Could invisible strings hold the universe together?

The answer

Cosmic strings are hypothetical one-dimensional topological defects in spacetime that may have formed during phase transitions in the early universe, similar to cracks that form in ice. If they exist, they would be incredibly thin (smaller than a proton's width) yet extraordinarily dense - a single kilometer could weigh as much as the Earth. They would warp spacetime around them, creating distinctive gravitational lensing effects. While no cosmic strings have been confirmed, their detection would provide profound insights into conditions in the first fractions of a second after the Big Bang.