Final answer:
The purpose of comparing an explosion to the energy of a modern nuclear bomb is to help readers gauge the significant power of the explosion. This analogy provides a familiar context for understanding the magnitude of events like meteor impacts, which can release immense energy and cause substantial effects even without creating a crater.
Step-by-step explanation:
The comparison stating that an explosion released as much energy as a modern nuclear bomb serves the purpose of helping readers understand how powerful the explosion was (option c). Such comparisons are often used when describing events such as meteor impacts because they give readers a reference point that is widely recognized. The usage of a nuclear bomb as a comparison does not suggest that meteors can be a new source of energy (option a), describe the damage in Russia (option b), or demonstrate that nature is stronger than humans (option d) directly. However, mentioning the energy equivalence to a nuclear bomb indirectly conveys the potential for destruction and compares a natural event with a well-known man-made explosion.
Atmospheric explosions, like the Tunguska event in 1908 and the Chelyabinsk incident in 2013, showcase the immense energy released upon a meteor entering the Earth's atmosphere and exploding. Even without a crater, the Tunguska event flattened an area of forest the size of a major city, akin to the devastation that could be wrought by the most powerful of today's nuclear weapons. The Chelyabinsk asteroid, although smaller in size, still caused significant disruption by releasing an energy burst of 500 kilotons and injuring approximately 1500 people due to shattered glass from blown-out windows.