A Coronal Mass Ejection (CME) from the Sun frames Mercury, as observed by the SOlar Heliospheric Observatory (SOHO) on 13 August 2014.
The shaded blue disc surrounding the Sun at the centre is a mask in SOHO’s LASCO instrument that blots out direct sunlight to allow study of the details in the Sun’s corona.
More about SOHO: http://sci.esa.int/soho With thanks to @SungrazerComets for posting on Twitter.