Intergalactic gas filaments crisscross the universe
They crisscross the cosmos like cobwebs in a room that hasn't seen a vacuum cleaner in a long time: In so-called filaments, unfathomably large, threadlike structures of hot gas that surround and connect galaxies and clusters of galaxies, astrophysicists have long suspected the previously hidden half of matter in our universe. We owe our existence to a tiny error. After the big bang 13.8 billion years ago, the matter of the cosmos spread out in a gigantic gas cloud and was almost evenly distributed in it. Almost, but not quite: in some parts the cloud was somewhat denser than in…