To an astronaut in a space-ship, the earth appears :

Options

A. A) white
B. B) red
C. C) blue
D. D) black

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the color of Earth as perceived by an astronaut in a spaceship. We need to determine which color the Earth appears to be from that perspective.

2. **Considering the Options**: The options provided typically include colors such as blue, green, white, and brown. We need to analyze which of these colors is most likely to be observed from space.

3. **Knowledge of Light Scattering**: It is important to recall the concept of Rayleigh scattering, which explains why the sky appears blue. When sunlight enters the Earth's atmosphere, it interacts with air molecules and scatters in all directions. Blue light is scattered more than other colors because it travels in shorter, smaller waves.

4. **Observation from Space**: An astronaut in a spaceship is above the atmosphere, but the light scattering still affects how the Earth looks. The vast oceans covering about 70% of the Earth's surface reflect blue light, and the atmosphere contributes to this blue appearance.

5. **Conclusion**: Based on the scattering of sunlight and the reflection from the Earth's oceans, it can be concluded that the Earth appears predominantly blue to an astronaut in space.

6. **Final Answer**: Therefore, the correct answer is that to an astronaut in a spaceship, the Earth appears **blue**.

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