Rings of Rhea dips bear some similarity to the method by which the rings of Uranus were discovered in 1977. The slight deviations from absolute symmetry may be due to "a modest tilt to the local magnetic field" or "common plasma flow deviations" rather than to asymmetry of the rings themselves, which may be circular. Not all scientists are convinced that the observed signatures are caused by a ring system. No rings have been seen in images, which puts a very low limit on dust-sized particles. Furthermore, a ring of boulders would be expected to generate dust that would likely have been seen
Wonders of the Solar System Cox concludes by stating that Europa represents the "most fascinating and important alien world we know. A true wonder of the Solar system because it's our best hope of finding extraterrestrial life." An accompanying hardcover book was released on 30 September 2010: The region 1 DVD and Blu-ray discs were released on 7 September 2010. The region 2 DVD and Blu-ray discs of the series were released on 12 April 2010. The region 4 DVD and Blu-ray discs were released on 7 April 2011. Brian Cox from his Twitter account stated that there would be a second series, "Wonders of