Could all the water in the universe put out the sun?
鈥� Fire is a chemical reaction that needs three key ingredients to keeping going: the first is heat (such as from the match used to light a candle), the second is fuel (the candle wax) and the third is oxygen (there鈥檚 plenty of that in the air). Remove any one of those three things and the flame will die. Dousing fire with water is effective because water is very good at removing heat and cutting off oxygen.
However, our sun is not actually made of fire like a giant candle. It is a giant ball of plasma. Rather than combustion, the sun runs on a process called nuclear fusion, where the heat and pressure in the sun鈥檚 core are so vast that small nuclei such as hydrogen are forced to fuse into larger nuclei such as helium, generating blistering amounts of energy and keeping us at a comfortable temperature here on Earth.
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鈥淥ur sun is not made of fire like a giant candle. It is a giant ball of plasma and runs on nuclear fusion鈥�
Enveloping the sun in a thick blanket of water wouldn鈥檛 be much help if you wanted to snuff it out. Although the water would instantaneously remove some heat, it would also increase the sun鈥檚 mass and therefore the pressure inside it, increasing the rate of nuclear fusion. What鈥檚 more, the water molecules (consisting of hydrogen and oxygen) might get hot enough to be ripped apart into their constituent nuclei, providing more fusion fuel. So the sun would actually burn more fiercely and rapidly than before.
But what if you dumped all the water in the entire universe over the sun? Now you鈥檙e talking. Strictly speaking, you鈥檇 be dumping ice rather than water, because space is so cold that almost all water exists in its solid form. You would theoretically be able to add so much to the sun鈥檚 mass in the form of ice that it would use all its fuel very quickly. Then it would explode cataclysmically as a supernova, destroying Earth and leaving behind an extremely dense neutron star, or even a black hole. I guess you could count that as extinguishing the sun. In summary, getting the sun wet is likely to seriously mess up our solar system.
Sam Buckton, Hertfordshire, UK
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This article appeared in print under the headline 鈥淒rowning sun鈥�