How old is the Sun?

The Sun is the most visible object in the solar system. It holds 99.8% of the total solar mass and is 109x the size of Earth, and it’s so massive that a million Earth’s could fit in the Sun. 

It is the largest (and only) star in our solar system. However, this still doesn’t tell us exactly how old the Sun is, and how it’s become some big.

How old is the sun?

At 4.6 billion years old, the Sun formed as the result of a nebula so large that it collapsed due to its own gravity. The Sun is the only star of our solar system, and whilst 4.6 billion years may seem old, it’s actually not that old when compared to other stars in our universe. 

Although to us the Sun is old and massive, it’s considered to be a mid-to-low size star when it comes to mass. It will probably take a few billion years for the Sun to evolve into its next stage, when it will evolve into a red giant star.

Then, after a few more billion years, the Sun will eventually evolve into a white dwarf star. According to NASA, it will stay a white dwarf for approximately 10 billion years before slowly progressing into a black dwarf after the Sun releases energy and burns all of its heat.

How do we measure the age of the sun?

There is no way to directly tell exactly how old the Sun is – if you notice, we use like like “approximately” and “around” to give an idea of how old it is based on other stars. 

Because we know the size of the Sun, we know how much energy it emits and we also know about solar wind, we can use all of these smaller details together to get an approximate age.

Then we can cross reference this with other methods like radioactive dating, which tells use how old specific rocks are and when they were last molten – this is from meteorites in the Solar System.

Because they were formed simultaneously with the Sun’s, piecing this data together gives astronomers the ability to determine how old the Sun must be. 

Generally the stars in our universe have a lifetime of 10-ish billion years, though some stars are actually older than this. Considering our solar system is 4.5 billion years old, it’s actually pretty young.


In conclusion, it’s definitely fair to say that the Sun has a relatively short lifespan compared to other stars. The sun is presently a main sequence star, and at 4.5 billion years old, is less than half way through its life cycle.

It will continue to over the coming billions of years – unfortunately, most of us won’t be around to see it!