The Top 5 Planets in the Solar System with the Longest Years

  Planet Length of Year
(equivalent in Earth years)
Surface Area
1 Eris 557 years 295 days 78,500,000 km2
2 Makemake 310 years 33 days 6,300,000 km2
3 Pluto 247 years 256 days 16,650,000 km2
4 Neptune 164 years 298 days 7,640,800,000 km2
5 Uranus 84 years 4 days 8,115,600,000 km2
Tags: Space & The Universe, Top 5 Longest

Sources:  Top 5 of Anything Research 2014, NASA:

List Notes: Length of year is period of orbit around the sun in the equivalent amount of Earth years and days. Planets included in this list include two dwarf planets (Eris & Makemake).
Planets in the Solar System with the Longest Years
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 Facts
  1. For comparison the surface area of the Earth is 510,065,700 km2. (a.)
  2. Makemake was discovered in March 2005 by a team of astronomers led by Mike Brown and officially became a dwarf planet in July 2008. Designated 2005 FY9 soon after its discovery by Brown's team at Caltech in 2005, it was renamed Makemake for the creator of humanity in the Rapa Nui mythology of Easter Island. (b).
  3. Eris, a newly discovered dwarf planet (announced in 2005), was first nicknamed "Xena" after the lead fictional character in the 1995-2001 television series "Xena: Warrior Princess." Officially it is catalogued as 2003 UB313. The diameter of Eris is 2,384 kilometers (1,490 miles), which is about half the width of the United States. Eris is the most distant solar system object ever seen. (c.)
  4. The dwarf planets in our solar system are Ceres, Pluto, Eris, MakeMake and Haumea the largest of which is Eris which is three quarters the size of Earth's moon. In 2006 the International Astronomical Union made the controversial decision to reclassify Pluto as a dwarf planet. The new definitions of a planet included that it must have its own orbit around the sun, as Pluto orbits in the Kuiper Belt with other similar objects it could no longer continue to be seen as a planet.
  5. Venus and Mercury are the only planets in the solar system with years of shorter duration than Earth years (Venus: 225 days, Mercury 88 days).
Top 5 facts sources:
  1. NASA. (2011). "Solar System Information" Retrieved Jan 30th, 2011 from: http://solarsystem.nasa.gov/planets/index.cfm
  2. NASA. (2008). "Astronomy Picture of the Day" Retrieved Jan 30th, 2011 from: http://apod.nasa.gov/apod/ap080716.html
  3. NASA. (2006). The Star Witness: "Xena The Tenth Planet?". Retrieved Jan 30th, 2011.

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