We can't compare anything on earth to the biggest things known in space. The Lymann Alpha blob is a bubble like structure containing countless galaxies - perhaps the biggest object in the entire universe.
Regions of radio-emitting gas called "radio lobes" could be even bigger. Then there are super galaxy clusters which are hundreds of galaxies merged together due to cosmic collisions.
Discover which is the largest planet, star, star cluster, constellation, black hole, volcano, galaxy, explosions, moon, storm, impact crater and "void" in space.