Scientists recreated the universe's first 2 billion years

Physicists have built a computer simulation that recreates the universe's first 2 billion years, from the darkness after the Big Bang through the slow arrival of light. The project, called Lumina, comes from a study out of the Harvard and Smithsonian Center for Astrophysics, and it draws on data from the James Webb and Nancy Grace Roman space telescopes. It captures two long-theorized events in detail for the first time: the re-ionization of hydrogen, and later of helium, the moments light could finally travel freely. The simulated volume is 100 times larger than previous efforts. "To understand what we are seeing with this telescope, we need to translate our theories into detailed predictions," said lead author Oliver Zier, who described years of ups and downs before the results arrived. The team is now giving Lumina to other scientists to check against real telescope snapshots. The early universe, it turns out, left notes.