Video: Understanding Nuclear Fusion in Stars

Which element do main sequence stars primarily use for nuclear fusion?

01:17

Video Transcript

Which element the main sequence stars primarily use for nuclear fusion?

Okay, so, to answer this question, let’s first recall that the main sequence is literally the main phase of a star’s life. If this is our star, slightly egg-shaped for some reason, then the main sequence is set to begin when in the core of the star, the temperatures and pressures are high enough for nuclear fusion to begin. But the fact is that this star was formed due to the gravitational collapse of clouds made up of mainly hydrogen gas.

Now, hydrogen is the most abundant element in the universe. It is also the lightest possible element in the universe because it literally just needs one proton in its nucleus. And it may or may not have some neutrons. But even if it was just one proton that would classify as hydrogen. So, it seems highly likely, then, that what’s fusing in the core of the star is hydrogen because the star is mainly made of hydrogen.

But the other important thing is that nuclear fusion is a process that releases energy. In other words, nuclear fusion is the energy source of our star. And when nuclear fusion is happening, as a general rule, the lighter the element being fused, the more energy is released by this process. And since hydrogen is the lightest possible element in our universe, as well as what these stars are made up of, that points us very strongly in the direction of hydrogen being the element that main sequence stars primarily use for nuclear fusion.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.