How We Found North in a Power Cut

The power cut hit the whole campsite at Bhandardara at about half past nine, just after the bonfire had been put out, and with it went the one phone that still had any battery left. Ours had died that afternoon from overuse of the selfie camera. Aarav’s went with the lights, because the torch app finished it off.

Our instructor, a quiet woman called Ms Kulkarni who had said almost nothing all week, asked us which way was north. Nobody knew. Someone pointed confidently at the lake. Someone else pointed at the toilets. Ms Kulkarni waited until we had finished arguing and then said, “Look up.”

Without the campsite lights the sky had filled up. She showed us the Saptarishi first, seven bright stars in the shape of a ladle, low over the hills. “Take the two stars at the end of the bowl,” she said, “the side away from the handle. Draw a line through them, upward, and go about five times as far as the gap between them.” There, on its own, was a star that wasn’t especially bright. “That,” she said, “is the only star in the sky that is not going anywhere tonight.”

We didn’t believe her, so she made us check. We each picked a star near the hills and lined it up with a tent pole. An hour later, while we sat around telling ghost stories in the dark, the stars near the hills had slid sideways or sunk out of sight. The Pole Star was exactly where we’d left it.

The reason, she said, is that the stars aren’t really moving. We are. The Earth spins once a day around an axis that runs through the North and South Poles, and from the ground that spin makes the whole sky seem to wheel around us, about fifteen degrees every hour. But the sky has to wheel around something. Extend the Earth’s axis out into space and it points at a spot in the northern sky, and by luck there happens to be a reasonably bright star sitting within a degree of it. Everything else circles that spot. Polaris, almost on it, barely moves at all. So whoever faces it is facing north.

Then she did something that I still think about. “Hold out your fist at arm’s length,” she said, “and put it on the horizon under the star.” We stacked our fists, one above the other, arms aching. It took about two. “A fist is roughly ten degrees,” she said. “So the Pole Star is about twenty degrees up. And we’re at about nineteen and a half degrees north of the equator. That is not a coincidence.”

She drew it in the dirt with a stick. If you stood at the North Pole, the Earth’s axis would point straight up above your head, and so would Polaris. If you stood on the equator, the axis would point along the ground towards the north, and Polaris would sit right on the horizon. Walk from the equator towards the pole, and the star climbs, one degree for every degree of latitude you cover. Sailors used exactly this for centuries: measure the Pole Star’s height and you know how far north you are, no map required.

Aarav, who had been sulking about his phone, said, “So we could find out where we are with just our hands.” Ms Kulkarni said yes, roughly, to within a few degrees, which on Earth is a few hundred kilometres. “Not good enough to find your tent,” she said. “Good enough to find your country.”

We found our tents by walking north to the lake, where we already knew they were, and then left a bit. The lights came back at midnight and instantly the sky emptied again, and I remember feeling cheated, as if somebody had switched the stars off rather than the other way round.