Dark Matter

Dark matter was more mysterious than it was originally thought. Apart from being WIMP – Weak Interacting Massive Particles, it was also unstuck in space-time. Once properly exited, it could open up corridors to other times. Since the dark matter interacted with the gravitational forces of the rest of the universe, they stayed linked to the same relative location of space, despite the movement of things that otherwise occurred across time.

The only downside was that it required a certain amount of intelligence to navigate. One couldn't simply send through objects – even the best drones were having a tough time making a successful trip – let alone ending up when and where they should.