Final answer:
The central idea of the text is that supernovae represent the death of massive stars, playing a critical role in the evolution of galaxies by releasing heavy elements necessary for the creation of new stars, planets, and life, as well as providing valuable information to scientists about the universe.
Step-by-step explanation:
The central idea of the text is that supernovae are remarkable celestial events that signify the death of massive stars and have significant importance in the history and evolution of the galaxy. As stars approach the end of their lifespan, they often explode in supernovae, which eject newly formed elements into interstellar space. These elements are crucial for the formation of new stars, planets, and potentially life, making supernovae essential in the cosmic cycle of matter and energy.
Furthermore, these explosions not only enrich the surrounding medium with heavier elements but also teach scientists about the universe. Studies of events like SN 1987A have allowed us to confirm theoretical models of supernovae and their aftermaths, such as the creation of neutron stars and the dispersal of elements necessary for life as we know it.
From the provided text, we can infer that option D: Supernovae are star explosions that teach scientists about the universe, aligns closest with the central idea described.