Dark side of the moon holds clues to early universe
CU Boulder researchers are working to put a satellite in orbit around the moon to observe the universe’s “dark ages”—an era just 15 million years after the Big Bang, before the cosmos’ first stars had begun to flare into existence.
NASA recently picked the Dark Ages Polarimetry Pathfinder (DAPPER) as one of nine small satellite missions that it will study for a potential launch in the next decade. The DAPPER team, which is led by CU Boulder astrophysicist Jack Burns, will spend the next six months crafting a detailed design of this proposed mission. The goal would be to detect the faint signals from the clouds of hydrogen gas that once filled the early cosmos.
“By using a combination of this hydrogen signal and the very quiet environment of the lunar far side, we can probe the dark ages of the universe for the first time,” said Burns, a professor in the Department of Astrophysical and Planetary Sciences.
The proposal comes as nations and companies around the world are setting their sights on traveling to the moon. Burns’ team has proposed launching their small satellite, which would be cheaper to build and more compact than a full-scale NASA mission, from the Lunar Gateway—a space station that NASA and other international partners plan to orbit about the moon over the next decade.
The moon is the only place near Earth where scientists could carry out a scientific study like DAPPER, Burns said. Signals from the early universe can be blocked by Earth’s atmosphere or drowned out by other radio waves, such as FM radio broadcasts. The far side of the moon, in contrast, is one of the most radio silent places in the inner solar system, Burns said.
The universe’s primordial hydrogen gas likely emitted electromagnetic radiation that astrophysicists could see today in radio waves. In early 2018, another research team reported that it may have detected a similar signal from later on in the cosmos’ evolution, roughly 180 million years after the Big Bang.
“One of the nice things about going into space is that we’re able to eliminate most of that inference,” he said.
The potential for such a mission is huge, Burns added. By exploring this early period in the universe’s history, scientists could gain new insights into how the cosmos evolved. How, for example, did those primordial clouds of hydrogen gas eventually collapse to form all of the stars and galaxies that exist in the universe today?
Probing the dark ages could also provide astrophysicists with new hints about the nature of dark matter. This elusive substance makes up 85 percent of the mass of the galaxy but has yet to be seen by scientists.
Other leaders on the DAPPER team include scientists at the University of California, Berkeley, National Radio Astronomy Observatory in Charlottesville, Virginia, and NASA Ames Research Center in Mountain View, California.