At http://phys.org/print395482259.html … when the Venus transit took place (Venus passing between Earth and the Sun) opportunities existed to get a better view of the planet (Venus). In June of 2012 scientists discovered a discrepancy (which they at first thought might be attributed to a technical fault in their telescope). X-rays and ultra-violet emissions were coming from the dark side of Venus. Naturally, this intrigued them and they checked out the details with data from another telescope. the Chandra X-ray Observatory. This showed similar emissions but coming from the sunlit side of Venus. It seems that Venus has an unexplained source of non-visible light coming from somewhere in its atmosphere.
Looking for where that might be they realised it might be as a result of scattering or re-emissions from the wake of Venus (probably as a result of the long magnetotail that is regularly buffeted by the solar wind which can reach as far as earth's orbit). The emissions, in other words, could be re-emitted radiation by the planet that derives from the magnetotail (rather than from the planet itself). The solar wind interacts with the magnetotail and is scattered along the length – and only appears to be generated by Venus. It's quite a clever explanation – and what relation have x-rays with an origin in the solar wind (and therefore the sun itself) have with x-rays coming from so called black holes emitted from the centre of galaxies.