Little is known about what was happening shortly after the big bang, but now researchers are hoping to shed fresh light on the matter by harnessing the dark side of the moon.<\/p>\n
Scientists are hoping to put a suitcase-sized satellite into orbit around the moon, using the data it collects as it passes the far side to search for a radio frequency signal emitted by neutral hydrogen atoms in the early universe.<\/p>\n
More specifically, the satellite, nicknamed CosmoCube, will be looking for what is known as the 21cm line. Crucially, the older the signal, the more its wavelength has been stretched, or redshifted, to longer wavelengths, providing a way for its strength to be tracked over time relative to the cosmic microwave background radiation.<\/p>\n
\u201cThe main thing we track by looking at this signal is what\u2019s the physical temperature of the gas during the early universe,\u201d said Prof Eloy de Lera Acedo, the lead author from the University of Cambridge\u2019s Cavendish Laboratory.<\/p>\n
With the 21cm signal acting a bit like a thermometer, the team are hoping to study events from the start of the so-called \u201cdark ages\u201d, about 380,000 years after the big bang, through the cosmic dawn, when the first stars and galaxies emerged, to the end of what is known as the epoch of reionization, approximately 1bn years after the big bang.<\/p>\n
\u201cThe temperature of the gas is affected by the things happening in the universe at the time,\u201d said de Lera Acedo. In addition he noted the amplitude and shape of the 21cm signal was expected to be influenced by dark matter, offering a way for experts to investigate the nature of this mysterious component of the universe.<\/p>\n
A representative model of the CosmoCube undergoing tests. The 21cm line is the radio frequency signal emitted by neutral hydrogen atoms in the early universe. Photograph: RAL Digital Creative Services.\/STFC – UKRI<\/p>\n
Researchers have attempted to detect the 21cm line before. However, it is difficult to do using Earth-based instruments. Not only is the signal very weak but human-made technology \u2013 from FM radios to plane communication \u2013 can cause interference. Writing in the journal Nature Astronomy<\/a>, de Lera Acedo and colleagues said other challenges iincluded disturbances created by the Earth\u2019s ionosphere.<\/p>\n While experts at the EDGES (Experiment to Detect the Global EoR Signature) radio telescope in Australia have claimed to have found the 21cm line, questions have been raised over the results.<\/a><\/p>\n The team behind the CosmoCube mission, which is expected to last two years, said taking observations from the far side of the moon should avoid many of the challenges faced by Earth-based instruments.<\/p>\n \u201cThe total cost is estimated to be just under \u00a350m and the launching date \u2013 we expect it to be about five years from now,\u201d said de Lera Acedo, adding that CosmoCube has already been granted more than \u00a32m of funding by the UK Space<\/a> Agency.<\/p>\n Phil Bull, a professor of cosmology at the Jodrell Bank Centre for Astrophysics who is not involved in the project, welcomed the mission.<\/p>\n \u201cThe CosmoCube measurements will help us understand the major ingredients of our cosmic origins \u2013 the processes that led to the formation of the first stars and galaxies, and lit up the Universe after a period called the cosmic dark ages,\u201d he said.<\/p>\n But, Bull noted CosmoCube was not the only mission trying to make these measurements, and others might get there first.<\/p>\n \u201cMore ominously, other planned lunar missions might bring with them exactly the type of human-generated radio noise that the mission is trying to escape,\u201d he said, \u201cmaking this a race against time.\u201d<\/p>\n