Could We Survive Losing The Sun? Unveiled

Could We Survive Losing The Sun? Unveiled

VOICE OVER: Callum Janes
What would happen if the sun disappeared?? Join us... to find out!

In this video, Unveiled takes a closer look at what's arguably the worst and most extreme "what if" scenario for the entire solar system: What if we lost the sun? Could we survive? How would the rest of space adapt? And do we already have plans in place that could help us carry on?

Could We Survive Losing the Sun?

The sun is the single most important ingredient for life on Earth. Without it, our atmosphere would struggle to form, all our water would freeze, and we’d be too cold to survive. But what if we couldn’t rely on this billions-year-old heat source anymore?

This is Unveiled, and today we’re answering the extraordinary question: could we survive losing the sun?

It’s inevitable that one day, we WILL lose the sun. The sun, like all stars, has a finite lifespan, and eventually it will run out of hydrogen. When this happens, it will become a red giant, expanding rapidly and creating an outer “envelope”. This envelope will engulf all the inner planets and make the outer planets and their moons far warmer, but it won’t last. Eventually, the envelope will be gone too, and we’ll be left with nothing more than a white dwarf. White dwarfs are the dead cores of stars and they’re extremely long-lived. Despite the fact they aren’t fusing hydrogen anymore, they still radiate a lot of heat. It’s thought that eventually, white dwarfs will fade into black dwarfs, but that the universe is too young for any black dwarfs to actually exist yet. When the sun dies in about five billion years, if humans are still around, we’ll have to learn to get along with a significantly reduced heat source. First though, we’d need to leave Earth and go to one of the outer moons like Titan or Europa, otherwise we’d be burned up. We would still have a star at the center of the solar system, though, and it would still produce enough heat to keep us going for billions of years – even if we have to orbit it in a spaceship.

But what if the sun were to spontaneously vanish in the blink of an eye?

First of all, we wouldn’t notice that this had happened for around eight minutes. It takes this long for light to travel from the sun to Earth, so we’d have more daylight left than Mercury or Venus, but not as much as Jupiter. Even Pluto is only six light-hours away at most – though, this is still a lot better than eight minutes. We would not instantly freeze, however. There would be some residual heat from the sun that would linger, potentially for a few weeks. In addition, heat also flows from the Earth’s interior to the surface from two main sources. The first is primordial heat from the Earth’s core that’s leftover from the planet’s formation. The second is radiogenic heat, produced by radioactive decay in the mantle and crust. However, the amount of heat that flows to the surface is nothing compared to the warmth of the sun. It’s only about 1/10,000th of the heat the sun provides, so we’re still going to be in dire straits.

Once those first eight minutes were up, we would be plunged into darkness. It’s sunlight reflecting from the other bodies in the solar system that make them visible to us here, so we’d also no longer see the moon. The moon would still be there, but it would produce no moonlight, leaving us in pitch darkness with no sense of day or night. Eventually, we’d also lose sight of all the other planets, though we would still be able to see other stars distantly in the sky. They’re nowhere near close enough to provide us with any heat, however. Estimates differ, but within a few days, the average global surface temperature would drop to at least 0 degrees Fahrenheit - leaving much of the world uninhabitable. Sure, you could rug up at home, but that would only help for a short time, because temperatures would continue to plummet. Eventually, they’d reach about -400 degrees Fahrenheit. This is close to absolute zero, or zero kelvin, which is equivalent to -459.67 degrees Fahrenheit. Absolute zero is the temperature at which atoms stop moving. Even with the loss of the sun, Earth will never quite reach absolute zero, due to those other heat sources. But it would still leave us very little chance of survival. Even the atmosphere would freeze, leaving us struggling to breathe. And with time, all the liquid water on the planet’s surface would completely freeze as well.

But it is possible to withstand exceptionally cold temperatures. The International Space Station, while still comparably a lot warmer than absolute zero, gets as cold as -250 degrees Fahrenheit on the side facing away from the sun. Though the hot side reaches 250 degrees above zero, engineers say that keeping the ISS warm is a lot harder than keeping it cool. But we’ve still managed to pull this off. It’s really just a question of insulation and having a big enough power source to keep creating heat. If the sun went out, the best fuel source would arguably be nuclear. Our attempts at harnessing nuclear fusion, the same process that powers the sun, still have a long way to go. But nuclear fission generators are abundant. Nuclear reactors only need refueling every two years, sometimes a little more frequently. We wouldn’t have time to build new nuclear infrastructure, so the people in the best position to survive this cataclysm would be the ones who are working in nuclear plants. Those skilled workers will be needed to keep the plant running and they’ll be the closest, so if you’re a nuclear engineer then you have a good chance at surviving longer than other people. However, you’d still need a food and water supply.

It just wouldn’t be possible to develop this infrastructure without warning. However, if we did somehow have warning that the sun was going to vanish, we’d need to build some habitats. These habitats would essentially be the same as those we’d need to build if we were going to live on Mars. Mars’ surface temperature gets extraordinarily cold, as cold as -220 degrees during the Martian winter, and we’re already developing the technology needed to withstand this. We would need an enclosed, artificial environment where we can generate our own heat using nuclear power, grow plants and food, and keep a constant cycle of fresh water and air. Luckily, our water wouldn’t disappear, it would only freeze, so we could get water by sending people out to gather ice. These people would need some very high-tech suits, essentially spacesuits, to do so, but it would be possible. Alternatively, we could build robots that could do it for us. After all, many robots have been sent to Mars that survive not only the temperatures but the radiation on the Red Planet, and without the sun there would be far less radiation to contend with. And there’s the added bonus that we wouldn’t be launching these robots into space, so developing them would be far easier.

Another solution would be to build a generation ship. It would also be an artificial habitat, but we wouldn’t be attached to a planet at all, we’d be free to fly through space and potentially seek out a new home world. This would be much harder than building habitats on Earth though, and it would mean abandoning the small amount of heat that Earth would still provide. However, if the sun went out, we might have a very good reason to want to leave Earth as quickly as possible.

The sun doesn’t just provide us with heat, it’s also the center of our world – literally. Without the sun to keep the solar system together and perfectly balanced, chaos would eventually reign. The best-case scenario is that the solar system would reorganize itself around the second most massive object, Jupiter. But this would bring problems of its own. With all the planets hurtling towards a new point of gravity, there would be the potential for a planetary collision, and wouldn’t be something we could predict. At least if we were piloting a generation ship, we’d be able to fly in the opposite direction, away from the planets. Another scenario however is that the Earth would just be cast adrift as a rogue planet. Rogue planets are lonely celestial bodies that orbit the galactic center instead of a parent star, meaning they spend their entire lives in the freezing darkness of deep space.

As a rogue planet, Earth could get pulled in by another star, but it doesn’t seem likely that it would end up in the perfect, habitable zone for a second time. It’s already so unlikely that Earth exists at all, let alone existing twice. But staying on it would mean we’d at least have a natural heat source, no matter how small.

A few people would live if they happened to be in exactly the right place at the right time, and with enough preparation perhaps millions could adapt to this eternal winter. And that’s whether we could survive losing the sun.