A hypothetical one-dimensional, string-like object that is made from a curvature of space.
a long, stretched out, very massive object, with a gravitational field which is not spherically symmetric around a point (like a black hole), but cylindrically symmetric around a line
a similar type of highly concentrated matter, except in most cases it can only interact via gravity
a two-dimensional version of a black hole
A long, heavy object from Quantum Field Theory or String Theory, which is very thin. They may have been created in the early life of the Universe, and would now stretch across the entire Universe. No cosmic string has ever been observed. They may or may not exist.
Cosmic strings are thin strands of ultrahigh density matter that are predicted by some theories to have been left over from an extremely early era of the universe. Cosmic strings would have a width that is far less than an atomic nucleus, and a mass of about 10 million billion tons per centimeter. A kilometer of cosmic string material would weight as much as the Earth! They would make closed loops or stretch across the universe and perhaps have an infinite length. Cosmic strings are not to be confused with superstrings, the tiny subatomic loops of matter that according to superstring theory are the fundamental building blocks of all particles.
A tubelike configuration of energy that is believed to have existed in the early universe. A cosmic string would have a thickness smaller than a trillionth of an inch but its length would extend from one end of the visible universe to the other.
A cosmic string is a hypothetical 1-dimensional topological defect in the fabric of spacetime. Cosmic strings are hypothesized to form when different regions of spacetime undergo phase changes, resulting in domain boundaries between the two regions when they meet. This is somewhat analogous to the boundaries that form between crystal grains in solidifying liquids, or the cracks that form when water freezes into ice.