43. Why do comets develop tails when they are near the Sun?
Answer: C
Comets develop tails due to the evaporation of ice and the release of dust particles.
As comets approach the Sun, the heat causes the ice within them to evaporate, creating a cloud of gas and dust that forms a tail. This tail is primarily composed of these released particles, which are pushed away from the Sun by solar wind and radiation pressure.
A) The increasing rate of debris impacts as the comet approaches the Sun
This option is incorrect because the formation of a comet's tail is not caused by debris impacts. While comets may encounter debris in space, the tail is formed primarily through the sublimation of ice and the ejection of gas and dust, not from collisions.
B) The increasing velocity as the comet approaches the Sun
While a comet does gain velocity as it gets closer to the Sun due to gravitational forces, this increase in speed does not directly cause the formation of a tail. The tail results from the physical and chemical processes occurring within the comet as it heats up, rather than the speed itself.
C) The evaporation of ice and the release of dust particles
This option is correct because, as comets near the Sun, the heat leads to the sublimation of ice, which releases gas and dust particles. This process creates a glowing coma and a tail that points away from the Sun, driven by solar radiation and wind.
D) The combustion of flammable compounds in its atmosphere
This option is incorrect since comets do not combust in the traditional sense. The materials in a comet primarily consist of ice, dust, and rocky materials, which do not burn but rather sublimate when heated by the Sun, leading to tail formation without combustion.
Conclusion
The correct answer, C, accurately describes the scientific process behind the formation of a comet's tail, which is driven by the evaporation of ice and the release of gas and dust particles as the comet approaches the Sun. All other options fail to explain this phenomenon accurately, focusing instead on irrelevant factors such as impacts, velocity, or combustion.