Uranus Hot Spot
This photo of Uranus was taken by the Gemini North telescope atop Mauna Kea. It shows a mysterious spot ten times brighter than the planetary background. Astronomer Heidi Hammel appealed on her Facebook page for others to confirm this observation. Hopefully the Hubble Space Telescope can be used to get better images.
The spot is interpreted as an eruption of methane gas high in Uranus' atmosphere. Heat and methane indicate an internal source. Uranus was thought to emit very little heat compared to Jupiter or Saturn. The planet's spin axis in tilted nearly sideways from the solar system plane, so one hemisphere can be warmed uniformly for 42 years. How such a concentrated hot spot could appear is a complete mystery.
If Uranus formed around a Black Hole, the singularity would provide a source of internal heat nearly indefinitely. Radiation would erupt in jets from the Black Hole, following magnetic field lines. Uranus' magnetic poles are tilted 59 degrees from the spin axis, indicating the direction of the Black Hole's spin axis. Because of this tilt, heat plumes from the jets do not erupt at the poles but are carried along in the atmosphere to erupt in the lower latitudes.
This hot spot occurs at 22.5 degrees North, roughly at rest with the planetary interior. This could be more than just an asteroid impact. Source of the hot spot must be something deep inside Uranus. The interior of a giant planet like Uranus is a good place to find a Black Hole.