Missing cosmic sources elude astrophysicists

The universe is bright but are they in the Dark?

Using computer simulations, researchers at the Carnegie Institution for Science have determined that in the intergalactic medium (IGM)—the space between galaxies—there is actually more light being emitted than there should be by a factor of 400%.1

The light observed coming from the ionized hydrogen atoms in the IGM is five times more than there should be.

Simulations of the early big bang universe agree with the amount of light generated by sources observed at those epochs, but they widely disagree with the universe we observe much closer to home, in the low-redshift universe, meaning much more recent in its alleged history.

Quasar light missing

Figure: An artist’s impression of a quasar. There’s just not enough of them to account for interstellar light, say researchers. Credit: NASA/ESA See Ref. 1.

Cosmologists have this problem because they assume that along with active star-forming galaxies, quasars—extremely active galaxy-sized objects, which emit a lot of radiation and often have large redshifts—are the main sources to have photo-ionized the IGM. This is because they assume that having large redshifts means that they are predominantly the occupants of the early universe, from which all normal galaxies that we see at low redshifts ultimately are supposed to have evolved. It is this initial big bang model assumption which brings them unstuck. Continue reading