Children's nonfiction about Indian science, history, and how we know what we know.

Children's nonfiction · Ages 10–14 · Out now

The Sky Was Their Screen

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.

“…more like a fun adventure than a lesson.”A young reader · Verified Amazon review
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Cover of The Sky Was Their Screen: a boy lying in a field at night under a ring of the twenty-seven nakshatra symbols, a temple on the horizon.

The book

A book about how people knew things, not just what they knew.

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.

  • Ages10–14
  • Extent104 pages, full colour
  • ScientistsLagadha, Aryabhata, Varahamihira, Brahmagupta
  • Inside27-station sky map, tear-out cards, activities
  • IllustrationSketches by Kavya

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.

Buy the book

On Amazon in Australia, the USA, Canada, the UK, Europe and Japan. The link opens your own country’s store. India edition coming soon.

Who's inside

One sky, handed down like a baton.

Each scientist inherited a question, pushed it further, and passed it on. The book calls it the relay road.

THE VEDANGA JYOTISHA ERA

Lagadha

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.

BORN 476 CE

Aryabhata

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.

c. 505–587 CE

Varahamihira

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.

BORN 598 CE · WROTE 628 CE

Brahmagupta

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

Write your birth year the way Aryabhata wrote numbers.

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

Five pages from the book.

An activity, a story, the 27-station sky 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

Things to cut out, write in, and take outside.

27-station sky map

All twenty-seven nakshatras on one two-page wheel, so a reader can find them from a backyard.

Shadow compass

Build a shanku yantra from a stick and a flat surface, and find true north the way it was found.

The akshara grid

The letter-number table, laid out by where each sound is made in the mouth — including the nose column.

Stump the Adult

Tear-out cards. Every question has an answer in the book, and most adults don't have it.

Sky Journal

Pages for recording what was actually seen, on which night — the habit the whole book is built on.

Badges & quests

Each completed observation earns a badge on the wall. Finishing the book means having done the work.

The spine of the book

Six ways to know something is true.

Ancient Indian thinkers 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.

Way 1

Pratyaksha

prah-TYAK-sha

Direct Observation

You see it, hear it, measure it, or experience it yourself.

In the bookMarking the tip of the Shanku’s shadow; watching a star shift position across two nights.

Way 2

Anumana

a-nu-MAH-na

Inference

You reason from what you observed to what must be true.

In the bookIf two shadows have different lengths at the same time, the Earth between them must be curved.

Way 3

Upamana

u-pa-MAH-na

Comparison

You understand something by comparing it to a similar pattern in something else.

In the bookSeeing the same triangular number pattern in poetry, combinations, and the sky.

Way 4

Arthapatti

ar-tha-PAT-ti

The Only Explanation That Fits

Several facts are true at once, and only one explanation makes them all agree.

In the bookAryabhata’s spinning Earth explains the star motions, eclipse calculations, and shadow measurements better than any rival idea.

Way 5

Anupalabdhi

a-nu-pa-LAB-dhi

Knowledge from Absence

The absence of something tells you something important.

In the bookThe moment a changing shadow stops changing marks the solstice; a balance of fortune and debt leaves zero.

Way 6

Shabda

SHAB-da

Reliable Received Knowledge

You learn from trusted knowledge passed forward by other people.

In the bookThe methods in these chapters survived because observers, scholars, and texts carried them across generations.

Modern science still depends on these same habits. Scientists observe. They infer. They compare. They test explanations. They learn from what is missing. They build on trusted work that came before them.

The Sanskrit names are ancient. The habits are still alive.

What readers say

It wasn’t like most science books that just tell you facts… That made it feel more like a fun adventure than a lesson.

My favourite part was learning about Aryabhata and how he explained eclipses. I also liked that the book has activities you can actually try yourself, so you’re not just reading the whole time.

★★★★★
A young reader, posted by her dadVerified Amazon purchase

Read all reviews on Amazon

Buy the book

On Amazon in Australia, the USA, Canada, the UK, Europe and Japan. The link opens your own country’s store. India edition coming soon.

Parents & teachers

Where it fits.

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

A shaft of light through a stone window.

Every Makara Sankranti, at the Gavi Gangadhareshwara cave temple in Bengaluru, sunlight passes through a stone window and falls exactly on the Shiva linga. 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.

Sandesh Krishnaveni, holding a helmet beside a motorcycle.

What's next

The road keeps going.