Lense-Thiring effect
The Lense-Thiring effect, also known as frame dragging, is an effect in discovered in 1918 by Joseph Lense and Hans Thiring as an outcome of the general theory of relativity. In the Lense-Thiring effect, a compact rotating body, such as a neutron star or black hole, causes the spacetime near it to rotate in the same direction. It may lead to closed time-like paths. Such time machines as the Gödel universe, the Kerr black hole, and the van Stokum cylinder are examples of the Lense-Thiring effect in action, as, in some sense, is the Gott loop, since a couple of cosmic strings passing each other would have an enormous angular momentum as a system.