The way the Earth changes its tilt. See 'A Brief History of Climate Change'.
Obliquity
Fact of the Day
Before the Normans came along, there was no English word for 'castle'.
Quote of the Day
"Grant that we may from henceforth show ourselves neither bastards nor dastards.
"
~ Peter Wentworth on the House of Commons' freedom of speech, 1576
On This Day
1554 Thomas Wyatt the Younger was executed for leading the Wyatt Rebellion against Mary I's marriage to Philip of Spain.
1689 William III and Mary II were crowned as joint sovereigns of England.
1814 The Treaty of Fontainebleau was signed. It forced Napoleon to abdicate and exiled him to the island of Elba.
1890 Joseph Merrick, more commonly known as the Elephant Man, died aged 27. No-one knows what caused his condition, but it's thought that he died of asphyxiation or a dislocated neck when he attempted to sleep lying down.
1945 American soldiers liberated Buchenwald Nazi concentration camp.
1961 Adolf Eichmann's trial started in Israel. He was charged with 15 crimes, including crimes against humanity and war crimes.
1970 Apollo 13 launched on its mission to the moon, but an explosion caused the mission to be abandoned.