Detection at t=0: looking at the beginning of time

Detection at t=0: looking at the very beginning of time, we saw the echoes of the Bang imprinted across the sky.

We’ve all heard the big news yesterday. Scientists spotted the gravitational ripples that left marks in the distribution of energy, which is strong evidence for inflation, but how did they do it?

Polarization means the electric vector of the photon oscillates in a specific direction. B-mode polarization is a pattern in the CMB radiation that can be broken into two components. One, a curl-free, gradient-only component, the E-mode, was first seen in 2002 by the Degree Angular Scale Interferometer (DASI). The second component is gradient-free, curl only, and is known as the B-mode. Cosmologists predict two types of B-modes, the first generated during cosmic inflation, and the second generated by gravitational lensing later, due to light encountering matter on its way. Gravitational waves squeeze space as they travel, and this squeezing produces a distinct pattern in the cosmic microwave background. GWs have a handedness or chirality, much like light waves, and can have left- and right-handed polarizations which makes them very recognizable.