Scientists at a US conference have said it is time to try actively to contact intelligent life on other worlds.
Researchers involved in the search for extra-terrestrial life are considering what the message from Earth should be.
The call was made by the Search for Extra Terrestrial Intelligence institute at a meeting of the American Association for the Advancement of Science in San Jose.
But others argued that making our presence known might be dangerous.Researchers at the Seti institute have been listening for signals from outer space for more than 30 years using radio telescope facilities in the US. So far there has been no sign of ET.