system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who-Series 6] Why did The Silence stick around Earth for 2,000 years just to get humanity to build a space suit when they have time ships that can travel in space? and are from the 51st century anyway?

Seems a bit redundant to me.
gpt
The space suit is not for space travel. They were attempting to kill the doctor and so created a fixed point in time where the doctor must die to an impossible astronaut on the shore of lake silencio in Utah. To the silence, the event had already happened and so they went back in time to cause the event that would cause them to go back in the first place. It is one of the weird events where an event happens in the present which causes something in the future to go back in time to guarantee it happens. Like how the doctor warns himself about his own death in the first episode by inviting himself to his own death, causing him to create the invitations.