Space

...Earlier this century, some very strong evidence arrived showing that there was a Universe before the Big Bang, demonstrating that the Big Bang wasn’t truly the start of it all...

...The differences between a Universe that began with a hot Big Bang and a Universe that had an inflationary phase that precedes and sets up the hot Big Bang are subtle, but tremendously important...

...in a Universe that underwent a period of inflation prior to the start of the hot Big Bang, we’d expect there to be density fluctuations on all scales, including on scales larger than the speed of light, which could have allowed a signal to travel since the start of the hot Big Bang...

Although later fluctuations superimpose themselves atop the older, earlier, larger-scale fluctuations, inflation allows us to start the Universe off with ultra-large-scale fluctuations that shouldn’t exist in the Universe if it began with a Big Bang singularity without inflation.

...At any moment in the Universe’s history, there’s a limit to how far a signal that’s been traveling at the speed of light since the start of the hot Big Bang could’ve traveled, and that scale sets what’s known as the cosmic horizon...scales that are greater than the horizon, known as super-horizon scales, are beyond the limit of what could’ve been caused by physical signals generated at or since the start of the hot Big Bang.

...When we look at the final (2018-era) Planck TE cross-correlation data, below, the results are breathtaking...As you can clearly see, there can be no doubt that there truly are super-horizon fluctuations within the Universe, as the significance of this signal is overwhelming. The fact that we see super-horizon fluctuations, and that we see them not merely from reionization but as they are predicted to exist from inflation, is a slam dunk: the non-inflationary, singular Big Bang model does not match up with the Universe we observe.