Moons of Jupiter
* Apollo 11 was the first manned spacecraft to land on the moon.
* The approximate periodicity is 11 years in sunspot cycle.
* Messier object M11, a magnitude 7.0 open cluster in the constellation Scutum, also known as the Wild Duck Cluster.
* The New General Catalogue object NGC 11, a spiral galaxy in the constellation Andromeda
* The Saros number of the solar eclipse series which began on -2511 December 26 and ended on -1158 March 18. The duration of Saros series 11 was 1352.2 years, and it contained 76 solar eclipses.
* The Saros number of the lunar eclipse series which began on -2389 June 19 and ended on -1037 September 8. The duration of Saros series 11 was 1352.2 years, and it contained 76 lunar eclipses.
* The 11th moon of Jupiter is Himalia.
# he interval of an octave and a fourth is an eleventh. A complete eleventh chord has almost every note of a scale.
# The number of thumb keys on a bassoon, not counting the whisper key. (A few bassoons have a twelfth thumb key).
There are eleven players on a soccer team on the field at a time as well as in a cricket team. Within a school or college, the phrases "the football XI" and "the cricket XI" generally refer to the first (best) team currently playing. Other teams are often referred to as "the second XI" etc.
In cricket, 11 is the number of players from the fielding (or bowling) side on the field of play at any one time.
An American football team also has eleven players on the field at one time during play.
The car number of Darrell Waltrip and Cale Yarborough when they won their NASCAR Winston Cup Series championships. Denny Hamlin now drives a car with this number.
In rugby union the left wing wears the 11 shirt.
* The number of guns in a gun salute to U.S. Army, Air Force and Marine Corps Brigadier Generals, and to Navy and Coast Guard Rear Admirals Lower Half.
* The Military Occupational Specialty (MOS) designator given to US Army Infantry (AKA 11 Series, or 11B, 11C, 11D, 11H, 11M, etc)
* The number of General Orders for Sentries in the Marine Corps.
* A page in the Service Record Book of an enlisted Marine for writing down disciplinary actions.
* World War I ended with an Armistice on November 11, 1918, which went into effect at 11:00 am-the 11th hour on the 11th day of the 11th month of the year. Armistice Day is still observed on November 11 of each year, although it is now called Veteran's Day in the United States and Remembrance Day in the Commonwealth of Nations and parts of Europe.
The number 11 bus is one of the best and cheapest ways of sightseeing in London