NASA scientists recently discovered that Pluto's sister planet, Makemake, is not alone. Using the Hubble telescope, the astronomers found that the dwarf planet has its own moon.

According to Wired, Makemake belongs to the five dwarf planets officially recognized by the International Astronomical Union (IAU) along with Ceres, Pluto, Eris, Haumea. However, Makemake was not known to have a moon -- until now.

Makemake's own moon, dubbed as the S/2015 (136472) or simply MK 2, is estimated to be 160 kilometers in diameter and was seen orbiting Pluto's sister 13,000 miles from its surface, Space.com reports.

The moon was picked up by Hubble's Wide Field Camera 3 back in April 2015. This latest discovery in the icy dwarf planet will help a lot in observing and exploring Makemake's characteristics.

“Our preliminary estimates show that the moon’s orbit seems to be edge-on, and that means that often when you look at the system you are going to miss the moon because it gets lost in the bright glare of Makemake,” said Alex Parker who spearheaded the analysis of Hubble's captured images. “The discovery of this moon has given us an opportunity to study Makemake in far greater detail than we ever would have been able to without the companion.”

According to NASA, discovering a satellite or moon in a dwarf planet will enable scientists to determine the planet's mass system and know how it evolved by simply observing its orbit. Space.com says that if a moon's orbit is "tightly circular," this means that the planet could have originated from a big impact eons ago. However, if the orbit is elliptical, this means that the moon was once a flying object that was attracted by the planet.

NASA also notes that MK 2's surface could be charcoal black, despite the fact that Makemake is a bright icy object. This might mean that MK 2 is very small and could not hold on to brighter objects, such as Makemake. It might also have a similar composition with other comets and objects in the Kuiper Belt.

Team leader Marc Buie of the Southwest Research Institute said, “This new discovery opens a new chapter in comparative planetology in the outer solar system."