Astronomy
Topological Defects and the Birth of Cosmic Structure
Quick fact
In the first fraction of a second after the Big Bang, the universe is thought to have undergone a phase transition that could have created 'cosmic strings'—ultra-dense, thread-like remnants of the original high-energy state. These strings, some as long as the observable universe, may have acted as gravitational seeds around which galaxies and clusters eventually formed.
Why this is interesting
You've seen how a freezer changes liquid water into solid ice, but did you know the entire universe may have experienced a similar cooling that left permanent 'cracks' in the fabric of space itself?