Alien SETI signal. Computer artwork of a possible method that an advanced alien civilisation could use to signal its presence to other lifeforms in the universe. The method involves building large structures (red) that would orbit a star and eclipse that star periodically. This would appear as a blinking star to someone looking from the right direction. This idea was proposed by Luc Arnold of the Observatory of Haute-Provence in France. Future telescopes will be capable of detecting such signals, which are thought to be as effective as the laser and radio signals being searched for by SETI (Search for Extra-terrestrial Intelligence).