21. Accurate measurements, beginning in the early 1970s, have detected nucleosynthesis in supernovae. 22. :: Have a look at stellar nucleosynthesis . 23. This evidence bolstered the hypothesis that heavier elements are the product of nucleosynthesis in stars. 24. :Theoretically all heavy elements are derived from lighter elements ( see Supernova nucleosynthesis ). 25. Planetary nebulae play a crucial role in the heavy elements and other products of nucleosynthesis . 26. In 1967, Bethe was awarded the Nobel Prize for this work on stellar nucleosynthesis . 27. Citations are in the Nucleosynthesis section below. 28. Asked how long the entire process of primordial nucleosynthesis had taken, Alpher answers 300 seconds. 29. Calcium is produced in supernova nucleosynthesis . 30. The most important fusion process in nature is the one that powers stars, stellar nucleosynthesis .
