claim: The Tenth Doctor travels alone in The End of Time.
evidence: A Lowitz arc is an optical phenomenon that occurs in the atmosphere ; specifically , it is a rare type of ice crystal halo that forms a luminous arc which extends inwards from a sun dog -LRB- parhelion -RRB- and may continue above or below the sun .. optical phenomenon. atmospheric optics. ice crystal halo. halo ( optical phenomenon ). sun dog. sun dog