A Telescope the Size of a Continent
Imagine a telescope so large it couldn't be built in one place. That's the Square Kilometre Array (SKA), an ambitious international project to build the world's largest and most sensitive radio telescope. The SKA isn't a single dish, but thousands of
antennas spread across two remote, radio-quiet locations: South Africa and Australia. When fully operational, the SKA will be made up of hundreds of dishes and over a hundred thousand smaller antennas. This global collaboration aims to answer some of the most profound questions in science by observing the universe in ways never before possible. Its mission is to explore the unknown frontiers of science, from how galaxies form and evolve to the very origins of life.
The Indian Hand in a Global Giant
India is a key player in this monumental scientific endeavour, having been involved since the project's early days. In January 2024, the Government of India gave its formal approval for participation, committing ₹1250 crore to the construction phase. The National Centre for Radio Astrophysics (NCRA) in Pune coordinates the SKA-India consortium, which includes more than 20 institutes. Indian scientists and engineers have taken a leading role in designing the Telescope Manager system, essentially the nerve centre that controls the entire observatory. This involvement not only provides Indian astronomers with access to this world-class facility but also drives technological growth in fields like electronics and big data, with plans for a regional SKA data centre to be established within the country.
Listening to the Cosmic Dawn
One of the SKA's primary goals is to witness the 'Cosmic Dawn' — the era when the first stars and galaxies lit up the universe. After the Big Bang, the universe was a dark place filled with neutral hydrogen gas. The SKA is designed to detect the faint radio signals emitted by this primordial hydrogen before, during, and after it was 'reionized' by the light from those first stars. By linking thousands of antennas using a technique called interferometry, the SKA effectively acts as one enormous, incredibly sensitive telescope. This allows it to capture signals that have travelled for over 13 billion years, providing snapshots of a universe still in its infancy.
Rewriting the First Chapter of the Cosmos
Recent discoveries using SKA precursor telescopes, like South Africa's MeerKAT, have already shown the potential of this approach. Astronomers recently detected a faint hydrogen signal that travelled for billions of years, a major step towards creating detailed 3D maps of the universe's large-scale structure. The full SKA will take this much further. By mapping the distribution of hydrogen in the early universe, scientists can test and refine their theories about how the first galaxies formed and what they were like. These observations will help us understand the mysterious forces of dark matter and dark energy, which are believed to make up most of the universe. In essence, the SKA is a time machine that will allow us to read the universe's history as written in the language of hydrogen, potentially rewriting the first chapter of our cosmic story.
