GED Science Question of the Day

1. It will expand into a red giant and then shed its outer layers, leaving a dense white dwarf. (correct answer)
2. It will violently explode in a supernova, leaving behind a black hole.
3. It will collapse directly into a neutron star without any significant expansion phase.
4. It will continue to burn heavier elements indefinitely, becoming progressively brighter.

Explanation: When you encounter questions about stellar evolution, focus on how a star's mass determines its entire life cycle and final fate. Mass is the key factor that drives all stellar processes. For low-to-medium mass stars like our Sun, the evolutionary path follows a predictable sequence. Once hydrogen fusion in the core stops, the star begins fusing helium in its core while hydrogen continues burning in a shell around it. This process causes the star to expand dramatically into a red giant phase. Eventually, after helium is exhausted, the star lacks sufficient mass to fuse heavier elements. The outer layers are gently expelled, forming a beautiful planetary nebula, while the hot, dense core remains as a white dwarf—roughly Earth-sized but incredibly dense. Choice A correctly describes this complete process: red giant expansion followed by the shedding of outer layers, leaving behind a white dwarf remnant. Choice B describes the fate of high-mass stars (over 25 solar masses), which have enough gravitational force to trigger catastrophic core collapse and supernova explosions that can form black holes. Choice C also applies to very massive stars, but neutron stars typically form from stars with 8-25 solar masses—still much more massive than our Sun. Choice D is physically impossible because stars like the Sun simply don't have enough mass to generate the extreme pressures needed for fusing elements heavier than helium. Remember: stellar mass determines stellar fate. Low mass means gentle death (white dwarf), high mass means violent death (supernova, then neutron star or black hole).