On this day in history - June 30

What Happened On This Day – June 30

• 1972 The first leap second is added to UTC

  Leap seconds are added to Coordinated Universal Time (UTC) from time to time to account for the Earth's slowing rotation. UTC is the basis for the calculation of local times worldwide.

• 1971 The crew of Soviet spacecraft “Soyuz 11” dies after the loss of air supply

  The cause of the tragedy was a faulty valve. The three cosmonauts had previously achieved the first docking of a spacecraft to a space station in history.

• 1936 The novel “Gone with the Wind” is published

  Margaret Mitchell's story set in the American South during the American Civil War became one of the United States' biggest best-sellers. The 1939 movie version starring Vivien Leigh and Clark Gable was similarly successful.

• 1908 The Tunguska event leaves 2000 square km of Siberian forest flattened and scorched

  The devastation is believed to have been caused by the explosion of an asteroid or comet. It is the largest impact event in recorded history.

• 1905 Albert Einstein submits a paper outlining his theory of special relativity

  The text “Zur Elektrodynamik bewegter Körper” comprises the currently accepted theory about the relationship between space and time. The theory of special relativity is the basis for his theory of general relativity, which he published in 1916.