Main Sequence Star: Our Sun's Thermonuclear Reaction

The sun is so massive that it’s 99.9% of the mass in our solar system.

But there was just enough behind for gravity to build up other things like our planets.

But how did the sun come into existence? And how much longer will the sun’s fire burn for?

Here are some of the essential sun facts.

How did the sun come into existence?

The sun is mostly hydrogen (74%) and helium (25%). It started with hydrogen bundling together and rotating.

Eventually, four hydrogen atoms connect with four electrons to create one helium atom through heat.

If you look at hydrogen on the periodic table, four individual hydrogen atoms have more mass than one helium atom.

According to Einstein, you can’t lose mass. But you can convert mass to energy. Stars are a thermonuclear reaction where four hydrogen atoms are put together into helium.

What is a main sequence star?

In our case, our Sun releases the energy that we see as sunlight on Earth.

So, it burns hydrogen into helium and releases energy.

Typically, stars go through this “main sequence” for about 95% of its life.

So for most of our sun’s life, it releases energy as sunlight through thermonuclear reactions.

How much longer will the sun’s fire burn?

Just like any fire, eventually fires burn out. Similarly, stars all have life spans. Heavyweight stars have the most fuel but burn it at the fastest rate.

The smallest stars live the longest at a minimum of 50 billion years. If you compare this to the universe, it’s only 13 billion years old.

Our Sun is 1 SM and is classified as lightweight. In the lightweight category, this means that it has a life expectancy of about 10 billion years.

Currently, we’re into 5 billion years for our Sun. It’s at the middle age of its life and has about 4 billion more years. It won’t become a supernova and will collapse into a white dwarf.

Other quick facts about the sun

Age: 4.6 billion years
Type: Yellow Dwarf (G2V)
Diameter: 1,392,684 km
Equatorial: 4,370,005.6 km
Mass:199 x 10³⁰ kg (333,060 Earths)
Core temperature: 13,599,726°C
Surface temperature: 5,500°C
The mass of the sun takes a 99.86% weight of the solar system.
It takes 8.3 minutes for sunlight to reach the Earth.
The average distance from the Earth to the sun is 149.6 million kilometers.
The sun is mostly Hydrogen (74%), Helium (24%), Carbon (15%), Other
Composition of the Sun: Corona, Prominence, Convection Zone, Radiation Zone, Core, Photosphere, and Chromosphere

Additional Resources

Do you want to learn more about the cosmos? Take a look at some of these online courses offered by the top institutions from around the world. They can help you get your foot in the door for the subject of astronomy.

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