Travelling at the speed of light, it will take 20 years for the messages to reach their target destination Gliese 581d, the nearest Earth-like planet outside our solar system.
The interstellar communication project, dubbed Hello From Earth, was part of National Science Week, and invited Australians to log on to a website and write a personal message to the stars.
It has attracted attention from around the world, from Afghanistan to Antarctica.
Hello from Earth spokesman and the editor of the Australian science magazine, COSMOS, Wilson da Silva, said more than 1000 newspapers and 9000 blogs had reported on the project.
He said the exciting thing about the project was inspiring people to think about where humans came from and whether intelligent life existed outside Earth.
