In Huancayo, which in Quechua means "place of stones" there is an observatory to look at the sky and beyond. Valeria loves the observatory, because it is like an open window to the universe.

Sometimes after school Valeria goes for a walk to the Torre Torre stone forest, known as “hoodoos”, to look at the rocks and imagine she is on Mars.

Fernanda knows that plants convert water, carbon dioxide, and sunlight into glucose and oxygen. This is how they feed and grow. They also purify the air. Summer vacations and melting glaciers are made of water and sun. Also the rainbow.

Fernanda observed that the stream that runs past her aunt's house was full of tilapias and nearby the vegetation was greener, taller and more luxuriant. Tilapia have a large appetite and are sometimes used to control algae or mosquito pests.

For a seed to germinate, many things are needed, although in reality these can be summarized in three: water, sun and air.

Follow the water is the phrase that guides NASA explorers on Mars. Following the water is another way to find the mysteries that make life possible.

The Sun sometimes looks red and sometimes looks orange and almost all young children draw the sun yellow. What color is it really?

Fernanda decided to take the water from the stream, where the tilapias live, to her house and make a garden. Their hypothesis is that tilapia droppings can be a good fertilizer for plants.

Turtles and snails love vegetables, but Fernanda has observed that they do not eat the plants watered with the tilapia water. Why is it?

When Valeria goes to the cave of Huagapo, one of the deepest in South America, among the rocks she imagines the texture of a Martian landscape. A Martian landscape is also a way of referring to everything that we do not understand or do not know, to that which seems distant or incomprehensible to us.

A herd on the road from Huancayo to Huayllay. 65 million years ago, in the Cenozoic era, there were volcanoes in Huayllay. Today what remains is a forest without trees, a forest of stones.

Why do plants grow on Earth and we don't know anything about plants on other planets? If we decided to live elsewhere in the galaxy, we would have to bring plants because we depend on them to breathe. Would plants be green in space?

In Huancayo there is a Cachipozo, a salt water spring. Valeria extracts microorganisms from there because she thinks that if there are some bacteria that survive on Earth in conditions similar to those of the environment on Mars, then it is possible that they will also survive on that planet.

It is difficult to walk with a microscope under your arm. Scientists created one out of paper. With it, it is possible to identify larvae of some plague, catalog Amazonian insects, classify pollen. These are grains of salt seen through this paper microscope, to which a lens was adapted to be photographed with a cell phone.

Cyanotype of oregano leaves, harvested from the Fernanda garden. There are many ways to observe and record. Before we had cameras on phones, before we had cell phones, there was cyanotype.

If Valeria and Fernanda went to live on Mars, what would they eat? Where would they find water? Could they take Luna (moon), Valeria's cat? The planet Mars, by the way, has two moons: Phobos and Deimos.

All things are made of atoms, and atoms are made of positive and negative charges. Sometimes a body is charged with static electricity, and when it comes into contact with another body of a different charge, there is an exchange of energy and a spark or a lasting friendship is created.

Some nights, Fernanda and Valeria raise their faces to the sky and, if the sky is clear, they can see one, two, three, four hundred stars. Or rather, the glare of those stars that may have died long ago. They are light years away and without falling thanks to gravity. Surviving on Earth, in that stardust that we are made of.