A network of UK researchers has decided to compose a message to aliens - but they are divided over whether such a message should be sent into space.
The group will enter the Breakthrough Message contest, which offers a $1m prize for creating a digital missive that represents human civilisation.
That prize accompanies a new effort to accelerate the search for extra-terrestrial intelligence (Seti).
Experts have argued for decades about the wisdom of broadcasting into space.
Listening out for aliens is one thing, but trying to contact them raises myriad concerns about what happens when civilisations collide.
The diversity of views was obvious at a conference of the UK Seti Research Network (UKSRN) in Leeds, where the group's 20 members were split down the middle in an informal vote.Some letters are better left unsent. To read more, click here.