What would happen to Earth if the sun suddenly vanished?
The sun has been Earth’s constant companion since the emergence of our planet. But if the sun suddenly disappeared, what would happen to our home planet?
To understand the fate of a sunless Earth, it is important to know how both came to be. THE sun formed about 4.6 billion years ago, when a massive cloud of rotating gas and dust collapsed on itself and condensed, creating the largest object in what would become our solar system and eventually reaching a temperature of 27 million degrees Fahrenheit (15 million degrees Celsius) at its core.
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If the sun suddenly disappeared, Earth and the vast majority of life would be in dire straits. This would set off “a time bomb on the survival of every living thing on Earth that depends on photosynthesis, which represents the vast majority of life on the surface and all of humanity,” Timothy Croninassociate professor of atmospheric sciences at MIT, told Live Science via email.
For at least 8 minutes and 20 seconds, no one would know that the sun had disappeared – that’s how long does it take for sunlight to reach earth. During that time, “we would almost certainly have no idea what had happened,” Cronin said.
That’s when the real trouble would begin.
After the sun’s eight-minute swan song, there would be “a sudden power outage,” Cronin said. Without sunlight, artificial lighting from electricity, oil, or gas would be the primary means by which we could still produce light, as well as fire, bioluminescence and fluorescence. We would lose the notion of day and night. The moon, which reflects sunlight, would become completely dark, although distant stars in the sky would still be visible. And without the mass of the sun and gravity By keeping the planets and other celestial bodies in orbit, “all the planets would fly off in the direction they’re currently moving,” Cronin said.
But humanity would have more immediate problems than blasting off into interstellar space. The absence of sunlight would mean that crucial processes, such as growing food, would become much more complicated.
Photosynthetic organisms would be finished, Michael Summersprofessor of planetary science and astronomy at George Mason University in Virginia, told Live Science. Most plants that were not grown under artificial lighting would quickly suffer. And although some “may remain dormant for weeks or even months, as is the case in winter, all photosynthetic organisms will eventually die.”
Fungi, on the other hand, feed on living or dead matter, and “there would be a large amount of dead matter available,” Summers said. So the mushrooms would probably die not from lack of food, but from the cold.
cold planet
It won’t take long for freezing temperatures to change Earth as we know it.
Early on, the Earth cooled on average by about 36 F (20 C) every 24 hours, Summers said. “This almost plunges the entire world into subzero temperatures in just two to three days,” although as it gets colder, the daily temperature change will decrease, he said. Small ponds can freeze over within a week, while lakes can take weeks or even months. The oceans could persist “for many years, even decades,” and in some places, like “the deepest parts of the oceans where volcanoes are found, they could remain liquid potentially for as long as the volcanoes last,” Summers said. “And that could take billions of years.”
To understand how cold the Earth would eventually become, consider Pluto. Right now, Pluto is “about 40 times farther from the sun than Earth, and the temperature there is currently about minus 400 degrees Fahrenheit.” [minus 240 C]”, Summers said. “Once you eject Earth from our solar system, it will move away from Pluto very quickly.”
But the Earth’s temperature would not reach absolute zerothanks to the Big Bang this happened about 13.8 billion years ago. Even “the lowest temperatures in the universe are limited by the heat left behind by the Big Bang,” Summers said. “Take any object very far from a star and let it cool for a million years,” and it will still be a few degrees above absolute zero. The temperature of the residual radiation known as cosmic microwave background is approximately minus 454 F (minus 270°C), while absolute zero is slightly colder at around minus 459 F (minus 273 C).
At ultracold temperatures, human civilization and most life would almost certainly collapse. “It’s conceivable that people could survive underground in caves, using geothermal or nuclear power, with plants grown under artificial lighting,” Cronin said, “but that would be a problem.” extinction event to make everyone else look puny. »
What would survive?
One thing that could survive? Near-microscopic animals called tardigradesalso known as water bear. “Ugly little creatures,” Summers said, but “hard to kill.” They can be zapped by radiation or submerged in certain types of alcohol and still survive; Maybe hitting them with a hammer would kill them, he suggested. “Otherwise, they are one of the most resilient life forms on Earth.”
Likewise, bacteria that do not require photosynthesis, like the types that live around deep ocean ventswould probably survive. Indeed, certain microbes, notably certain bacteria and archaea, use chemosynthesisas opposed to photosynthesis, to “live off the chemical bonds of rocks and minerals,” Summers added.
Fortunately for humanity, there is no reason to believe that the sun will disappear in the blink of an eye. But over time, the sun will disappear. It will continue to create heat and light for another approximately 5 billion yearsbut once its fuel is exhausted, it will expand into a red giant, engulfing Mercury and Venus and perhaps Earth. Either way, humans probably won’t last that long; the gradual increase in the luminosity of the sun is expected to vaporize Earth’s oceans in a little over a billion years.
Even though these impacts might be far away, Summers said it’s important to consider the potential outcomes. When “we better understand stars and how they can change over time, on short and long time scales, we better understand the universe.”
Soleil Quiz: How well do you know our local star?
