Why In News?

Astrophysicists are preparing next-generation satellite missions, including the UK-led CosmoCube and India’s PRATUSH, to orbit the Moon and capture the faint radio signals emitted during the dawn of the universe.

What is the Cosmic Dawn?

Cosmic Dawn is the period in the early universe, roughly 50 million to one billion years after the Big Bang, when the very first stars, black holes, and galaxies formed.

Key Features of Cosmic Dawn

  • End of Dark Ages: It marked the end of the "Cosmic Dark Ages," a long stretch when the universe was filled with a thick, neutral gas fog and lacked starlight. 

  • First Light: The ignition of these early stars emitted ultraviolet radiation that lit up the universe for the first time with a glow other than the leftover heat of the Big Bang.

  • Reionization: The intense light from these first objects began the Epoch of Reionization, breaking apart neutral hydrogen atoms into protons and electrons.

What is PRATUSH?

PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen) is a dedicated Indian cosmology experiment conceptualized and engineered by the Raman Research Institute (RRI), Bengaluru, in partnership with ISRO.

Lunar-Orbiting Observatory: Unlike ground-based instruments, PRATUSH is designed to operate in an orbit around the Moon, taking scientific measurements while flying through the radio shadow on the lunar far side.

Precision Wideband Spectral Radiometer: The payload consists of an ultra-sensitive analog receiver, an electrically small dipole antenna, and digital spectrometers calibrated to capture signals between 30 MHz and 250 MHz.

Building on the SARAS Legacy: Leverages design heritage from RRI's terrestrial SARAS (Shaped Antenna measurement of the background RAdio Spectrum) experiments, which refined spectral calibration in remote environments such as Ladakh.

Targeting Global Cosmological Breakthroughs: Aims to measure the sky-averaged (global) 21-cm signal to identify the epoch of early stellar ignition with high signal-to-noise fidelity.

What is CosmoCube?

CosmoCube is a low-frequency radio astronomy mission concept spearheaded by astrophysicists from the UK, supported by the Royal Astronomical Society (RAS) and international partners.

Targeting the Far-Side Radio Shadow: Sending a compact satellite into lunar orbit to collect low-frequency radio signals when hidden from Earth-based transmitters.

Dedicated Low-Frequency Spectral Window: Focuses primarily on measuring cosmic radio emissions below 100 MHz, a spectral region inaccessible from Earth due to ionospheric distortion.

Searching for the Primordial Absorption Signature: Designed to confirm or refute conflicting ground-based claims regarding the Cosmic Dawn absorption trough through clean extraterrestrial observations.

Cost-Effective SmallSat Platform: Demonstrates how compact CubeSat architectures can carry out high-precision cosmological experiments in deep-space environments at reduced mission costs.

 

Source: THEHINDU

PRACTICE QUESTION

Q. Why is the far side of the Moon considered the most ideal location in the inner solar system for low-frequency radio astronomy?

A) It experiences zero gravity, allowing telescopes to float without mechanical structures.

B) The physical body of the Moon permanently shields it from human-made terrestrial radio frequency interference.

C) It possesses a dense magnetic field that amplifies incoming cosmic radio signals.

D) It remains in perpetual darkness, completely protected from solar radiation.

Answer: B

Explanation:

The Moon is tidally locked to Earth, meaning its far side permanently faces away from our planet. This geometric orientation allows the solid mass of the Moon to act as a natural shield, blocking human-made radio frequency interference (RFI) generated by terrestrial communications, radar, and broadcasting, while also being free of Earth's distorting ionosphere.