Other Solar Systems We have found >>100 planets around other stars, mainly by radial velocity searches.

• Only gas giant planets close to star!
  
  
• These planets tend to be on very eccentric orbits.

However,

• Radial velocity searches have only found planets around ~10% of stars.
  
  
• They would not have found our solar system.
  • Mercury, Venus, and Earth are way too small.
  • Jupiter's orbital period is too long.
  
  
• So, we have no idea what a typical solar system looks like!

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These discoveries have led to a philosophical change in our thinking.

From: Copernican Cosmological Principle: we are not at a special place.
To: Anthropic Principle: we are at a special place.