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IF YOU want to send a message to aliens, it’s wise to check that it makes
sense—as two Canadian mathematicians have found out.

Yvan Dutil and Stephane Dumas of the Defense Research Establishment
Valcartier near Québec City designed a 300 000-bit coded message for
broadcast to extraterrestrial civilisations by Encounter 2001, a company in Houston
(This Week, 9 January, p 15).

But in a section of the message where Dutil and Dumas were describing the
radius and circumference of a circle, they slipped up and used the wrong symbol
for an equals sign.

The error—a missing vertical bar in the symbol—would probably
have left aliens scratching their heads in confusion. And Dutil admits that it
certainly wouldn’t have done much for our intellectual standing among our
galactic neighbours.

The error was spotted by Dutch computer programmer Paul Houx, who read
extracts from the message in a popular science magazine. Dutil and Dumas then
spent several tense days trying to contact the team who were to broadcast the
message from a radio telescope in Ukraine. They made the correction just in the
nick of time before its broadcast on 24 May.

But now Dutil is fretting over other typos that might be lurking in the
text—a feeling New ������ý’s subeditors know all too
well. “There is still a possibility that something will slip through,” he says.