Russia’s new Severodvinsk nuclear-powered attack submarine has successfully completed initial sea trials by builder Sevmash, a Russian shipyard said on Thursday.“The trial was successful. Tests of the ship’s systems were held as scheduled,” Sevmash ship-building company said in a statement.The Russian Navy will receive its first Severodvinsk nuclear submarine in late 2011. Sevmash is planning to build a total of six submarines of this class.Alessandro Morbidelli of the Observatory of Cote d\'Azur argues that the result shows that the distinction between the potential water sources may need to be called into question.\"In the past, scientists thought that these asteroids and comets were completely different classes of bodies. Now, several new results show that primitive asteroids and comets are brothers and sisters,\" he told BBC News.\"This new view changes at least the semantics of the question on the orgin of the Earth\'s water. The question becomes more technical: \'from which region of the disc and by which dynamical mechanism came the (objects) that delivered the water to the Earth?\'\"Herschel has some time left to address the question, but what all the researchers agree is that the Atacama Large Millimeter Array of telescopes in Chile - which has just shown off its first results - will soon be able to resolve these questions with never-before-seen sensitivity.