaxies. As the balloon inflates, every dot moves away from every other dot — and dots that were further apart to begin with move apart faster. No single dot is at the centre; the expansion is happening everywhere, in all directions.

If you run this expansion backwards in time — like rewinding a film — all the galaxies come together at a single point. Go back far enough, about 13.8 billion years, and everything in the observable universe was compressed into an unimaginably hot, dense state. Then it expanded rapidly. This was the Big Bang — not an explosion in space, but the creation of space itself.