Opinion Express View on the universe’s background hum: Listen to the cosmos

If two black holes collide in the dark loneliness of space, a long long time ago, far far away from this corner of the galaxy, do they make a sound? Albert Einstein thought so when he postulated the existence of gravitational waves, “ripples” that show that large bodies affect the very fabric of space-time. A century later, in 2015, the first faint notes of the “hum of the universe” were picked up, proving Einstein’s theory. This week, Pulsar Timing Arrays (PTAs) around the world — including in India — “heard” gravitational waves that scientists believed originated about 8 billion years ago. These waves are caused, simply put, by the mergers of large Black Holes. Over time and space, these waves have gathered, and now, picked up by radio telescopes on the third rock from the sun.

For the layperson — and perhaps even the astrophysicist — there is something awe-inspiring, to the point of provoking existential dread, about the sheer scale of the bass tones that are being heard. The celestial bodies that have collided are too large to be comprehended, except through abstraction — in essence, maths. It was eight billion years ago that the black holes collided, absorbing everything including light. This confrontation with the vastness of the cosmos, and the inevitable realisation of how all of human existence is barely a flicker in the heavens, makes the worries, hopes, dreams and desires of homo sapiens seem pointless.

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What is the point of art, love, jobs, family, poetry when it pales against the rich song of all that went before? Maybe the existentialists and nihilists were always right. But then, it took just a little over a century — from Einstein to PTAs — for humans to become the only known species in the universe to hear the songs of the stars. Sometimes, being an audience is purpose enough.