Experts are looking up at the stars and thinking "it shouldn't be so dark up there." New readings from the Hubble Space Telescope have shown that there is a whopping 80 percent deficit in known ultraviolet light in the Universe compared to what models imply.

Pure ultraviolet (UV) rays are mostly invisible to the naked eye as they have wavelengths that are shorter than visible light. Some wavelengths can be seen at incredibly high frequencies that make them appear violet in color - as seen with UV lamps. Electric arcs also can also produce incredibly bright moments of UV light.

According to researchers from the University of Colorado (CU) Boulder's Center for Astrophysics and Space Astronomy, this light can travel incredibly far distances across the known Universe, charging initially neutral hydrogen atoms along the way.

Interestingly, using the CU-designed Cosmic Origins Spectrograph on the Hubble telescope, the researchers found far more charged ions than can be explained with all the known UV light in the Universe - which mostly comes from quasars.

Strangest of all, in young galaxies billions of light years away, everything adds up. However, the closest and most well-studied portions of the Universe appear to be the ones missing the most UV light.

"If we count up the known sources of ultraviolet ionizing photons, we come up five times too short," researcher Benjamin Oppenheimer said in a statement. "We are missing 80 percent of the ionizing photons, and the question is where are they coming from? The most fascinating possibility is that an exotic new source, not quasars or galaxies, is responsible for the missing photons."

The researchers suggest that the decay of invisible dark matter might be responsible for leaking this inexplicable "missing" light.

David Weinberg, who co-authored a study on this discovery with Oppenheimer, claims that this is actually good news because it comes with certainty that there is actually something really wrong with current models of the Universe.

"We still don't know for sure what it is, but at least one thing we thought we knew about the present day Universe isn't true."

The study was published in Astrophysical Journal Letters.