Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Radius values (data points) from the X-rays (X) to the extreme ultraviolet (EUV), ultraviolet and optical (V) band. The approximate full-width-half-maximum of each channel16,24 is marked (horizontal error bar). Predictions from a model8 at SZA=90° (blue dashed line) is shown for comparison.