Pioneer probes discovered possible binary companion star. Pioneer 10 and 11 were launched in early 1970s Data showed gravitational anomalies in outer solar system A 'dead star' 4-5 times Earth's size was identified beyond Kuiper Belt

Pioneer 10 and 11 (launched early 1970s) detected gravitational anomalies in the outer solar system. Researchers identify a possible 'dead star' 4-5 times Earth's size beyond the Kuiper Belt, approximately 50 billion miles away. Some theorize this binary companion may explain the Great Year cycle. Note: this remains a theoretical hypothesis, not confirmed.

Key Facts

  • Pioneer 10 and 11 were launched in early 1970s
  • Data showed gravitational anomalies in outer solar system
  • A 'dead star' 4-5 times Earth's size was identified beyond Kuiper Belt
  • Located approximately 50 billion miles away
  • This binary companion may explain the Great Year cycle
  • Kuiper Belt was not discovered until the 1990s