Inhabitants of the planet Gliese 581d will need a radio receiver and the ability to interpret binary code if they were to understand a series of text messages to be sent from Australia.
But the good news was they have another twenty years "give or take a few months" to get hold of both.
Hello from Earth will collect text messages over the next 12 days and transmit them to the closest Earth-like planet that has the potential to harbour life.
"All the messages will be collected 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," the website said.
"This system of on and off radio signals will be sent back to Australia to the NASA/CSIRO Canberra Deep Space Communication Complex at Tidbinbilla, near Canberra. [Also] known as Deep Space Station 43, [it] will transmit the signal to Gliese 581d on 24 August 2009."
Gliese 581d is said to be a "super-Earth about eight times heavier" than Earth.
"It and three known sister planets orbit the low-mass red dwarf star Gliese 581, about 194 trillion kilometres away from us, in the constellation Libra," the site said.
It was chosen because it represented the best chance to receive a response in the message senders' lifetime.
But the site warned that any response received would need to be forwarded through the correct channels, including the Search for Extraterrestrial Intelligence (SETI), for international consultation to develop a response.
Coordinates of the responding planet could also not be disclosed, the website said.
At the time of writing, the site had received 87 messages including invitations to visit New Zealand and Wyoming on the NSW central coast, and requests not "to eat our brains" and to "please bring a carton of milk if you come to visit."
One respondent apologised for the messages which he dubbed "an example of our primitive humour."
No spam appeared to have been submitted - yet.
The site, a showpiece of National Science Week, appeared to experience a brief outage of approximately 45 minutes shortly after its launch, but has since been brought online again.