Makemake
Dwarf planet in the Kuiper belt discovered in 2005.
Makemake, designated minor-planet number 136472, is a dwarf planet located in the Kuiper belt, a region of icy objects beyond Neptune. It ranks as the fourth largest dwarf planet and trans-Neptunian object in the Solar System, with a diameter about 60% of Pluto’s. The object was discovered on March 31, 2005, by American astronomers Michael E. Brown, Chad Trujillo, and David Rabinowitz at Palomar Observatory. Because it was one of the largest bodies found by this team, its discovery helped push the International Astronomical Union to redefine Pluto as a dwarf planet in 2006.
Makemake’s surface strongly resembles Pluto’s: it is very reflective, mostly covered in frozen methane, and tinted reddish-brown by tholins. The dwarf planet has a single known moon, which remains unnamed. That moon’s orbit indicates Makemake rotates with a high axial tilt, leading to extreme seasonal changes. Evidence of geochemical activity and cryovolcanism has been found, raising the possibility of a subsurface ocean of liquid water. Gaseous methane has been detected around Makemake, though scientists are unsure whether it forms a stable atmosphere or comes from temporary outgassing.
No spacecraft has visited Makemake, so high-resolution images of its surface do not exist. From Earth, even through a telescope, it appears only as a star-like point of light. Because of its geological activity and potential subsurface ocean, researchers have expressed interest in sending a probe to study it.
**History**
**Discovery** Makemake was discovered in 2005 by the same American team—Brown, Trujillo, and Rabinowitz—that was searching for large objects beyond Neptune. Their survey, begun in 2001, used a charge-coupled device camera on the 1.22-meter Samuel Oschin telescope at Palomar Observatory. The discovery images were taken on March 31, 2005, but Brown did not spot the object until April 3, when he noticed it was unusually bright.
Months earlier, the team had found Haumea and Eris, both thought to be at least as large as Pluto. They originally planned to announce Makemake after Eris’s announcement in October 2005. That schedule changed when a Spanish team led by José Luis Ortiz Moreno announced Haumea on July 27, 2005. Brown realized his team’s observing logs—containing positions for Haumea, Eris, and Makemake—had been unintentionally made public and accessed from Ortiz’s institution. Fe
- discovered
- March 31, 2005
- discoverers
- Michael E. Brown, Chad Trujillo, David Rabinowitz
- location
- Kuiper belt
- diameter
- ~1,430 km (60% of Pluto)
- known_for
- Fourth largest dwarf planet; evidence of cryovolcanism and potential subsurface ocean
- named_after
- Makemake, creator deity of the Rapa Nui people
Lore & Background
Makemake was discovered in 2005 by a team of American astronomers during their search for large objects beyond Neptune. The discovery images were taken on March 31, 2005, using the 1.22-meter Samuel Oschin telescope at Palomar Observatory, but the object was not identified until April 3, 2005, when Michael E. Brown found it in his inspection of the images. The team had previously discovered Haumea and Eris, and originally planned to delay Makemake's announcement until after Eris's in October 2005. However, when a Spanish team announced their own discovery of Haumea on July 27, 2005, Brown feared his team's discoveries would be scooped and contacted the Minor Planet Center on July 29, 2005, to announce both Eris and Makemake. The announcement of these Pluto-sized objects prompted widespread debate that led to the International Astronomical Union's redefinition of planet and reclassification of Pluto as a dwarf planet in August 2006.
Makemake is named after the creator of humanity and god of fertility in the myths of the Rapa Nui people of Easter Island. Before its naming, it was known by the provisional designation 2005 FY9 and the nickname 'Easterbunny' given by Brown's team due to its discovery shortly after Easter. The name was approved and announced by the IAU in July 2008. Makemake has one known moon, which has not been named. Its orbit suggests a high axial tilt, implying extreme seasons. The surface is highly reflective, covered largely by frozen methane and stained reddish-brown by tholins. Evidence of geochemical activity and cryovolcanism has led scientists to suspect a subsurface ocean of liquid water. Gaseous methane has been detected, though it is unclear whether it forms an atmosphere or comes from temporary outgassing.
Reader's Guide
Makemake holds significance as one of the largest known trans-Neptunian objects and a key figure in the reclassification of Pluto as a dwarf planet. Its discovery, along with that of Eris, forced the International Astronomical Union to formally define the term 'planet' in 2006, establishing the new category of dwarf planet. Makemake was the fourth object announced as a dwarf planet after Ceres, Pluto, and Eris, and the first named under new IAU procedures for objects expected to be dwarf planets. As the largest member of the classical Kuiper belt, it provides insight into the early Solar System's dynamics, particularly the gravitational scattering of objects by Neptune. Its surface composition—frozen methane and tholins—resembles Pluto's, and evidence of cryovolcanism and a potential subsurface ocean makes it a target for future space probe exploration. No high-resolution images exist because no probe has visited it; it appears as a star-like point even through telescopes. Scientists have expressed desire to send a probe due to its geological activity and potential subsurface ocean. Makemake's legacy lies in its role in planetary classification debates and its promise for understanding icy worlds beyond Neptune.
Did You Know?
- Makemake has a diameter about 60% that of Pluto.
- Its surface is covered largely by frozen methane and stained reddish-brown by tholins.
- Makemake has one known moon, which has not been named.
- Gaseous methane has been detected around Makemake, but it is unclear if it forms an atmosphere or comes from temporary outgassing.
More in Discoveries by Michael E. Brown 1-24
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