Buzz
Located in the Kuiper Belt—an expansive ring of icy bodies and volatile materials lying beyond Neptune's orbit—almost every known dwarf planet in our solar system resides there, except for one. Pluto, the largest of these celestial bodies, is closely followed by Eris. Next up is the intriguing Makemake, a distant and highly reflective planet. From a staggering distance of 4.26 billion miles, much of Makemake remains a mystery, but scientists are gradually uncovering its secrets. Here are a few lesser-known facts about this dynamic world.
1. MAKEMAKE MEASURES ONLY THREE TIMES THE LENGTH OF THE GRAND CANYON.
Makemake's orbit takes it a half-billion miles further from the Sun than Pluto. A single day on Makemake lasts almost as long as one on Earth—22.5 hours—yet its orbit around the Sun is a much slower affair, with one Makemakean year stretching across 305 Earth years. With a diameter of approximately 880 miles, Makemake is around two-thirds the size of Pluto and about three times the length of the 277-mile-long Grand Canyon. While this might not sound particularly remarkable, it's worth noting that hundreds of thousands of objects orbit the Sun, placing Makemake among the 25 largest in our solar system.
2. IT SHINES WITH IMPRESSIVE BRIGHTNESS.
Even though Makemake is smaller than Pluto, it ranks as the second most luminous object in the Kuiper Belt. This high reflectivity is due to its surface being coated with a significant amount of methane and ethane ice, with small frozen methane pellets possibly dotting its icy exterior. While it likely appears reddish-brown, its vast distance from Earth makes it difficult to confirm its exact color.
3. IT WAS ONCE CALLED "EASTERBUNNY" …
In 2005, Caltech's Mike Brown discovered Makemake just after Easter. (Brown is also credited with discovering the dwarf planets Eris and Haumea.) Before it received its official name, Brown’s team affectionately referred to it as "Easterbunny." Astronomers originally gave it the provisional designation "2005 FY9."
4. … BEFORE IT WAS NAMED AFTER A GOD FROM EASTER ISLAND.
In 2008, Easterbunny/2005 FY9 was officially classified as a dwarf planet by the International Astronomical Union (IAU). While selecting a name for the object, Brown was inspired by the nearby holiday and its connection to Easter Island, which was first visited by a European around Easter 1722. This led him to the island’s people and their religious beliefs. Makemake, the creator god of the Rapa Nui people of Easter Island, was chosen as the planet’s name.
5. MAKEMAKE CONTRIBUTED TO PLUTO'S DEMOTION TO DWARF PLANET STATUS.
The discovery of Makemake, along with Eris just months earlier (which is larger than Pluto), prompted astronomers to reevaluate the definition of a planet. A planet must orbit the Sun, have sufficient mass to form a spherical shape, and clear its orbital path of other objects. Eris, Makemake, Pluto, and Haumea all fail to meet these criteria in various ways. For Pluto, the issue is its inability to clear its orbit. After intense discussions, the IAU introduced the category of 'dwarf planet' to classify these bodies—including Pluto. (Thanks to Makemake.)
6. MAKEMAKE'S SURFACE IS HIGHLY VOLATILE.
Makemake is more than just a spherical rock floating through space; in many respects, it mirrors Pluto. Its surface is largely composed of methane, a highly volatile substance also found on Pluto. (A 'volatile' compound reacts to temperature changes.) According to Alex Parker, a senior research scientist at the Southwest Research Institute in Boulder, Colorado, "The processes on Pluto are driven by the movement of volatiles across the surface as temperatures fluctuate. If a world like Makemake has a surface dominated by volatiles, it likely experiences dynamic processes similar to those on Pluto."
7. ITS MOON WAS DISCOVERED ONLY RECENTLY.
In the image above, Makemake appears to have no moon. This is because its moon was only identified in 2016 by Parker [PDF], who detected it in data from the Hubble Space Telescope. "It was actually a pretty obvious satellite," Parker shared with Mytour. "I didn’t need to dig too deeply into the data; it just popped out immediately, clear as day."
He adds: "As soon as I found it, I felt a bit deflated because I was sure others who had analyzed the data before me would have spotted it too—and that I’d be late to the discovery. My first question to the principal investigator was, 'Hey, have you seen the moon in the Makemake data?' I was certain the answer would be, 'Yes.' But instead, I was told, 'There's a moon in the Makemake data?' It was thrilling to realize that the discovery I thought others had made was actually something I was the first to observe."
The moon is officially named S/2015 (136472), with the nickname MK 2. It is more than 1300 times dimmer than Makemake and is estimated to be just 100 miles in diameter.
8. ASTRONOMERS ARE WORKING TO MAP MAKEMAKE USING ITS MOON.
Makemake's moon is more than just a celestial body; it serves as a valuable tool for astronomers. As the 105-mile-wide moon (almost twice the length of the Panama Canal) and its parent planet pass in front of each other, scientists can use the resulting changes in brightness to map the surface of Makemake. "Just as we had preliminary maps of Pluto before we visited, we can use the moon's passage in front of Makemake as a means of mapping it," explains Parker.
More specifically, when one object passes in front of the other, parts of the hidden object can be isolated. Astronomers can then measure the brightness of only the isolated part of the object, rather than the whole body. By mapping darker and lighter regions, scientists can determine terrain features on the object. Although this method won’t identify mountains, it can highlight areas that warrant further study and detailed modeling.
"Makemake can be thought of as a sort of precursor to Pluto before the New Horizons mission. We are just beginning to see what it might look like," says Parker. "It could turn out to be a dynamic and active world, and that's what makes it so intriguing."
9. MUCH ABOUT MAKEMAKE REMAINS UNKNOWABLE.
There is still much uncertainty about how Makemake's day-night cycle influences its surface features and processes (including geological activity and potential interactions between the atmosphere—if it has one—and the surface). The origins and history of its moon remain mysterious, presenting further intriguing challenges for scientists. Researchers studying planetary formation and the motions of celestial objects are revising their models to explain why moons are such a defining characteristic of dwarf planets—especially the peculiar ones—considering that half of the terrestrial planets in the solar system, like Mercury and Venus, lack moons.
"Why are moons so common among the dwarf planets in the Kuiper Belt? At this stage, every large object in the Kuiper Belt, except for one, has at least one moon," Parker explains. "Some have two. Some have as many as five. So, if you propose a process for the formation of these planets, such as accretion, one of the inevitable outcomes of that process is that these planets will all end up with at least one moon."
10. THERE ARE NO PLANS TO VISIT MAKEMAKE … YET.
No missions have been launched to Makemake as of now, although the New Horizons spacecraft, after completing its Pluto reconnaissance, has ventured further into the Kuiper Belt to examine at least one more object. On Earth, planetary scientists are developing strategies for future missions to the Kuiper Belt. New propulsion technologies are being created by engineers to allow for more scientific exploration in single missions. Looking further ahead, orbiter missions are planned to revisit previously studied bodies and conduct more detailed investigations. "With the immense variety in the Kuiper Belt," Parker says, "it will be an exciting era as we begin to uncover the secrets of these distant worlds."
