Sun, planets, asteroids, moons, and comets {solar system}| formed 4,600,000,000 years ago. Solar system has 10^13 meter diameter, has mass 10^36 grams, and will last 10^16 seconds.
space between planets
Space between planets has 10 ions per cubic centimeter.
space erosion
Space objects erode by 0.001 meters every 10^6 years.
Pioneer spacecraft
Pioneer 10 and Pioneer 11 spacecraft photographed Jupiter and Saturn [1972 to 1973] and are now outside solar system. At 10 astronomical units, they slowed from projected speed {Pioneer anomaly}. Researchers do not yet know slowdown direction. If it is toward Sun, it indicates something new about gravity. If it is toward Earth, it indicates something about light velocity. If it is along motion direction, it indicates something about inertia or drag. If it is along spin axis, it indicates something about Pioneer spacecraft.
Physical Sciences>Astronomy>Solar System
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Date Modified: 2022.0224