On this day in space! Nov. 16, 1974: Arecibo Observatory broadcasts interstellar message

News
By , last updated

On Nov. 16, 1974, humans sent their first message to the stars in an attempt to contact extraterrestrials.

On Nov. 16, 1974, humans sent their first message to the stars in an attempt to contact extraterrestrials. They did this using what was then the largest radio telescope in the world, located at the Arecibo Observatory in Puerto Rico.

Arecibo Observatory overlayed with the message for extraterrestrials it transmitted in 1974. (Image credit: National Astronomy and Ionosphere Center (NAIC))

Because M13 is 25,000 light-years away, it will take 25,000 years for any M13 aliens to hear our message — if they are even out there. The Arecibo message is only one of several messages intended for extraterrestrials. We have also included messages on several spacecraft, such as Pioneer and Voyager.

On This Day in Space: See our full 365-day video archive!

Hanneke Weitering
Hanneke Weitering
Contributing expert

Hanneke Weitering is a multimedia journalist in the Pacific Northwest reporting on the future of aviation at FutureFlight.aero and Aviation International News and was previously the Editor for Spaceflight and Astronomy news here at Space.com. As an editor with over 10 years of experience in science journalism she has previously written for Scholastic Classroom Magazines, MedPage Today and The Joint Institute for Computational Sciences at Oak Ridge National Laboratory. After studying physics at the University of Tennessee in her hometown of Knoxville, she earned her graduate degree in Science, Health and Environmental Reporting (SHERP) from New York University. Hanneke joined the Space.com team in 2016 as a staff writer and producer, covering topics including spaceflight and astronomy. She currently lives in Seattle, home of the Space Needle, with her cat and two snakes. In her spare time, Hanneke enjoys exploring the Rocky Mountains, basking in nature and looking for dark skies to gaze at the cosmos. 

You must confirm your public display name before commenting

Please logout and then login again, you will then be prompted to enter your display name.