Member-only story
Is empty space really empty?
Space is far from empty. At every moment, a swarm of radiation and particles is passing through you.
Photons of all wavelengths from all directions: visible light, infrared, X-rays, microwaves, neutrino swarms from the sun, and an incessant swarm of virtual particles that arise out of nowhere and annihilate in very short times with their antiparticle. Just that makes space, even in the absence of matter, never empty.
Known matter, made up of quarks and leptons, and the force-mediating bosons, comprise only 4% of everything in the universe.
It is mostly filled with dark energy and dark matter, which do not interact except gravitationally, and thus are very difficult to detect. Whatever they are, they are passing through our bodies right now.
Furthermore, space itself is considered a medium, not a stage. Space and time are a unified fabric in general relativity (and an emergent phenomenon that arises from the evolution of the covariant gravitational field, in the more exotic loop quantum gravity).
