What is a star?

Understanding in depth what is a star is a question that kept busy the brightest minds throughout the centuries. Today we’re going to unveil everything you need to know about what makes a star shine and why they are so important for life on earth.

Star shine: an ancient question

In Ancient Greece, the astronomical observations efforts went to designing a calendar useful to organize harvesting seasons. Homer’s Odyssey, for example, has explicit references to constellations such as Ursa Major and Orion; he even describes how stars can be useful for sailors and navigation.

Nowadays, we use telescopes; we have the Mars exploration Program active and physics have made it clear that the universe is in constant expansion.

 

But, What is a Star? A scientific approach:

A star is a massive sphere of gas and particles. Some might even say that we are stardust. This is because the supernova explosion remainings are the sediments that will create new stars and new planets. How does this happen? Gravity acts over that gas, drawing it towards the interior of the new star forming a nucleus. With the right amount of pressure, this causes a burst of energy.

 

In this way, a series of chain reactions occur releasing energy in the form of electromagnetic radiation, light, and heat. Therefore, when looking at the sky, we see the energies of the cosmos acting, physics and chemistry playing in a volatile and unstoppable symphony at millions of light years of distance. But, from the earth, we can only perceive beautiful and shiny dots, blinking from above.

 

What is a star made off? Hydrogen

The hydrogen fusion process takes place within a star nuclei’s. We understand that the answer to what is a star made off comes from the nuclear fusion, a chemical reaction that consists in the star slowly running out of hydrogen and transforming it into Helium.

 

This chemical process goes further creating numerous elements, at least until the hydrogen runs out completely. When converted into helium, each gram of hydrogen releases about 200,000 kW / h. The Sun, our nearest star, burns about 600 tons of hydrogen per second. However, according to calculations, it will keep shining for at least 5000 millions of years.

 

Twinkle Twinkle Little Star

More than a children’s lullaby, what is a star and their shine will amaze you believe it or not. But, not only because it’s important to know what is a star; but also because it is possible to tell them apart.

 

There are several classification systems. For example, the one established by the International Astronomical Union in 2006 takes into account whether the stars have a gravitational center or not, that is, if they constitute a star system:

 

• When the stars form a system, they are called systemic.
• If there’s no gravitational center, they are classified as solitary stars.
• In turn, the systemic stars are divided into central if they represent the gravitational center for other stars, while the systemic satellite stars are those that orbit around others.
• There are also stars that are part of a planetary system, with different celestial bodies such as planets and asteroids orbiting around them.

 

Counting stars:

The great pressures and temperatures enumerated in this article on what is a star could result in a desolate and unfertile panorama. However, there’s where it lies the spark of life.  Some have called it the Big Bang.

We all know the sun makes life on earth possible, but we can also find an answer to many other questions in the sky. Some might even resort to astrology and succeed. Whether they are Supernovas, constellations, red giants or white dwarfs, the starry sky will always be full of mysteries, but also full of answers.