It Wasn't an Explosion
The Big Bang is not a blast into empty space. It means space itself was expanding everywhere from an ultra-hot, ultra-dense beginning.Big Bang: What It Really Means
The Universe Left a Glow
About 380,000 years later, the universe cooled enough for atoms to form. That made space clear enough for light to travel freely, and that leftover light still fills the sky today as the cosmic microwave background.Big Bang: What It Really Means
