For some reason, the universe is showing far more evidence of ultraviolet light sources than what we actually know exists.
In our day-to-day lives, there are a great many things we expect to go missing eventually. As it turns out, the rule also applies to the outer space, but instead of losing car keys or spare pens the universe is missing light. A lot of it.
“It’s as if you’re in a big, brightly lit room, but you look around and see only a few 40-watt lightbulbs,” said Juna Kollmeier of the Carnegie Institution for Science. “Where is all that light coming from? It’s missing from our census.”
The Cosmic Origins Spectrograph, a $70 million instrument installed on the Hubble Space Telescope, was looking at the hydrogen rivers between galaxies when it noticed something odd: There was far more ionized hydrogen than originally expected. That’s very strange because hydrogen ions are charged when struck by ultraviolet light, and there aren’t enough light sources to account for the excess of 400%. That leaves two possibilities, both with significant implications: either 80% of the light that should be in the universe is unaccounted for, or something else is charging these ions.
“It’s possible the simulations do not reflect reality,” said Benjamin Oppenheimer of University of Colorado Boulder, “which by itself would be a surprise, because intergalactic hydrogen is the component of the universe that we think we understand the best.”
And that’s not even the strangest part. This discrepancy, whatever it may be, is only observable in our local cosmos. In the depths of space, where our universe still seems young, ultraviolet light correctly matches the amount of ionized hydrogen. In other words, whatever is stealing light in our sector of space has begun doing so fairly recently. “The simulations fit the data beautifully in the early universe, and they fit the local data beautifully if we’re allowed to assume that this extra light is really there,” Oppenheimer explained.
Scientists will be reviewing these results, but for now the cause behind our missing light is anyone’s guess. If science-fiction has taught me anything though, it’s either Galactus, the Daleks, or Mr. Burns’ Sunblocker. Feel free to post your own theories in the comments!