Re: “It then mixes with hydrogen in clouds of dust and gas out in space and forms water.”
There needs to be an energy source for fusion.
I can’t figure out where the energy comes from.
From inside the planets when they form?
From super heated gases caused by star death?
Water is a molecule, made by chemistry, not the product of nuclear fusion.
H + H + O is exothermic, so if you have hydrogen and oxygen just hanging out around each other they with tend to combine, sometimes with great vigor :)
No, there doesn't, because it isn't fusion, it's bonding. Chemical bonding in nature occurs from the energy the atoms carry within themselves. No batteries required.
Excerpt from this article.
Water is crucial for life, but how do you make water? Cooking up some H2O takes more than mixing hydrogen and oxygen. It requires the special conditions found deep within frigid molecular clouds, where dust shields against destructive ultraviolet light and aids chemical reactions. NASA’s James Webb Space Telescope will peer into these cosmic reservoirs to gain new insights into the origin and evolution of water and other key building blocks for habitable planets.Manly Warrior: About space being pretty much empty of gaseous matter... No! It's full of HUGE clouds of gas and dust (sometimes called stellar nurseries) that measure tens of light years across. Look up at the Milky Way some night and you'll see dark splotches blocking out much of the light from the more distant stars in the galaxy. Those splotches are clouds of gas and dust, and all the stars in the galaxy were born in them.A molecular cloud is an interstellar cloud of dust, gas, and a variety of molecules ranging from molecular hydrogen (H2) to complex, carbon-containing organics. Molecular clouds hold most of the water in the universe, and serve as nurseries for newborn stars and their planets.
Protoplanetary disk surrounding a young star In this animation we fly into a protoplanetary disk surrounding a young star. Within the disk, tiny dust grains accumulate layers of ice over thousands of years. These cosmic snowflakes are swept up by forming planets, delivering key ingredients for life. Credits: NASA/JPL-Caltech/R. Hurt
Within these clouds, on the surfaces of tiny dust grains, hydrogen atoms link with oxygen to form water. Carbon joins with hydrogen to make methane. Nitrogen bonds with hydrogen to create ammonia. All of these molecules stick to the surface of dust specks, accumulating icy layers over millions of years. The result is a vast collection of “snowflakes” that are swept up by infant planets, delivering materials needed for life as we know it. "If we can understand the chemical complexity of these ices in the molecular cloud, and how they evolve during the formation of a star and its planets, then we can assess whether the building blocks of life should exist in every star system," said Melissa McClure of the Universiteit van Amsterdam, the principal investigator on a research project to investigate cosmic ices.