Did the Big Bang Really Happen? | Cosmic Inflation | How the Universe Works

Did the Big Bang Really Happen | How the Universe Works New discoveries cause astronomers to question if the Big Bang really happened, and using the latest science, they investigate if it wasn't just the start of the universe but many mysterious multiverses. Is cosmic inflation true? Inflation is now a built-in piece of our standard story of cosmic evolution. But it's still controversial. What happens during cosmic inflation? Cosmic inflation is the idea that the nascent universe passes through a phase of exponential expansion that was driven by a negative-pressure vacuum energy density that acts, in high energies, with repulsive gravity. As a direct consequence of this expansion, all of the observable universe originated in a small causally-connected region. How does inflation solve the flatness problem? Inflation solves the flatness problem by exponentially growing the initial tiny universe out of any curvature, in the same way that the surface of a sphere becomes flatter as it becomes larger. For example, Earth appears flat although it is really a very large sphere. How does inflation solve the horizon problem (why is the universe homogeneous and isotropic)? The horizon problem is solved by inflation because regions that appear to be isolated from each other were in contact with each other before the inflation period. They came into equilibrium before inflation expanded them far away from each other. Does cosmic inflation predict a multiverse? The theory of cosmic inflation predicts a multiverse: an enormous number of universes. We cannot detect these other universes, but their existence may not be avoidable in the context of inflation. Why did cosmic inflation stop? Some physicists believe that the decay of the Higgs field stopped inflation. Why is cosmic inflation faster than light? In an inflationary universe, any two particles, beyond a tiny fraction of a second, will see the other one recede from them at speeds appearing to be faster-than-light. But the reason for this isn't because the particles themselves are moving, but rather because the space between them is expanding. Why is cosmic inflation necessary? Because the accelerating expansion of space stretches out any initial variations in density or temperature to very large length scales, an essential feature of inflation is that it smooths out inhomogeneities and anisotropies, and reduces the curvature of space.