Are aliens hiding in plain sight?

‘You can’t hunt for something if you have no idea what it is’: An artist’s impression of Mars. Photograph: Alamy Stock Photo

Several missions this year are seeking out life on the red planet. But would we recognize extraterrestrials if we found them?

Mars covered in toxic chemicals that can wipe out living organisms, tests reveal

Mars is bathed in ultra violet light which turns the Martian soil sterile. Photograph: Reuters

Discovery has major implications for hunt for alien life on the red planet as it means any evidence is likely to be buried deep underground

The moon, Mars and beyond… the space race in 2020

Not since the 1960s have we witnessed such appetite for space missions. Here’s what to expect in the year ahead, from commercial launches to Chinese ambitions