Children's nonfiction · Ages 10–14 · Out now
How ancient Indian scientists read the universe
Four scientists, watching the same sky across two thousand years — and the six tests they used to decide whether something was actually true.
The book
Most science books for children hand over the answer. This one hands over the method. Every chapter follows one scientist to the moment they had to prove something — with a shadow, a syllable, a count of days — and then asks the reader to try it themselves, outside, with what's in the house.
Sourced from scholarly work, not summaries — including Kim Plofker's Mathematics in India and Bimal Krishna Matilal on the pramanas. Where historians disagree, the book says so.
Who's inside
Each scientist inherited a question, pushed it further, and passed it on. The book calls it the relay road.
Set down the oldest surviving Indian text on keeping time by the sky — the rules for fitting the moon's months into the sun's year, so a festival lands on the right day every year, forever.
Wrote numbers as syllables so entire tables could be memorised, and argued that the sky doesn't spin around us — we turn. He explained eclipses with shadows, and the maths that followed him carried his name for a thousand years.
Built a system for prediction — collecting, comparing and testing what earlier astronomers claimed, and keeping what survived the test. The book's chapter title: the man who built a system to predict the sky.
Wrote down the rules for working with zero and with numbers below nothing — debts, in his words — and set them out as verse a student could learn by heart. The first book ends here, in 628 CE.
Try it yourself · from Chapter 2
He didn't put digits on the page. He used letters, arranged by where each sound is made in your mouth — so a whole table of astronomical values could be carried in memory and recited. Here's your year in that system.
Look inside
An activity, a story, the gatefold map, a page for recording what you saw, and the framework the whole book is built on. Tap any page to read it full size.
Tap a page to enlarge
Inside the pages
All twenty-seven nakshatras on one fold-out spread, so a reader can find them from a backyard.
Build a shanku yantra from a stick and a flat surface, and find true north the way it was found.
The letter-number table, laid out by where each sound is made in the mouth — including the nose column.
Tear-out cards. Every question has an answer in the book, and most adults don't have it.
Pages for recording what was actually seen, on which night — the habit the whole book is built on.
Each completed observation earns a badge on the wall. Finishing the book means having done the work.
The spine of the book
Indian philosophers argued for centuries about what counts as knowledge, and settled on six tests — the pramanas. Each chapter opens one, and asks which ones the scientist leaned on. By the end, a reader has all six.
You saw it yourself.
You reasoned it out from something you did see.
You recognised it by comparing it to something known.
It's the only explanation that makes the rest make sense.
You know it's absent because it isn't there to be found.
Someone trustworthy told you — the only one you don't do yourself.
Parents & teachers
Written for ages 10–14 and read-tested with children that age, whose feedback shaped the revisions. It suits a curious reader working alone, a parent reading alongside, or a classroom unit on astronomy, number systems, or history of science. No prior knowledge of Sanskrit or Indian history is assumed — Sanskrit words are introduced with a pronunciation system built for readers who've never seen the script.
A note for adults, the full source list, and the activity list appear in the back matter. For school orders, review copies, or a visit, get in touch below.
Where it started
Every Makara Sankranti, at the Gavi Gangadhareshwara cave temple in Bengaluru, sunlight passes through a stone window and falls exactly where it is meant to fall. Somebody worked that out — the angle, the day, the geometry of a hill — and cut it into rock so it would keep working centuries later. This book began with wanting to know who, and how.
Sandesh Krishnaveni writes children's nonfiction about Indian science and cultural heritage. He lives in Sydney and works in IT.
He writes under the pen name Kritansha — short for Krishnaveni tanaya Sandesha, a name woven from his mother's, Krishnaveni, and his own. Hers comes first, as the beginning of everything that followed.
When he isn't writing, he is usually thinking about motorcycles.
What's next
The sequel picks up after 628 CE and takes the sixth way — the trusted word — as its whole subject. Every chapter asks one question: what do you do when the trusted word turns out to be wrong? Bhaskara II, the Kerala school, and Jai Singh II's stone instruments.
The Sky Was Their Screen is the akasha book — sky and number. Four more are planned, one for each remaining element: bhoomi, vayu, agni, jala. Earth, air, fire, water.
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