Solar System – Hanuman is swinging joyfully from vine to vine in the Kishkindha forest when he stops mid-swing. Below him, resting against a banyan tree, is a massive figure. Hanuman: Acharya Jambavan! He drops, landing softly in front of the old bear king.

Jambavan: How are you, Anjaneya? It has been a long time since I saw you last. Hanuman: It feels like ages. I haven’t forgotten your amazing palace.

But I haven’t come empty handed. He produces a large leaf platter piled high with glistening berries and nuts. In the centre sits a glowing golden jar.

Hanuman: The world’s tastiest berries. This jar is Manuka Honey, which I asked my celestial father Vayu to bring from New Zealand.

Jambavan’s eyes sparkle. He dips a large claw into the jar and tastes it. Jambavan: Divine! The texture, the richness.

Anjaneya, you know the way to an old bear’s heart. Jambavan begins eating the fruits. Hanuman watches, his tail twitching with suppressed curiosity.

Jambavan: What is troubling you? Your tail is vibrating like a hummingbird’s wing. Speak.

Hanuman: Since I visited your home, I’ve been meaning to ask you. Your palace has seven distinct buildings but why are they arranged in a stretched-out oval shape and with such crazy weather changes inside the same complex? Jambavan (chuckles): I am a great admirer of the cosmic architects, Lord Vishwakarma and Lord Brahma.

I travel to different worlds, observing their brilliant structures of galaxies and star systems. My palace is a humble tribute to the architecture of our own Solar System. Hanuman: Our Solar System looks like a stretched-out oval? Jambavan: The paths within it do.

Tell me, how do you think Earth moves around the Sun? Hanuman: Well, in the future, the early Geocentric Theory astronomers will propose the Earth is in the centre, right? Jambavan: Correct. Then will come brilliant observers like Copernicus and Galileo who propose the Heliocentric Theory: the Sun in the centre. Hanuman: Right.

So, the Sun is in the middle and the Earth goes around it in a circle. Like a ring! Jambavan: Not quite. Copernicus got the Sun-in-the-centre part right but not the shape of the path.

That was corrected by Johannes Kepler, a brilliant mathematician. Kepler’s First Law is “All planets move around the sun in elliptical orbit with the sun at one of the foci”. So, the planets move in ellipses, not circles.

Think of it as a flattened stretched-out circle. Hanuman: Okay, but what does that have to do with the weather in your palace? Jambavan: Because of the elliptical path, a planet is sometimes closer to the Sun, and sometimes farther away. So, in my palace, the buildings on the “close” side of the oval have hot weather and those on the farther side have cold weather.

Hanuman: That makes sense. But a circle is easy to draw.

How do you draw an ellipse? Jambavan (smiles): Get me some strong vines and two sharp sticks and I’ll show you the secret of celestial mechanics. When Hanuman returns with the supplies, Jambavan jams the sticks into the soft earth, about two feet apart. Then, he ties the vine into a closed loop and drapes it over the sticks.

Jambavan: These two points are the foci. In a circle, there is only one centre. An ellipse has two.

In our Solar System, the Sun sits at one point. The other is empty space. Now, put your drawing stick inside the loop and pull it tight so that you make a triangle.

Hanuman pulls the loop taut away from the two centre sticks. Jambavan: Excellent.

Now, keep the vine tight, and drag your stick all the way around the two centre sticks and draw the path. Hanuman carefully moves his stick around. Because the vine is looped around two points instead of one, the resulting shape he draws in the dirt is not a perfect circle.

Hanuman (stares at the ground): Look at that! It works! Jambavan: If you move the foci — the two centre sticks — closer together, the ellipse will look more like a circle. If you move them further apart, it will become very flat. Hanuman: So, the Earth swoops in close to the Sun and then flies far away.

Jambavan: It is the celestial dance of gravity. When the planet is closest, it moves faster. When further away, it is slower.

Hanuman: Your palace makes sense now. The seven buildings move through seasons based on their elliptical position. But right at the centre of your palace – at the focus point – there was a mysterious eighth structure that glowed and hummed.

What was that? Jambavan (smiles mysteriously): That is the heart of the design. It is an artificial sun that generates heat, light and power for the entire palace complex.

Hanuman’s jaw drops. His eyes widen to the size of saucers.

Hanuman (jumps up): Wow! How is that even possible? A sun is a huge ball of burning gas. How do you fit one inside a building? Jambavan opens his mouth but, suddenly, a thunderous sound echoes through the clearing. He looks mournfully at the empty jar of honey.

Jambavan: I am famished. Let me find some jackfruit first, then I will tell you all about it.

Jambavan lumbers off into the forest, as Hanuman chases after him shouting questions. Create an ellipse You need: Cardboard; two push pins, string and a pencil Method: Push the pins into the cardboard at a distance from each other. Now loop the string over both the pins (the two foci).

Now draw the loop taut with your pencil and draw the shape. See how changing the distance between the pins changes the shape of your orbit.

The author is the founder and CEO of Vaayusastra Aerospace, an IIT-Madras IC graduated ed-tech company, and a Ph. D.

research scholar in Education at NITTTR.