How do we know when the Sun will burn out? Astrophysicist Julieta Fierro has the answer

How do we know when the Sun will burn out? Astrophysicist Julieta Fierro has the answer

Students in Middle School had the opportunity to talk to one of Mexico’s most renowned scientists, Julieta Fierro, to discuss the importance of science and to dive into some of the most existential questions that have arisen in science.

Julieta started her presentation with a bold statement: “science makes mistakes all of the time”. She then proceeded to explain: we do not learn until we go and do it. You have to go in and create experiences for yourself and make mistakes. But even then, scientific knowledge is not unquestionable, and everything we think we know, we do not truly know or understand to its full capacity. What we think we know might, in fact, be a mistake.

One of the most fascinating “facts” Julieta shared was that nowadays, modern physics studies quantum mechanics because humans have realized that all knowledge can be questioned and it depends on the conditions that surround it. So whatever “fact” we think cannot be questioned, can, in fact, be. Scientists have concluded that knowledge is about probability and nothing is 100% true in every scenario.


Captivated by this information, the Students started asking questions to make sense of what she had just taught them. Some of these included: What reveals more to general knowledge, studying the universe or studying the atoms? How do they calculate the probability of life expectancy? What is the probability of aliens existing on other planets?

Using props and students as examples, Julieta managed to answer all of their questions, which was very much a demonstration of why sharing scientific information is important. It is thanks to this that we can have an answer for inquiries such as when the sun will come to an end or  burn out:

Scientists collect information on the materials and quantities of elements that the Sun has on its surface. Running this information through a computer, humans are then able to calculate that the sun has enough fuel for another 5.5 billion years.

Of course, this is all just a probable scenario, because we never know something else might happen that could end up destroying the Sun... will we ever know the true answer?

About Julieta Fierro

Julieta is an awarded astrophysicist who currently holds a position at the Autonomous University of Mexico as a researcher at the Institute of Astronomy, in the Area of Scientific Publication. She also works as a teacher in the Science Division. Her kids studied at ASF, the main reason why she holds our school so close to her heart. If you want to contact Julieta to discuss any of your astronomic doubts, you can contact her at