Venus
Explanation
The classification of planets in the Solar System often involves comparing their physical characteristics, such as size, mass, and composition, relative to Earth.
Analysis of the Options:
- Venus: It is widely known as "Earth's Twin" because it is very similar to Earth in size, mass, and density. Venus has a diameter only slightly smaller than Earth's (approximately 95% of Earth's diameter) and about 81% of Earth's mass. Both are terrestrial planets with rocky surfaces.
- Mars: Often called the "Red Planet" due to iron oxide on its surface, Mars is significantly smaller than Earth, with only about half of Earth's diameter and roughly 11% of its mass.
- Jupiter: This is the largest planet in the Solar System, a gas giant with a mass more than 300 times that of Earth. It bears no structural resemblance to Earth.
- Saturn: Known for its prominent ring system, Saturn is also a gas giant and is much larger and less dense than Earth.
Key Takeaway: Venus is designated as "Earth's Twin" primarily due to its comparable size, mass, and bulk density, despite having a vastly different atmospheric composition and surface temperature.