• Feedback said that Darren Wright, of the project to beam biscuit adverts to aliens, is an astronomer (5 July). He is a lecturer in radio and space plasma physics who lists his research interests as "Things".
• We said that Australian companies "forecast spending $800 between 2002 and 2013 on geothermal exploration" (19 July, p 24). That should have been $800 million.
• The food business may well be "bad for the plant and your health", but the subtitle of the book Eat Your Heart Out, by Felicity Lawrence (reviewed 5 July, p 47) refers to the planet.
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