The sun must be stopped - with seawater!

[Dag_Otto]

@Autolycus

Let us assume for the sake of argument that there is an infinite supply of seawater.

Then the answer is easy: All of it.

[Chessic_Sense]

@Chronos

Quoth AndrewL:You certainly could. When the Sun eventually dies a natural death, it’ll still have about 90% of its original hydrogen remaining. The dying is triggered by having too much waste helium, not by having not enough hydrogen. And anything more massive than helium will work even better. My guess is that by adding water to the Sun, you’re doing more to quench it with the oxygen than you are to fuel it with the hydrogen.

And it’s seawater at that. So there are heavier elements there, too.

[DHMO]

@Chronos

You certainly could. When the Sun eventually dies a natural death, it’ll still have about 90% of its original hydrogen remaining. The dying is triggered by having too much waste helium, not by having not enough hydrogen. And anything more massive than helium will work even better. My guess is that by adding water to the Sun, you’re doing more to quench it with the oxygen than you are to fuel it with the hydrogen.

It would be hard (or impossible) to “quench” the solar furnace with Oxygen, since Oxygen is one of the steps in the CNO cycle of stellar fusion, and acts as a catalyst to the fusion reaction.

The basic equation is: four Hydrogen atoms fuse to form one Helium nucleus, with the concomittant release of enormous energy. In stars of approximately the mass of our Sun, the proton-proton reaction predominates. At a mass of about 1.3 Solar masses or more, the CNO cycle is dominant. If you add enough water to theoretically “quench” the fusion reaction at the Sun’s core, you have added a sufficient amount of matter to easily increase the Sun’s mass to the tipping point where CNO predominates, mostly by adding a lot of Hydrogen fuel, and enough extra Oxygen to speed the reaction.

This will quench the Solar furnace about as well as throwing gasoline on a burning house.

[Dag_Otto]

OK, then. None of it.

[Canadjun]

@Chessic_Sense

But the water would displace the hydrogen and helium at the core. If you used iron, wouldn’t the iron sink to the center of the star and stop fusion at some point before the star would be so massive that it could fuse iron?

Wouldn’t the hydrogen float on top of the iron and continue fusing?

[Fear_Itself]

@Canadjun

Wouldn’t the hydrogen float on top of the iron and continue fusing?

At those temperatures, iron would be an incandescent plasma.