How Much Longer Until The Sun Dies?

The sun has been an object of worship and fascination for tens of thousands of years, and there is some wisdom to this, as without it life simply could not exist.

The sun is what gives our planet the temperatures and light we need to sustain the plants and other important creatures that make up all of nature.

But is the sun always going to stay the same? Will it remain a stable provider of energy, light, and heat forever and what can we do if that isn’t the case?

Studies into the nature of our most important celestial body have been going on for some time now, and while our knowledge of the sun has been limited by our tools and understanding, recent decades have seen a huge leap forward in our understanding of stars, including the sun, their life cycles, and what this means for us.

In this guide, we’re going to answer these questions and more, because there’s nothing like a little existential dread and fear to bolster your faith in life and develop a deep and lasting fear and reverence for the universe and our imperceptibly minor place within it.

But let’s start with something a little more simple and relatable.

How much longer is it until the sun dies? And will it die at all?

The sun is an almost perfect sphere of hot plasma, maintained by the intense heat and forces of nuclear fusion reactions which occur at the core of the celestial body, and which cause the light, heat, UV light, and radiation that the sun emits and which provides us and all Earth's species with the energy to sustain life.

Without this energy, the Earth would be a dark world devoid of even basic life, more akin to something like the moon perhaps, or maybe mars or venus. A blasted rock like so many other planets in the universe.

There are many types of stars and they are categorized into various groups to make studying them and monitoring them easier.

The Sun is known as a G-type Main sequence star and is informally known as a yellow dwarf. Yes, despite its incredible size and energy, the Sun is really an incredibly small star compared to some other types.

Scientists believe the Sun was formed some 4.6 billion years ago when there was a gravitational collapse that occurred within a large molecular cloud or stellar nursery.

It is believed that the sun will reach the end of its life cycle in around 10 billion years, however, any remnants of humans, or indeed Earth by that point in time will not be around to witness this due to an array of factors which we’ll explain in the next sections.

Is The Sun Getting Hotter?

In short, yes, the sun is becoming hotter as time goes by, and scientists estimate that the luminosity of the Sun will increase by a factor of around 6% for every billion years that passes.

Now, this may not sound like much, and a billion years is an incredibly long time, so 6 percent spread over such a period is surely minuscule right?

Wrong. The bad news for Earth and those of us still lucky (or perhaps unlucky) enough to still be here by that point is that the increased heat and size of the sun by this point will render Earth utterly uninhabitable and inhospitable for almost all life in just 1.1 billion years, which again sounds like a long time but in stellar and cosmological terms it isn’t very long at all.

The planet by this point will be too hot to support life, and things will only get worse as time goes by. Scientists believe that the sun will continue to heat and expand as it enters maturity. In its latter stages of life, things get even crazier, but we’ll touch on this in the next section.

We had better get our skates on and start considering some new real estate, as eventually, Earth is going to get rid of us whether we like it or not!

Is The Sun Getting Weaker?

At a certain point in time, long after the sun has cooked Earth and anything unfortunate enough to still be living on it, the sun will eventually start to cool down, but by this point, much of the solar system will have likely changed due to the sun’s increased heat and size.

Indeed at a certain point, the sun will expand exponentially when its hydrogen fusion in its core ceases, and its hydrostatic equilibrium becomes unbalanced.

The sun will turn into a red giant and will have become big enough to totally swallow Mercury and Venus, rendering Earth comparable to these two heat-blasted and irradiated planets.

This won’t happen for some 5 billion years, so we still have some time to consider changing neighborhoods, but to survive humanity will need to seek a new star and become an interstellar species, and as of right now this seems to be a very remote possibility due to technological as well as political limitations.

Eventually, the sun will progress from a red giant as its outer layers are shed and it condenses into a small white dwarf star that is generally much cooler; however, there will be periodic bursts of energy and light as the star becomes increasingly unstable. It will not produce any energy by fusion any longer, but will still glow and give off some heat due to the sheer heat and power of its previous life cycles.

It is hypothesized that the white dwarf will eventually turn into a black dwarf after trillions of years when the temperatures become low enough and almost all the processes of the star cease as we understand them.

What Kind Of Star Is The Sun?

It is a G-type Main Sequence star, and although small compared to many other types of stars in the universe it still contains over 90% of all the mass in the solar system and is by far the biggest object within it.

Our galaxy, the milky way, is mostly made up of red dwarf stars.

Eventually, our sun will change as it progresses through the various stages of its stellar life and will progress first to a red giant, then a white dwarf, and then finally a merely theoretical black dwarf.

What Will Happen When The Sun Dies?

When the sun dies the solar system as we know it will be almost unrecognizable. Mercury and Venus will have been swallowed up long before the sun dies in the period where it grows to a red giant.

Earth will be a nearly unrecognizable rock similar to Mercury and Venus today, while many of the other planets and bodies will have undoubtedly been affected by the vast changes the sun will go through.

Eventually, the sun will shrink and cool to a white dwarf, and while it will be slightly smaller than it is today and give off slightly less heat, the period of its red giant phase will have scoured most of the solar system of life leaving almost nothing unaffected.

It is theorized that as the sun cools it may become a planetary nebula, and eventually a black dwarf; however these are theories that are not yet proven and are subject to ongoing study and debate.

Can We Stop The Sun From Dying?

In a word, no. Humans lack the ability to prevent these processes, as they are far too vast and forceful to be meaningfully impacted by anything humans could hope to muster.

The only means humans have of surviving the changes the sun will go through will be to seek to colonize another solar system and become an interstellar species, however, this presents many of its own unique and immense challenges, and right now humanity seems to lack many answers to the logistical and technological problems presented by this potential reality.

Gordon Watts
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