(Top) B-mode polarization pattern observed by the BICEP2 telescope . The twisting pattern in the polarization of the cosmic microwave background (CMB) might originate from gravitational waves created by inflation in the very first moments of the universe’s expansion. The line segments display the magnitude and orientation of linear polarization at different spots of the sky. (Bottom) Power of CMB polarization modes decomposed into spherical harmonic modes (l). Higher l modes correspond to smaller angular scales of the sky. The BICEP signal is above expected backgrounds (solid line) for l less than about 150 and follows well the predicted shape of an inflationary signal (dashed line). Note that dust foreground effects are poorly constrained at the moment and could be significant.