What Would Happen If the Sun Died?

Really, it's the least of our climate-related worries.
15 July 2019, 9:29am
dead sun
Photo: Pexels / CC0

There's a type of humour these days that's often employed to respond to any kind of apocalyptic announcement in the news:

Scientists have warned that the world will be uninhabitable by 2050? That means I don’t have to do my tax return that year... sounds ideal! There's an ever-increasing risk of nuclear annihilation as tensions escalate in a resource-starved world? Well, if we all perish in a terrible war, at least I won’t have to worry about running into my ex!

But for all the undeniable advantages of not being alive, the effects of the sun dying instantly would – unsurprisingly – be: not great. For a start, if the sun's mass suddenly disappeared, Earth would be sent hurtling into space and we'd all be killed immediately. According to all those jokesters longing for death, this would be pretty cool because it'd mean you wouldn't have to worry about how much you're spending on Deliveroo.

How Long Does the Sun Have Left?

An article aimed at "curious kids" – which is pitched slightly above my level of scientific knowledge – informed me that "the sun is currently middle-aged, having celebrated its 4,568,000,000th birthday at some point in the last million years". Which is nice: I like the idea of the fiery monster in the sky that helps to sustain life on Earth getting tanked up on Prosecco with the girls and going to a Take That gig at the MEN arena.

So the good news is that the sun is still likely a good 7 or 8 billion years away from death. And with the way things are going, the chances of humanity lasting that long look pretty slim. Both you and your great-great-great grandchildren can rest easy ⁠– they'll probably die an agonising death in the Water Wars long before then.

But what will happen when the sun does eventually croak? According to an article published by the University of Manchester, it's predicted that it will turn into a planetary nebula; in other words, "a massive ring of luminous, interstellar gas and dust". This is the fate of 90 percent of stars and marks their transition into what is known as a "degenerative white dwarf". Even after the sun has died completely, the heat of its core will be enough to make it shine for a further 10,000 years.

Is There Any Chance It'll Happen Sooner Than That?

Could the sun just randomly go out – like a light bulb – tomorrow? In short: no. It's physically impossible⁠, which makes speculating on what would happen kind of pointless. But let's do it anyway.

It would be grim: basically every plant on Earth would die within a couple of weeks, along with the animals that depend on them for survival, and it would also be quite nippy. But it’s been suggested that humans could survive, for a while, if they lived in submarines in the darkest depths of the Ocean. But that... does not sound like a laugh. You can miss me with that, quite frankly.

If we're talking inevitable death-by-sun, I'd much rather swan around being glamorously depressed like Kirsten Dunst in Melancholia for a week, and then dying instantly in an explosion of fire.