@Spacewyrm #63467
More precisely, all stars fuse hydrogen into helium, and as the helium content grows, and pressure increases, it then also begins to fuse helium into lithium, and progressively on to heavier elements. The main reason the much larger stars can keep fusion going up to uranium is because they are so massive, and so energetic, that the heat and pressure is great enough that basically that energy has to go somewhere, even inside the star, and the much more energy intensive bonds to hold larger )and less stable) nuclei together is the only available place for that energy to go. Our sun might make some of the heavier elements, but not as much as the much larger blue stars, because our sun doesn’t have the mass (which also means doesn’t have nearly as much material to work with), and so doesn’t have the energy or potential pressure at its core.
Those much larger and more energetic blue stars though although tend to explode in very impressive supernovas after about 100 million years, whereas our sun is estimated to already be about 5 billion years old, and expected to last another 5 billion or so before the next major change it goes through, which is calculated to be expending enough of the hydrogen that it can no longer maintain normal fusion, the lack of energy production would cause the mass to begin to collapse, until the increased pressure is strong enough to kick up fusion of larger elements again, producing the energy to push the sun’s surface out much farther than now. Probably consuming Earth, and even Mars.