Facts about Sedna
- 09
No moon has ever been detected orbiting Sedna, making it one of the few known dwarf planets in the solar system without a natural satellite.
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Sedna's reddish coloration suggests a surface composition rich in methane ice and other organic compounds, distinguishing it from most other distant solar system objects.
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Incan mythology inspired the name Sedna, honoring the Inuit goddess of the sea and marine life who rules the ocean depths.
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Beyond Neptune's orbit, Sedna's mysterious gravitational influences suggest an undiscovered massive object may be shepherding this distant dwarf planet through the outer solar system.
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Sedna's orbit is so extreme that it reaches only 76 astronomical units from the sun at its closest approach, yet travels nearly 936 astronomical units at its farthest distance.
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Sedna's surface temperature plummets to approximately minus 240 degrees Celsius, making it one of the coldest known objects in our solar system.
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Discovered in 2003 by astronomers Michael Brown, Chad Trujillo, and David Rabinowitz, Sedna remains so distant that sunlight takes approximately 11 hours to reach its surface.
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Sedna's extremely elongated orbit takes approximately 11,400 Earth years to complete one full revolution around the sun.
- 01
At approximately 995 kilometers in diameter, Sedna ranks as the third-largest known dwarf planet in our solar system after Eris and Pluto.