UPSC Prelims 2001 Q72: Geography – Astronomy & Earth - Sun System
Who amongst the following was the first to state that the Earth was spherical?
- (a) Aristotle
- (b) Copernicus
- (c) Ptolemy
- (d) Strabo
Answer: (a) Aristotle
Explanation
First to state that the Earth was spherical
| Thinker | Contribution |
|---|---|
| Aristotle (4th century BCE) | Gave proofs that the Earth is a sphere — curved shadow on the Moon in eclipses; stars change with latitude |
| Ptolemy (2nd century CE) | Earth-centred (geocentric) model of the universe |
| Strabo (1st century BCE) | Geographer; wrote the Geographica |
| Copernicus (16th century) | Sun-centred (heliocentric) model |
Among the options, Aristotle is the earliest and the one who argued that the Earth is spherical, using the round shadow of the Earth on the Moon. Pythagoras and Parmenides had suggested it earlier but are not among the options.
Answer: (a) Aristotle.
Why each option is right or wrong
- (a) CORRECT. Aristotle was the earliest of these to argue that the Earth is spherical.
- (b) Incorrect. Copernicus is known for putting the Sun at the centre, much later.
- (c) Incorrect. Ptolemy came later and is known for the geocentric model.
- (d) Incorrect. Strabo was a geographer who came after Aristotle.
Key point
Eratosthenes (c. 240 BCE) measured the Earth's circumference using shadows at Syene and Alexandria.
Remember
Spherical Earth argued by Aristotle; heliocentric model by Copernicus.
Common mistakes
- Choosing Copernicus because of the 'scientific revolution'.
- Mixing a spherical Earth with a Sun-centred universe.
- Ignoring the dates of the four thinkers.
Exam tip
When asked who was first, put the options in date order.
Sources
- Aristotle — On the Heavens (De Caelo), Book II, chapter 14
- NCERT Class XI — Fundamentals of Physical Geography, chapter 'The Origin and Evolution of the Earth'