You could swim through the deepest voids and encounter a single hydrogen atom in an entire football field's worth of space. When you purchase through links on our site, we may earn an affiliate ...

"Dark matter can be red hot when it is born, but still have time to cool down before galaxies begin to form." When you purchase through links on our site, we may earn an affiliate commission. Here’s ...

Cosmic strings are artifacts of what the universe looked like in the moments before it rapidly changed from a high-energy to low-energy environment—the Big Bang. Today, scientists believe cosmic ...