Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

July 17, 1997

Message from Earth
Credit: F. Drake (UCSC) et al., Arecibo Observatory (Cornell, NAIC)

Explanation: What are these Earthlings trying to tell us? The above message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of the Arecibo Observatory - still the largest radio telescope in the world - a string of 1's and 0's representing the above diagram was sent. This attempt at extraterrestrial communication was mostly ceremonial - humanity regularly broadcasts radio and television signals out into space accidentally. Even were this message received, M13 is so far away we would have to wait almost 50,000 years to hear an answer. The above message gives a few simple facts about humanity and its knowledge: from left to right are numbers from one to ten, atoms including hydrogen and carbon, some interesting molecules, DNA, a human with description, basics of our Solar System, and basics of the sending telescope. Several searches for extraterrestrial intelligence are currently underway, including Project Pheonix under the direction of Dr. Jill Tarter.

Tomorrow's picture: Blue Stars and Red Pillars

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.