Arecibo message
 The Arecibo message as it was transmitted. | |
| Information | |
|---|---|
| Type | Interstellar radio message |
| Purpose | To demonstrate human intelligence and technology |
| Transmitted | November 16, 1974 |
| Location | Arecibo Observatory, Puerto Rico |
| Target | Globular cluster M13 |
| Duration | ~3 minutes |
| Frequency | 2380 MHz |
The Arecibo message is a 1,679-bit interstellar radio message transmitted from the Arecibo Observatory on November 16, 1974. It was designed by a team led by Dr. Frank Drake and Dr. Carl Sagan, among others, and was humanity's first deliberate attempt to communicate with extraterrestrial intelligence.
Content and Encoding[edit]
The message was a simple, binary-coded graphic. It was transmitted at a frequency of 2380 MHz, with a power of 1,000 kilowatts. The message's data is organized as a 73 by 23 raster. The total number of bits, 1679, is a semiprime (73 × 23), which was intended to be a mathematical clue to potential recipients on how to decode the image.
The message contains seven distinct parts, visible when arranged in the 73×23 grid:
1. **The numbers one through ten:** Displayed in binary. 2. **The atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus:** The key chemical elements for life on Earth. 3. **The formulas for the sugars and bases in the nucleotides of DNA.** 4. **The number of nucleotides in human DNA and a graphic of the double helix.** 5. **A figure of a human being:** Showing our physical form and approximate height (relative to the message's wavelength). 6. **A graphic of the solar system:** Indicating which planet (Earth) the message came from. 7. **A graphic of the Arecibo radio telescope:** Showing the transmitter's structure and size.
Purpose and Target[edit]
The message was intended as a demonstration of human technology rather than a serious effort to contact an alien civilization. It was beamed towards the globular star cluster M13, which is about 25,000 light-years from Earth, as it was a convenient and impressive target containing a large number of stars. By the time the message reaches M13, any civilization there would have evolved significantly, making the chances of a reply even more improbable.
Criticism and Controversy[edit]
The Arecibo message has been the subject of ethical debate. Critics, including some scientists like Dr. Stephen Hawking, have argued that sending such messages could be dangerous, potentially alerting hostile extraterrestrial civilizations to our presence. Others question the message's content, noting it is human-centric, difficult to decode without prior knowledge, and may be meaningless to an alien intelligence.
Despite this, the message stands as a historic and symbolic milestone in the search for extraterrestrial intelligence (SETI).
See Also[edit]
References[edit]
- Sagan, C., & Drake, F. D. (1975). "The Search for Extraterrestrial Intelligence". *Scientific American*.
- Staff, A. (1974). "Earth Greets the Stars with a Mathematical 'Hello'". *The New York Times*.
- Heidmann, J. (1995). *Message from Earth*. 1995.