Amplitude of the solar cycle in irradiance variations as a function of wavelength in the 168–210 nm (panel a), 210–400 nm (panel b), 400–700 nm (panel c), and 700–2430 nm (panel d) spectral bands. The amplitudes for the solar age of 1 Gyr (black), 2 Gyr (orange), 2.8 Gyr (red), and 4.6 Gyr (green) are shown. The horizontal black line shows the Sun at the zero level of the variability.