Sputnik Anniversary Today Launches World Space Week

The Space Age officially began 53 years ago today, when the Soviet Union launched Sputnik, the world's first man-made satellite. While the original event set off fear and Cold War rivalries, today it is honored with the kickoff of an international space celebration.

This week, organizations across the globe celebrate the 11th annual World Space Week, which highlights the contributions of space science and technology to life on Earth.

World Space Week is held every year from Oct. 4-10, with coordinated events taking place around the world. It's the largest annual public space event in the world, according to the event's planners. [Timeline: 50 Years of Spaceflight.]

This year's theme is "Mysteries of the Cosmos," and activities include a Google Lunar X Prize Summit on the Isle of Man, an astronomy festival in Marrakech, Morocco, and a star camp for high school students in Jeddah, Saudi Arabia.

"World Space Week is the time each year when the public can learn about the many benefits of space exploration, and students are inspired through space to excel in school," Dennis Stone, president of the World Space Week Association, said in a statement. "World Space Week is open to everyone."

The United Nations established World Space Week in 1999, and the event was first held a year later. The U.N. continues to help coordinate the annual celebration, according to the World Space Week Association.

World Space Week's start and end dates are the same every year. They mark two key events in the history of space exploration: the Oct. 4, 1957 launch of Sputnik,  and the date  the Outer Space Treaty went into effect on Oct. 10, 1967. The Treaty formed the basis for international space law.

World Space Week also follows closely on the heels of NASA's 52nd anniversary ? the space agency became operational on Oct. 1, 1958.

Last year, when World Space Week's theme was "Space for Education," 713 events were held in 55 nations, according to officials. President Obama joined in, throwing a star party for middle-school students on the White House lawn.

Other activities scheduled for this year:

• Public astronomy lectures in Helsinki, Finland.
• The inauguration of a mobile planetarium and telescope in Thrissur, India.
• Rocktober skies, a regional rocket launch in Alabama.

This is a busy week for astronomy events, and not all of them are formally connected to World Space Week. The American Astronomical Society's Division for Planetary Sciences, for example, is holding its annual meeting Oct. 3-8 in Pasadena, Calif.

• Video: 50 Years of Spaceflight
• Timeline: 50 Years of Spaceflight
• Welcome to Astronomy: Getting Started