These are the cosmic voids.The smallest voids are about 20 million light-years across on a side, and the largest ones go for hundreds of millions of light-years.

Cosmic rays—high-energy particles moving close to the speed of light—originated from somewhere in the Milky Way galaxy and beyond, but exactly where has been a mystery since they were ...

An ultra-high-energy cosmic ray carries tens of millions of times more energy than any human-made particle accelerator such as the Large Hadron Collider, the most powerful accelerator ever built ...

Using data from the Keck Cosmic Web Imager, an animation has been created that "reveals a 3-D slice through a network of hydrogen gas filaments that crisscross the spaces between galaxies ...

The puzzling cosmic ray had an estimated energy of 240 exa-electronvolts (EeV; 10 18 electronvolts), making it comparable to the most powerful cosmic ray ever detected, aptly named the Oh-My-God ...