Overview
This lecture explores Venus, highlighting its similarities and differences with Earth, its extreme atmospheric conditions, and the potential for past or present life.
Physical Characteristics of Venus
- Venus is the second planet from the sun and similar in size to Earth, but slightly smaller.
- Venus has a structure like Earth's: iron core, hot mantle, and rocky crust.
- Its crust features thousands of volcanoes, including Maxwell Montes, nearly as tall as Mount Everest.
Atmosphere and Surface Conditions
- Venus has a thick, layered atmosphere composed mainly of carbon dioxide.
- Clouds in Venus's atmosphere contain sulfuric acid and move at speeds up to 224 miles per hour.
- Surface pressure is similar to being half a mile under Earth's ocean and would crush a human.
- Surface temperatures exceed 880°F, making Venus the hottest planet in the solar system.
- The atmosphere acts as an extreme greenhouse, trapping heat.
Possibility of Water and Life
- Scientists believe Venus may have had Earth-like temperatures and shallow oceans 2.9 billion to 715 million years ago.
- These ancient conditions might have allowed life to exist on Venus.
- Strange dark streaks in the atmosphere, 30 miles up, absorb ultraviolet light and could indicate microbial life.
Observations and Exploration
- Venus reflects 70% of the sunlight it receives, making it the brightest object in the night sky after the moon.
- Over 40 unmanned spacecraft have visited Venus, but its harsh conditions prevent landers from surviving long.
Key Terms & Definitions
- Greenhouse gases — gases like carbon dioxide that trap heat in a planet’s atmosphere.
- Surface pressure — the force exerted by the atmosphere at a planet’s surface.
- Sulfuric acid — a highly corrosive acid found in Venus’s clouds.
- Maxwell Montes — the tallest volcano on Venus.
Action Items / Next Steps
- Review the similarities and differences between Venus and Earth.
- Read about Venus exploration missions and recent atmospheric research.