An Einstein-Rosen bridge, colloquially known as a wormhole is an absolute distortion of space-time which allows near instantaneous transit to anywhere in the universe. Commonly, they fold space through a higher dimensions as topological fixtures in spacetime not unlike mountains or rivers in terrain. Visually, a wormhole is a three dimensional “look” at the exit point, meaning observations can be made about the destination before travelling through one and starcharts can be formed before travelling if a new wormhole is discovered.
It is not known if they are natural or artificial - and as such, many conspiracy theorists postulate that their existence is “too convenient”. They are typically mass-locked to positions near objects of large mass or size such as stars or gas-giants though they have been found in rare cases on exotic planetoids.
The first wormhole was discovered via the LAUYGA recievers observing a neutron star colliding with a black hole - shining through the wormhole.