Cosmic strings are theoretical, one-dimensional topological defects that may have formed during phase transitions in the very early universe—similar to cracks forming in ice as water freezes. These strings are incredibly thin (much thinner than a proton) but may be extremely dense, carrying massive amounts of energy per unit length.
They are predicted by some grand unified theories (GUTs) and models of symmetry breaking in high-energy physics. Cosmic strings are not related to string theory, despite the similar name—they are classical field configurations rather than fundamental quantum strings.
Key characteristics of cosmic strings:
- They could stretch across cosmic distances, possibly forming large loops or infinite strands.
- Their immense tension could warp spacetime, producing gravitational lensing or even emitting gravitational waves.
- They might leave observable imprints in the cosmic microwave background or in the distribution of galaxies.
Although no cosmic strings have been detected, they remain an intriguing possibility in theoretical cosmology and might provide insight into the early universe, particle physics, and the nature of spacetime. Detection of a cosmic string would be a groundbreaking confirmation of high-energy physics beyond the Standard Model.