Archaeologica.org

1. The flyby problem

When scientists send their spacecraft across the universe, they save fuel by performing “slingshot fly-bys”. This is where, rather than firing up the thrusters, the craft changes its trajectory by harnessing the enormous gravitational pull of a planet. However, this trick has had an unexpected side-effect: it seems to produce a change in speed that no one can account for. In 1998, for example, NASA's NEAR Shoemaker spacecraft had its speed boosted by an additional 13.5 millimetres per second. There are many examples of this, but no explanation – which raises the tantalising possibility that it could be a sign that a whole new branch of physics is waiting to be discovered.

The history of the universe may require a re-write.