Scientists plan to launch a suitcase-sized satellite called CosmoCube into lunar orbit to detect faint 21cm radio signals from the universe’s cosmic dark ages. Backed by the UK Space Agency, the roughly £50m mission aims to bypass Earth’s atmospheric interference by utilizing the radio-silent far side of the moon.
Researchers are preparing to peer into the universe’s infancy by utilizing a unique vantage point in space. A proposed mission centered around a compact satellite named CosmoCube aims to shed fresh light on the period shortly after the Big Bang by listening for faint signals from the cosmic dark ages.
Targeting the 21cm Line from Lunar Orbit
The mission focuses on detecting the radio frequency signal emitted by neutral hydrogen atoms, known as the 21-centimeter line or H-line. As this ancient signal travels across billions of years, its wavelength stretches or redshifts, providing researchers with a way to track its strength relative to the cosmic microwave background radiation.
Prof Eloy de Lera Acedo of the University of Cambridge’s Cavendish Laboratory, lead author of the study published in Nature Astronomy, explained how the signal functions. The main thing we track by looking at this signal is what’s the physical temperature of the gas during the early universe,
he said, noting that the temperature is affected by contemporaneous cosmic events.
By using the signal as a cosmic thermometer, scientists hope to study events spanning from 380,000 years after the Big Bang through the cosmic dawn—when the first stars and galaxies emerged—up to the end of the epoch of reionization approximately one billion years later. Researchers also expect the amplitude and shape of the signal to carry signatures of dark matter, offering a window into how hydrogen was pulled together to form the earliest stars.
Why Researchers Need the Far Side of the Moon
Detecting the 21cm line from Earth has proven exceptionally difficult. Ground-based instruments must contend with weak signal strengths, radio interference from human technologies like FM radios and plane communications, and distortions created by the Earth’s ionosphere.
While researchers at the Edges radio telescope in Australia previously claimed to detect the signal, those results faced scientific questions. CosmoCube bypasses these terrestrial hurdles entirely by leveraging the physical mass of the moon itself.
For roughly 40 minutes during each two-hour orbit, the moon will block interference from Earth, giving the spacecraft a clear window to sweep the cosmos.
Funding, Timeline, and a Race Against Lunar Congestion
The entire mission carries an estimated price tag of just under £50m. The UK Space Agency has already awarded the project more than £2m in initial funding, and researchers anticipate a launch roughly five years from now.
Measuring about the size of a small carry-on suitcase, CosmoCube is designed to collect roughly 1,000 hours of observations across a planned two-year lifespan. Aside from the science, what makes our mission unique is its size: we’re probing the earliest, deepest parts of the dark ages that others don’t reach, but with a compact, relatively low-cost platform,
de Lera Acedo noted.
Yet the mission faces an unexpected ticking clock. Phil Bull, a cosmology professor at the Jodrell Bank Centre for Astrophysics who is independent of the project, pointed out that CosmoCube is not alone in targeting these measurements.
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