Scary news 101: What happens when our sun dies?

Sunday , September 03, 2017 - 12:00 AM

TX. Correspondent

The recent solar eclipse got us thinking more about the sun, but that may have been more of a mistake than you'd think.

Pondering the nature of the cosmos often leads to an existential rabbit hole, and eventually, you get to the big question: What might happen one day when the sun — as is inevitable — begins to die?

Fear not, friends, for I have answers. Here are 10 things to think about in terms of how that catastrophic future event will unfold.

1. The sun will brighten a lot once it exhausts its hydrogen. The brighter the sun gets, the more of its energy the Earth will receive. The gases in our atmosphere — such as carbon dioxide, methane and nitrous oxide — act like a blanket and already hold in heat from the star, allowing the planet to support life. The Earth will become extremely overheated, causing water all over the world to evaporate and create a very dense cloud in the atmosphere. This cloud will protect the Earth’s surface from the sun’s radiation, but after a while, the heat will become too much, the oceans will start boiling, and everything on Earth will be burnt to a crisp.

2. Not only will the sun brighten, but it will also increase in size. Once it uses up all of its fuel, the sun will move on to the next phase in its life cycle: the red giant phase. The actual temperature of the red giant phase is lower than the sun's usual temperature, however — just 2,000 to 3,000 degrees Celsius. That may seem hot, but in comparison to the sun’s regular 5,000 to 9,000 degrees Celsius, it is definitely cooler.

3. The sun will continue to change. Once it's through fusing helium, the sun won't be able to do the same with the remaining carbon, and it will finally shrink from a red giant to a white dwarf. This phase will make the sun much smaller than it currently is. White dwarfs have less energy, but the remnants can continue to shine for billions of years, until they eventually turn into dead black dwarfs. It is impossible to know exactly how long it will be until then, because astronomers currently believe the universe isn't yet old enough to house any black dwarfs!

4. The sun will still hold its center in our solar system. By time the sun turns into a red giant, everything on Earth will obviously be dead, but the planet itself will continue to orbit the star. You'd assume our planet will burn to a crisp, but actually, the opposite will happen. As the sun uses up its energy, its gravitational pull will weaken, and Earth and nearby planets will spiral away from the sun into safer orbits at a further distance (Mercury and Venus, sadly, will not have time to survive with the others).

5. Because of the change in orbits, it may become possible for life to exist on the moons of planets like Jupiter and Saturn. They are both large and have many moons which are already close to being inhabitable — some even have frozen water!

6. Bonus: while the Sun is on its death bed, the Milky Way and Andromeda galaxies, which have been moving toward each other for years, will finally collide and merge with each other. The gases and stars of the two galaxies will fly past each other, creating a spectacular life show that no one on Earth will be able to see (because they're dead). A galactic collision sounds frightening, but really, there's enough empty space inside both galaxies that most solar systems like ours will be fine, just acquire some new neighbors.

7. As for the planets and dwarf planets currently on the edge of our solar system, the sun's enlargement will turn up the heat in the outer region and start to melt the ice on Pluto and other surrounding celestial bodies. It is unlikely that life will form on these dwarf planets, however, because they do not have other conditions necessary, but at least they'll have a little warmth before the sun goes out forever and all of the planets become desolate, frozen rocks surrounded by nothingness.

8. In case it wasn't already clear, life will be absolutely impossible on Earth. The surface and atmosphere will both be too hot for any form of life to ever take hold or flourish ever again. No plants will grow, water will never be cool enough to drink, and survival will become a thing of the past (kind of like Mercury and Venus). If life ever began on another planet or moon, it is highly unlikely that it would look like modern humans, and it would take billions of years before beings as evolved as we are once again populated the solar system.

9. The gravitational pull of Jupiter will throw off the orbits of our solar system's asteroids, because the sun's pull will have decreased so much that the asteroids (like Earth) will fly away from the dying star and be sucked in by the nearest and largest source of gravity. They may even be thrown out of the solar system entirely, if they aren't simply turned to dust due to unexpected collisions.

10. So, is there any hope for the future? It's difficult to predict what kind of technology could exist as the sun moves into the last phases of its life, but it's still fun to imagine the possibilities. We're very close to having the kinds of automatic cars and artificial intelligence that we see in movies, and NASA is already planning missions to Mars for the 2030s. If we found habitable planets before the sun kills us all, we could theoretically use new technology to evacuate the planet and save our species. It's even possible that the ongoing “space race” will have moved outside of the solar system by time the sun starts turning into a red dwarf.

In case any of you are anxious now, the sun won't do anything I've described here for 4-5 billion years. It's much more likely that life on Earth will be taken out by a collision with Mercury or Mars, and even that can't happen for millions, if not billions, of years.

So don't worry — you'll be dead long before humans start to really worry about any of this stuff!

London Cummings is a senior at Fremont High School. She thinks Marvel movies are awesome and wants to travel the world, although she spends most of her time on Tumblr. Email her at

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