A NASA rocket experiment that measures infrared light has made a surprise discovery: the universe is far brighter than we thought.
This surplus light, which scientists call a diffuse cosmic glow, exists in the dark space between galaxies and is brighter than all the light produced by all known galaxies in the universe. Instruments on board a suborbital rocket collected the data as part of NASA's Cosmic Infrared Background Experiment, or CIBER. The results were published Thursday in the journal Science.
"These findings redefine what we think of as galaxies," Michael Garcia, a program scientist with NASA, said in an online press conference Thursday. "Instead of having sharp edges, galaxy stars may stretch out in vast distances." This "vast, interconnected sea of stars," NASA says, is a novel understanding of how the universe is constructed.
Scientists have long known that the universe's earliest galaxies emit a red glow and newer, undetected stars produce a blue light. The debate, however, was whether the background light, first discovered by NASA's Spitzer Space Telescope, was coming from those older galaxies or those newer stars.
"The light looks too bright and too blue to be coming from the first generation of galaxies," said James Bock, the principal investigator on CIBER, and a scientist at Caltech and NASA's Jet Propulsion Laboratory. "The simplest explanation, which best explains the measurements, is that many stars have been ripped from their galactic birthplace, and that the stripped stars emit on average about as much light as the galaxies themselves."
CIBER was able to determine this by using infrared cameras launched into space that snap photos for 7 minutes before transmitting the data back to Earth.