But the editor who placed this tag here didn't say why.
Talk about it here.
The Time Crack is a mysterious crack in the fabric of time and space caused by an unidentified explosion, and is the focus of the main story arc for Series 5. The Crack releases energy of "pure time" that can wipe individuals out of time itself and remove events from history, though time-travelers such as the Doctor still have the ability to remember them. The Crack can also close itself and subsequently travel to another time. The closed Crack can be opened by a Sonic Screwdriver. The Crack seemingly erased events such as the CyberKing (DW: The Next Doctor) and the Dalek invasion of 2009 (DW: The Stolen Earth/Journey's End).
One in Amy Pond's bedroom connected it to an Atraxi prison in 1996. (DW: The Eleventh Hour) Later appearances of the Crack were on the Starship UK in the 33rd century (DW: The Beast Below) and the Cabinet War Room in 1941. (DW: Victory of the Daleks) The Crack later opened to an incredibly large size aboard the Byzantium in the 51st century. It erased Christian, Marco, Pedro, Phillip and the Weeping Angels from existence and subsequently closed. The Weeping Angels themselves had feared it, and attempted to escape. (DW: Flesh and Stone)
For an unknown reason, unbeknown to Amy until her encounter with the Weeping Angels, the Crack has been following her everywhere she went with the Eleventh Doctor, appearing wherever she went after she arrived.
The Doctor stated that the only other way to close the Crack is for it to consume a complicated space-time event: him or the Weeping Angels (due to all of them being equal to himself). River Song volunteered to let herself be consumed but, the Doctor laughed at her idea and said she isn't even as complicated as one Angel. The Doctor instead sealed the crack by launching the Angels into it. At the end of the episode, he traced the origin of the temporal explosion behind the crack to the day of Amy's wedding.
It appears the crack will continue to follow the Doctor and Amy wherever they go. Where the cracks came from is unknown, though Prisoner Zero seemed to show an advanced knowledge of them.
Time Crack Gallery
The first Crack, seen on Amy Pond's bedroom wall. (DW: The Eleventh Hour)
- Secondcrack.png
A Crack shape seen on TARDIS's television. (DW: The Eleventh Hour)
- Crack 3.png
The third Crack, seen on the side of Starship UK. (DW: The Beast Below)
- Fourth crack.png
The fourth Crack seen in the wall behind the TARDIS as it dematerialises. (DW: Victory of the Daleks).
- Crack5byzantium.png
The fifth Crack seen inside the Byzantium. (DW: Flesh and Stone).
Behind the Scenes
- The Time Crack was inspired by a crack Steven Moffatt saw in his son's bedroom.
- Moffat has confirmed that the Crack will appear in most episodes.
- The Cracks arc is, like the previous series (excluding the Bad Wolf meme), foreshadowed in a previous series, in this case in "The Next Doctor" (though, perhaps unintentionally).