Comets only glow in a certain region of their orbits. This happens because _______ .

Options

A. unlike other celestial objects, their orbits are circular in shape
B. those specific regions of their orbits pass through the sun
C. those specific regions of their orbits contain ice and dust particles
D. one part of their orbits is closer to the sun than the other

Answer

**Step-by-Step Solution:**

1. **Understanding Comet Orbits**: Comets travel in elliptical orbits around the Sun. This means that their distance from the Sun varies as they move along their path.

2. **Proximity to the Sun**: When a comet is near the Sun, it experiences increased solar energy. This energy causes the comet's ices to sublimate (turn from solid to gas) and release gas and dust, creating a glowing coma and tail.

3. **Energy Loss When Far Away**: As the comet moves away from the Sun, it loses energy. The sublimation process slows down, and the comet's glow diminishes significantly.

4. **Conclusion**: Therefore, comets only glow in certain regions of their orbits, specifically when they are close to the Sun where they can absorb enough energy to produce the glowing effect.

**Final Answer**: Comets only glow in a certain region of their orbits because they receive more energy from the Sun when they are closer to it.

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