Why in the News?

This newscard is an excerpt from the original article published in The Hindu.

What is the Rare Earth Hypothesis?

About: Proposed by Peter Ward (palaeontologist) and Donald Brownlee (astronomer) in 2000, it suggests that simple life (like microbes) may be common, but complex life (like plants and animals) is extremely rare in the universe.
Core Idea: Earth supports advanced life because of a unique mix of conditions such as a stable orbit, a protective magnetic field, active plate tectonics, and giant planets like Jupiter that shield it from asteroids.
Meaning: The Earth is not an ordinary planet; it is a special case where everything aligned perfectly to allow complex life to evolve.

Drake Equation / Mediocrity Principle: Say that life should be common since there are billions of stars; the Rare Earth Hypothesis says complex life is rare even if basic life is not.
Fermi Paradox: Asks “Where is everybody?” The Rare Earth answer is that complex intelligent life is rare, so we don’t see others.
Copernican Principle: Claims Earth is ordinary; the Rare Earth Hypothesis argues Earth is extraordinary and rare in its conditions.

Exoplanet Studies (Kepler Mission): Thousands of Earth-sized planets found, but few have stable climates or protective atmospheres like Earth.
M-dwarf Planets: Many orbit small stars and lose their atmospheres due to strong radiation.
No Alien Signals: Breakthrough Listen and other searches found no technosignatures from intelligent civilizations.
Earth’s Uniqueness: Plate tectonics and a carbon cycle help Earth keep a stable climate for billions of years; such conditions have not yet been found elsewhere.

Current View: Microbial life might exist on many planets, but stable, complex ecosystems like Earth’s are probably rare.
Ongoing Studies:
- James Webb Space Telescope (JWST) searches for gases like oxygen, methane, and water on distant planets.
- Planetary models test if other worlds have tectonics or internal heat for climate balance.
- Technosignature surveys continue for traces of intelligent life.
Future Missions: Extremely Large Telescope (ELT) and Habitable Worlds Observatory (HWO) will study exoplanet atmospheres more closely.
Significance: The Rare Earth Hypothesis remains plausible but unproven, showing that life may be widespread, but Earth-like complexity could be one of the universe’s rarest achievements.

[UPSC 2018] Which of the following phenomena might have influenced the evolution of organisms?

1. Continental drift

2. Glacial cycles

Select the correct answer using the code given below.

Options: (a) 1 only (b) 2 only (c) Both 1 and 2* (d) Neither 1 nor 2