Deep Space Station 43 Canberra, Australia NASA

NASA and COSMOS magazine will give us a chance to send a 160-character text message to our alien brothers and sisters on Gliese 851d on August 24 2009 in celebration of the International Year of Astronomy 2009.

COSMOS magazine thought it would be a nice way to celebrate National Science Week in Australia and the International Year of Astronomy 2009 by sending a message to a potentially habitable planet outside the Solar System.

With the support of Australia’s Department of Innovation, Industry, Science and Research, the CSIRO and NASA, and a the text messages collected on their website, “Hello from Earth” will be transmitted to the closest Earth-like planet that might harbor life: Gliese 581d (pronounced ‘glee-suh’).

Gliese 581d, just over twenty light years from us, is eight-times the size of Earth and is classified as a “super Earth” and is one the first water world candidates according to one of its discoverers Stephane Udry from the Geneva Observatory in Switzerland. Gleise 851d resides in the habitable zone of its star. Planets in this zone are just the right distance for liquid water to potentially exist.

“On Sunday the 23rd of August 2009, all the messages will be collected from the Hello from Earth website and exported as a text file and sent to NASA’s Jet Propulsion Laboratory in California, where it will be encoded into binary code, packaged and tested before transmission. These radio signals will be sent back to Australia to the NASA/CSIRO Canberra Deep Space Communication Complex at Tidbinbilla, near Canberra.”

The signal will reach the solar system of Gliese 581 (the parent star) around December 2029 give or take a few months. The radio signal will cross 20.3 light-years 192 trillion km of interstellar space before reaching the planet. If there is a response, it will probably need to travel the same way back  “unless Gliesans have improved communication technologies, the soonest we could hope to receive an answer would be in 42 years around 2051,” says COSMOS.

You can read quite a few of the messages on the website and in the FAQs, COSMOS mentions that SETI (the Search for Extraterrestrial Intelligence) Institute’s program in interstellar message composition is part of its mission to “explore, understand and explain the origin, nature and prevalence of life in the universe.”

What happens if “the aliens” respond:

From the SETI Post-Detection Taskgroup of the International Academy of Astronautics, chaired by Paul Davies: “If anyone or anything calls back, the protocol asks for the discoverer to inform all relevant scientific bodies, such as the taskgroup, as well as the government of the country concerned, says Davies.”

Other messages sent into space in the past are:

• Simple plaques on NASA’s Pioneer probes (10 and 11, launched in 1972 and 73)
• The golden records on the Voyager probes (1 and 2, launched in 1977)
• The beaming of the Beatles song “Across the Universe”, sent by NASA last year from Madrid towards the star Polaris
• The Cosmic Call project, which in 1999 beamed a three-hour long message to four Sun-like stars within 70 light-years.
• Submissions until 5:00 p.m. Monday, 24 August 2009 Sydney time 3:00:00 a.m. Monday, August 24, 2009 US/Eastern

COSMOS magazine Hello from Earth Project