Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

How will the universe end? – Iez M., age 9, Rochester, New York

Whether the universe will “end” at all is not certain, but all evidence suggests it will continue being humanity’s cosmic home for a very, very long time.

The universe – all of space and time, and all matter and energy – began about 14 billion years ago in a rapid expansion called the Big Bang, but since then it has been in a state of continuous change. First, it was full of a diffuse gas of the particles that now make up atoms: protons, neutrons and electrons. Then, that gas collapsed into stars and galaxies.

Our understanding of the future of the universe is informed by the objects and processes we observe today. As an astrophysicist, I observe objects like distant galaxies, which lets me study how stars and galaxies change over time. By doing so, I develop theories that predict how the universe will change in the future.

Predicting the future of the universe by extending what we see today is extrapolation. It’s risky, because something unexpected could happen.

Interpolation – connecting the dots within a dataset – is much safer. Imagine you have a picture of........

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