Episode 61: How scientists caught the heaviest black hole merger ever seen

Host: Subhra Priyadarshini; Sound editing: Prince George

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Hello and welcome to This Week in India’s Science. I’m Subhra Priyadarshini and today we journey from the depths of space to the cells of the ageing body — with a stop at a beetle lab in Delhi and a COVID toolkit in Varanasi.

First, we start with the story of the most massive black hole merger ever detected.

Earlier this month, astrophysicists announced that they have detected a cosmic whisper called GW231123 ripple across the universe. What made it extraordinary? The two black holes that collided were 137 and 103 times the mass of our Sun — firmly within a so-called “mass gap,” where, according to theory, black holes shouldn't even form.

It was a landmark moment for astrophysics — and for Debnandini Mukherjee, a gravitational wave scientist and a postdoc researcher at the University of Birmingham, one of the people who made the detection possible.

Debnandini Mukherjee: What’s remarkable is that both black holes lie within a mass gap of 60–130 solar masses, a range where we don’t expect black holes to form through normal stellar collapse. Also, both black holes seem to be spinning near the maximum rate allowed by physics, which makes this event even more unusual.

She works with the LIGO–Virgo–KAGRA collaboration, one of the largest scientific teams on Earth. Events like this merger challenge our understanding of how black holes form.

Debnandini wrote a social media post in which she hinted that the culture around such big science might warrant some change to recognise those who work on the frontlines. With hundreds of co-authors listed alphabetically, individual contributions often go unnoticed — especially for women and early-career scientists.

Debnandini Mukherjee: Big collaborations list all authors alphabetically, so even if you lead the work, you won’t be singled out in the author list. That makes visibility a real challenge. For women and minorities, it’s even harder. We’re fewer in number, especially in astronomy and astrophysics, and historically, our contributions have been overlooked. That affects networking, recognition, and even confidence.

What Debnandini suggests is clearer attribution practices and safer, more inclusive workplaces. Because behind every cosmic discover, there is someone debugging at 3 am.

Read about authorship in mega-science, the need to amplify women’s roles in astrophysics and what it takes to catch a whisper from the cosmos, in an interview with Debnandini Mukherjee this week on Nature India.

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From the cosmos to the coronavirus. In Varanasi, researchers have built a computational tool that explains how the SARS-CoV-2 virus keeps slipping past antibody treatments.

Aditya Padhi: This gives us a molecular-level map of how the virus outsmarts certain antibodies. Also, importantly, how wemight outsmart the virus in return. It opens a path to engineering more resilient therapies against current and future pathogens.

That’s Aditya Padhi, from Indian Institute of Technology Varanasi. His team found that mutations in the spike protein’s receptor binding domain — the very place sotrovimab latches onto — are altering the protein’s shape, weakening the drug’s grip.

The collaboration, which included scientists from Shillong and Guwahati, shows how digital models can pre-emptively track viral resistance — potentially staying one step ahead of the next variant.

We have a research highlight on this in Nature India this week.

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Next, we zoom in on something smaller — the red flour beetle. In most kitchens, it’s a pest. But in a Delhi lab, it’s a window into how our immune systems evolve under stress.

Evolutionary biologist Imroze Khan at Ashoka University and colleagues pricked over 165,000 beetles by hand, across 30 generations. They wanted to see what happened when they’re infected by fast and slow bacteria — alone or together.”

The results? When beetles faced a slow-growing pathogen, they adapted. But the fast-growing one overwhelmed their systems. And when both hit at once? The beetles struggled to evolve resistance to either.

Coinfections are the rule, not the exception — in people, livestock, and wildlife. This study helps us understand why vaccines sometimes fail to produce lasting immunity.”

RNA sequencing showed that the beetles’ immune responses were skewed — as if the fast pathogen was hijacking the system.It’s a cautionary tale in the age of zoonotic outbreaks and antibiotic resistance. Fast pathogens don’t just spread — they sabotage.

Read about this research on Nature India this week.

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Finally in this episode, India is ageing — fast. By 2031, over 100 million Indians will be 70 or older. But a key to ageing well may lie in something surprisingly simple: muscle. “Muscle is a metabolic organ. It regulates glucose, inflammation, even brain health. And in India, we’re losing it too fast.”

Arvind Ramanathan the Institute for Stem Cell Science and Regenerative Medicine (inStem), Bengaluru argues that muscle mass should be at the heart of India’s public health strategy. He points to a staggering fact — grip strength is a better predictor of all-cause mortality than blood pressure.

Sarcopenia, or age-related loss of skeletal muscle mass and strength, has a diagnostic code globally. But in India, it’s invisible. In Vellore, 40% of older adults already qualify as sarcopenic. And the consequences could be deadly.

So what’s the solution? A muscle-centric ageing model: strength clinics, better diagnostics, protein-focused diets — especially for women, who are more vulnerable to muscle loss.

Ramanathan says it is time to shift from a healthcare system that reacts to ageing — to one that prevents decline before it begins. Read a comment on this by Ramanathan on Nature India this week.

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That’s all for this week’s episode of This Week in India’s Science. From black holes to beetles, COVID to core strength — science is reshaping how we understand health, evolution, and the universe itself.

You can find links to the studies and voices you heard today in the show notes. I’m Subhra Priyadarshini. Thanks for listening. Until next time.