Meet the Indian researcher uncovering clues to the formation of the galaxies

Kanak Saha doesn’t remember when he started counting stars as a hobby. He became fascinated by the heavens “around the age of 12”, he says.

Born to an onion and potato vendor in Dinhata, in West Bengal’s Cooch Behar district, he grew up with few luxuries. The clear skies of Dinhata and its small public library shaped his childhood.

“One of my teachers introduced me to the local library and a local science club where I was the only school student,” Saha says. “There we had an arrangement to watch the night sky with a telescope. It was one of the most fascinating experiences of my life to be able to see the stars and planets so clearly.”

In college, Saha picked physics so he could “get close to astronomy”. He graduated from Kolkata’s Scottish Church College in 1999, then signed up for a post-graduate degree at Banaras Hindu University. He was still struggling with finances. In fact, at one point in college, when he asked a professor if he could discuss pursuing a PhD, the latter dryly suggested Saha find a way to feed himself first.

Saha eventually got that PhD, in astrophysics, from the Indian Institute of Science in Bengaluru. He is now an associate professor at the Inter-University Centre for Astronomy and Astrophysics in Pune. And he is credited with discovering the galaxy AUDFs01, situated 9.3 billion light years away — and the first known distant galaxy emitting extreme-ultraviolet light.

This is a major development in a field where light is almost the only clue available to those trying to formulate theories about the formation of the earliest stars.

“The first galaxies were formed with massive stars that were mostly hydrogen and almost no metal. These stars would explode and the theory was that they would radiate extreme ultraviolet light. Though the galaxy we found is not one of the first, we spotted extreme ultraviolet light coming from it, which reaffirms the direction that we are all working in,” says Saha, 44.

It took the astrophysicist two years, from 2016 to 2018, to process his raw data and then two more years to study the galaxy in detail before he could finally share the discovery with the world. As he’d expected, it caused ripples, and has won him an Astronomical Society of India award.

Though research like this can be a solitary pursuit, Saha says a lot of his work thankfully involves interacting with others as a research mentor, hosting workshops and collaborating with scientists across India and around the world.

The pandemic year hit that last bit hard, though, halting all travel. Saha was particularly disappointed when he had to postpone his visit to Santiago, Chile, which has some of the largest ground-based telescopes in the world.

Before the pandemic, he enjoyed travelling to observatories in cities such as Paris and Cape Town. “The trip to South Africa in 2017 was tremendous. It seems strange for an astronomer to say this but the sky was unbelievably full of stars. Almost scary in a way that you felt it could consume you,” he says.

For children fascinated by the stars, he suggests pairing their passion for the night sky with a good academic base. “A good foundation in physics or engineering is a must if one wants to pursue a career in astronomy,” Saha says.

Schools need to play a role by making the pursuit of science more enjoyable and less tedious, he adds. “With just a basic tool like a telescope, schools could play a crucial role in building that foundation.”