New instrument begins to measure total light ever emitted in the universe

A new instrument made a short jaunt into space this weekend, as part of a mission to measure total light never emitted in the history of the universe. The CIBER-2 project will search for stray stars hiding between galaxies by monitoring the cosmic background glow of infrared light.

The cosmic infrared background experiment-2 (CIBER-2) is designed, as the name suggests, to measure the cosmic infrared background. This uneven pattern of radiation permeates the universe, highlighting where galaxies cluster together, and its analysis can teach astronomers a lot about the distribution of stars and other objects in space.

On Sunday June 6, CIBER-2 made the first of five space trips to study this phenomenon. The instrument was launched on a NASA Black Brant IX sounding rocket from New Mexico, reaching an altitude of about 300 km (186 miles) for 10 minutes, before being returned to Earth.

During its time aloft, CIBER-2 sweeps over a patch of sky equivalent to about eight times the full moon. It takes measurements of the cosmic infrared background at six wavelengths, allowing scientists to later analyze the data to learn more about the stars or other objects that produced it.

This could help answer some important questions. The vast majority of stars are believed to reside in galaxies, but data from the Spitzer Space Telescope revealed there was more light in the cosmic infrared background than expected, based on known galaxy populations.

Two explanations for this have been put forward by different teams. One of them suggested that the extra light was coming from the very first stars and black holes that ever formed. The original CIBER mission, meanwhile, found evidence that there may be more stars roaming free outside galaxies than we thought.

CIBER-2 could help solve the problem by scanning the sky in more wavelengths than Spitzer or the original CIBER, allowing it to analyze spectra of light from different sources. For example, the very first stars and black holes would be enveloped in a fog of hydrogen, which permeated the early universe, and which would affect the spectrum of colors in their light. But stars that have formed more recently do not pass through this hydrogen, so their light is different.

“This background glow is the total light produced over the course of cosmic history,” says Jamie Bock, senior scientist at CIBER missions. “Our method measures the total light emitted over the course of cosmic history, including any sources that astronomers may have missed.”

After last weekend’s successful flight, CIBER-2 will be launched four more times over the next five years for further analysis. The data collected during the mission will help inform the design of a future telescope, called a Spectrophotometer for the History of the Universe, the Era of Reionization and the Ice Explorer (SPHEREx). Due to launch in 2024, SPHEREx will scan the sky at an astonishing 102 wavelengths over two years, for a truly deep look at the cosmic infrared background.

Source: Caltech