From Moon’s far side, a satellite will hunt for universe’s first radio signal
Kochi: Cosmologists are looking to the far side of the Moon to listen to the universe’s earliest whispers — the faint 21-cm radio signal from the first stars and galaxies.
At the heart of this excitement is CosmoCube, a small satellite that scientists from the Royal Astronomical Society (RAS) plan to send to the lunar far side, which permanently faces away from Earth.
The 21-cm signal — emitted when neutral hydrogen undergoes a spin-flip transition, famously depicted on the Pioneer and Voyager plaques — is like a needle in a haystack. It is buried beneath foreground radio emissions thousands of times stronger, mostly from our own galaxy and human-made interference.
On Earth, isolating it is extremely difficult even for advanced platforms. That’s why the far side of the Moon is prized: it is shielded from Earth’s radio noise, offering a pristine, quiet environment for low-frequency radio astronomy.
CosmoCube will attempt to detect the faint signal to reveal how the first stars lit up the cosmic dark ages.
The challenge is similar for India’s PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen), a proposed lunar orbiter designed for the same hunt, underlining a new race to capture the universe’s first chapter from the Moon’s radio shadow.
