The sun is the primary source of energy for life on Earth. It provides heat and light that allows plants to grow and drives Earth’s weather and climate. Without the sun, life as we know it could not exist. But what exactly would happen if the sun suddenly disappeared? How long could life on Earth persist without our nearby star? Here we’ll examine the consequences day-by-day to understand the devastating effects that would occur if the sun vanished.
Day 1 – Temperature Begins to Drop
If the sun disappeared, the first effect on Earth would be a rapid decline in temperature. The sun provides the energy that warms our planet. Without that constant energy input, Earth would quickly start to cool down.
In the first day alone, the average global temperature would drop by around 5 degrees Fahrenheit. Regions in the middle of the day side of the planet would remain warmest, while those on the night side would cool down the fastest.
The cooler temperatures probably wouldn’t be too dangerous for humans and animals initially. But the temperature plunge would just be getting started.
Week 1 – Freezing Temperatures Envelop the Earth
By 1 week after the sun disappeared, average temperatures on Earth would plummet below freezing everywhere. The average high would be about -15°F, with nighttime lows approaching -50°F.
| Time since Sun Disappeared | Average Global Temperature |
|---|---|
| 1 day | 10°C (50°F) cooler |
| 1 week | -15°C (5°F) |
This extreme cold would far exceed anything humans have experienced before. Within a few days, it would become life-threatening to be outside even during the “daytime” without proper protection and heat sources. Food supplies would begin to freeze and become unusable. Most plant life would die off as warmth-loving plants cannot survive hard freezes.
Month 1 – Snow and Glaciation Begin
After about a month without the sun, the world would be completely frozen over. The average global temperature would continue plummeting to around -50°C (-60°F).
With so much moisture still in the atmosphere, heavy snowfall would pile up in formerly temperate regions. Cities like New York, Beijing and London could be buried under meters of snow. Glaciers would start forming and advancing from the poles. The air would also become very dry as moisture in the atmosphere condensed into ice.
Plant and Animal Life
By this point, most plant life would be dead, except for some Hardy trees and shrubs able to withstand freezing temperatures. Animals that could not escape the extreme cold or find protective shelter would begin dying off en masse. Even animals like penguins suited for frigid temperatures would struggle to find food sources as the global food chain collapsed.
Year 1 – The Atmosphere Begins to Freeze
A year after the sun’s disappearance, Earth would be fully encased in ice. The average temperature would now be around -75°C (-100°F), even colder than Antarctica’s coldest recorded temperature.
With such low temperatures, the very air we breathe would start to freeze and fall to the ground. The atmosphere would condense and collapse, eventually concentrating what little warmth remained near the ground. The sky would turn perpetually dark.
Ocean Ice
The oceans would freeze almost completely, potentially over a kilometer deep in some areas. Only pockets of unfrozen sea surrounded by thick ice would remain, thanks to geothermal heat from within the earth allowing minimal circulation.
Survival and Extinction
At this point, the only way to survive on Earth would be underground or in caves warmed by geothermal heat. Some microbes and animals in hydrothermal vent communities on the ocean floor could persist. But all life relying on the sun and photosynthesis would go extinct.
Decades Later – Atmospheric Collapse
Over the course of decades, the atmosphere would continue condensing and falling to the ground. The sky would gradually lower and compress the air into a thin shell hugging the planet’s frozen surface. Breathing near sea level would become difficult without artificial air supplies. Eventually, the atmosphere would disappear.
Centuries Later – Earth Reaches Equilibrium
After a few centuries without sunlight, Earth would reach an equilibrium temperature of around -270°C near absolute zero. At this point, all water would be frozen solid. The air would be almost non-existent. The planet would essentially become a frozen snowball drifting through space.
Life could survive only in small pockets warmed by geothermal heat or in artificially heated environments. Some microbes could persist years longer by metabolizing minerals, but eventually, all life would go extinct without an energy source from the sun.
Conclusion
The complete disappearance of the sun would lead to a swift and devastating collapse of Earth’s climate and ecosystems. Temperature on Earth would plummet rapidly, freezing the surface and atmosphere within 1 year. Over decades to centuries, the atmosphere would condense and disappear, and Earth’s equilibrium temperature would reach near absolute zero.
All life relying on the sun would become extinct. The only survivors would be extremophile microbes in isolated geothermal refuges. A planet that formerly supported a diversity of life would be rendered practically uninhabitable, transformed into a frozen dark sphere drifting silently through space. The sun makes our planet and lives possible. If it disappeared, Earth would be left frigid, dark and ultimately dead.