Given the same mass of fuel, fusion reactions release ... That extra challenge is why it took scientists longer to build a hydrogen bomb than the atomic bomb. Ultimately, to achieve fusion ...

And when you have a large critical mass of uranium-235 or plutonium ... thousands of times more powerful than their atomic predecessors. The first hydrogen bomb the United States ever tested ...

Instead, our Sun will burn through the hydrogen in its core ... creating a nucleus that's one atomic mass unit heavier than before the neutron was absorbed. There are a few nuclei this won ...

The researchers found that the average total mass of atomic hydrogen was comparable to — and possibly larger than — the average mass of stars, providing plenty of fuel for star formation.