We use water to put fires out because they can‘t burn through the coating of water over their fuel. But there’s no air in space, and water can‘t stop the thermonuclear reactions that cause the sun to burn. Our huge glass of water would actually make the sun get hotter and burn 6 times brighter.
Then, can you put the sun out with water?
You can not put out the Sun with water. Indeed, water would fuel the nuclear fusion processes that make the Sun “burn”. It would not only not be extinguished, it would end up getting hotter. At best, you could use a couple hundred billion times as much water as we have on Earth to basically destroy the Sun.
One may also ask, how large would a bucket of water have to be to put out the sun? Sun’s overall density is 1.4 times that of water. So if you have a bucket of water equal to the volume of the Sun, that water will have 1/1.4 = 0.71 times the mass of the sun, or 0.71 solar masses.
Just so, what would happen if you went near the sun?
Well first thing’s first: You would disintegrate. At the temperature of the Sun, most of the molecules that make up our bodies could not even survive, that is why we would not only fry and die, we would really disintegrate (all the molecules breaking apart, leaving only loose atoms).
What would happen if we put water on the Moon?
Liquid water cannot persist at the Moon’s surface, and water vapor is decomposed by sunlight, with hydrogen quickly lost to outer space. However, scientists have conjectured since the 1960s that water ice could survive in cold, permanently shadowed craters at the Moon’s poles.