In basic geography, Earth is popularly known by which colourful nickname because of its appearance when viewed from space?

Introduction / Context:
When astronauts and space probes capture images of Earth from space, our home planet shows a very distinctive appearance dominated by large blue oceans, with white clouds and some brown and green landmasses. Because of this visual impression, Earth has acquired a popular nickname in school geography and general knowledge. This question checks whether you remember that widely used descriptive name.

Given Data / Assumptions:

• We are asked for the popular nickname given to Earth based on its colour as seen from space.
• The options are Orange planet, Green planet, Blue planet and Yellow planet.
• More than 70 percent of Earth surface is covered by water, which strongly influences its colour.

Concept / Approach:
Sunlight reflected from oceans and the atmosphere gives Earth a strong blue tone. School textbooks frequently mention that Earth appears mostly blue from space due to the vast oceans and scattering of light in the atmosphere. Therefore the descriptive nickname used in many competitive exams and general knowledge questions is Blue planet. Other colour names like Red planet are reserved for Mars, not for Earth.

Step-by-Step Solution:
Step 1: Recall that most of Earth surface is covered by oceans, which reflect blue light. Step 2: Remember that photographs of Earth taken from space look mostly blue with white cloud patterns. Step 3: Connect this appearance with common textbook terminology, which calls Earth the Blue planet. Step 4: Compare with other planets: Mars is called the Red planet, while no major planet is commonly called the Orange, Green or Yellow planet in standard school level naming. Step 5: Therefore, select Blue planet as the correct option.

Verification / Alternative check:
If you recall images from famous space missions such as Apollo or modern satellite photos, Earth clearly has a blue dominant colour. Additionally, many environmental campaigns refer to saving the Blue planet, reinforcing this term. Cross checking memory of those references confirms that Blue planet is the accepted nickname in general science and geography exams.

Why Other Options Are Wrong:
Orange planet: No major school level reference describes Earth as the Orange planet. This term does not match the actual appearance of Earth from space.
Green planet: While Earth does have green areas of vegetation, the overall impression from space is not purely green, so this is not the standard nickname.
Yellow planet: This also does not match the usual images of Earth and is not the commonly accepted descriptive name in textbooks.

Common Pitfalls:
Sometimes students confuse nicknames of planets because they try to memorise too many at once. Remember that Blue planet refers to Earth, Red planet refers to Mars and gas giants are usually not given simple colour based nicknames at school level. Linking the nickname to an image in your mind, such as the famous whole Earth photograph, helps you recall the correct term quickly in exams.

Final Answer:
Earth is popularly known as the Blue planet because of its dominant blue appearance from space.