[Solved] White dwarfs have such low luminosity that even the nearest white dwarfs are not visible to the naked eye. Vice President: The second-highest executive officer in a government, who serves as the deputy to the president, and can assume presidential duties under circumstances defined by law, such as the president's death, resignation, or incapacity. Senate Tie: A situation where there is an equal number of votes for and against a measure in the U.S. Senate, often broken by the vote of the Vice President. Twenty-Fifth Amendment: An amendment to the U.S. Constitution that provides procedures for dealing with presidential disability and succession. Presidential Vacancies: Situations where the office of the President becomes temporarily unoccupied due to death, resignation, or removal.