Physicists have struggled for seven decades with the question of why there is more matter in the universe than antimatter.

They found that normal matter (made of familiar particles like protons and neutrons, collectively called baryons) makes up about 4 to 5 percent of the cosmos’ total energy density. (The ...

With the Cosmic Origins Spectrograph on Hubble, we are conducting UV spectroscopic studies of missing baryons in the intergalactic medium, quasar ionizing spectra, mass estimates of super-massive ...