Makemake

Makemake is a dwarf planet located in the Kuiper belt. The Kuiper belt is a wide disk of icy bodies found beyond the orbit of Neptune.

As the largest member of the classical Kuiper belt, Makemake is a major object in the outer solar system. It is also the fourth largest trans-Neptunian object. This means it is a significant body located past the orbit of Neptune. Scientists classify it as a plutoid. A plutoid is a specific type of dwarf planet that orbits beyond Neptune.

This classification helps astronomers organize the many different objects found in the distant reaches of our solar system.

Astronomers discovered Makemake on March 31, 2005.

The discovery was made by American astronomers Michael E. Brown, Chad Trujillo, and David Rabinowitz. They used the 1.22-meter Samuel Oschin telescope at the Palomar Observatory in California. The team was searching for large objects in the trans-Neptunian region. While they found the object in March, Michael Brown identified it as exceptionally bright on April 3, 2005. The discovery process was quite dramatic. The team had previously found other large objects like Eris. They originally planned to announce Makemake after Eris. However, another team in Spain announced the discovery of the object Haumea first. To avoid being scooped, Brown contacted the Minor Planet Center to announce the discovery of both Eris and Makemake on July 29, 2005.

The discovery of these large objects changed how we view our solar system. In August 2006, the International Astronomical Union (IAU) created a new definition for a planet. This new definition led to the reclassification of Pluto as a dwarf planet. Makemake was the first object named under the new IAU procedures for dwarf planets. The name Makemake comes from the myths of the Rapa Nui people of Easter Island. In these myths, Makemake is the creator of humanity and a god of fertility. Before it had this official name, the team used the nickname "Easterbunny" because of the time of year it was found. They also used the computer codename "K05331A." The name Makemake was officially approved by the IAU in July 2008.

Makemake has a very specific shape and size. It is a nearly spherical object. This shape occurs because it is in hydrostatic equilibrium. This means its gravity is strong enough to pull it into a round shape. However, its rotation causes it to be slightly oblate. This means it is a bit flattened at its poles.

The average diameter of Makemake is approximately 1,430 kilometers. This diameter is about 60% of Pluto's diameter. It is also about 11% of Earth's diameter. In terms of mass, Makemake is about 20% the mass of Pluto. It is the fourth-most massive trans-Neptunian object, following Eris, Pluto, and Haumea. Its surface gravity is quite low, at about 3.6% of Earth's gravity.

The environment on Makemake is driven by its unique composition and orbit. The surface is highly reflective and covered largely by frozen methane. This ice is stained a reddish-brown color by compounds called tholins.

Scientists have also detected gaseous methane near the surface. It is not yet clear if this gas is part of a permanent atmosphere. It might instead come from temporary outgassing. There is also evidence of cryovolcanism. Cryovolcanism is a process where ice and gas move from the interior to the surface. This activity leads scientists to suspect that a subsurface ocean of liquid water might exist beneath the crust.

Makemake's movement through space is also quite complex. It follows a moderately elliptical orbit around the Sun.

It takes about 307 years to complete one full orbit. The orbit is quite tilted, with an inclination of 29 degrees relative to the ecliptic plane. This tilt is much higher than the orbits of the major planets. Makemake also has one known satellite, though it has not been named. The orbit of this moon suggests that Makemake has a high axial tilt. This high tilt, combined with its elliptical orbit, likely causes extreme seasons on the surface. Makemake is currently near its aphelion, which is the farthest point from the Sun. It will reach this point again in May 2033.

Even though Makemake is a major object, it remains difficult to study closely. It is so far from Earth that it looks like a star-like point of light through a telescope. No space probe has ever visited Makemake. Because of this, we do not have any high-resolution images of its surface. Scientists are very interested in sending a probe to explore this world. They want to investigate the geological activity and the potential liquid ocean. Studying Makemake helps us understand the "dynamically hot" population of the Kuiper belt. These are objects that were likely scattered by Neptune's gravity during the early history of the solar system.