Epiphany Somewhere, something incredible is waiting to be discovered. ~ Carl Sagan

1Feb/140

Makemake and Eris

Makemake is the god of fertility and creator of humanity in the mythology of the Rapa Nui people of the island of Rapa Nui in Polynesia. Actually, Rapa Nui forms one of the vertex of the triangle that defines Polynesia. Rapa Nui is in the middle of nowhere, with the nearest inhabited island almost 2000 km away with the nearest continental point almost 3500 km away.

The Dutch explorer. Jacob Roggeveen reached the Rapa Nui island on April 5th, 1722, Easter Sunday. It was named Easter Islands, the name with which we know the islands popularly now. The islands are known for its large stone statues called Moai. I bet you have seen images of these statues and wondered what they are.

Makemake

Makemake

Moai

Moai

 

Polynesian triangle with Rapa Nui represented by 3.

Polynesian triangle with Rapa Nui represented by 3.

 Eris is the Greek Goddess of strife and discord. The story goes that due to her nature to cause discord, she was the only Goddess not invited for the marriage of Peleus and Thetis (Parents of Achilles. Remember Achilles as played by Brad Pitt in Troy?). She became angry and decided to crash the party. She brought with her an apple (Why does it always have to be an apple???) with "To the fairest one" written on it. This obviously caused trouble with all the other Goddess claiming they deserved it. The decision to adjudicate was put on Zeus who wisely delegated that to Paris, son of Priam (Paris - Remember Orlondo Bloom from Troy? The coward, useless guy??). Hera offered Paris ownership of all known world, Athena offered him wisdom and the abilities of the greatest warrior while Aphrodite offered him the love of the most beautiful woman in the world. In his infinite stupidity, Paris chose Aphrodite. Aphrodite gives him the love of Helen who is already married to King Menelaus of Sparta thus sowing the roots of destruction of Troy in the Trojan war.

In the month of March of 2005, 31st March to be precise (4 days after Easter Sunday), the team of astronomers at the Palomar Observatory of Caltech led by Michael Brown discovered the object seen in the below image.

Makemake through the eye of Hubble

Makemake through the eye of Hubble

This was code-named Easterbunny and it has a diameter about 2/3 that of Pluto with an orbital period of 310 years. With the astronomical naming convention of naming classical Kuiper Belt Objects (KBO) after mythological names associated with creation, Mike Brown and his team decided to name the object Makemake after the Easter Island God of creation. Its complete name is 136472 Makemake with the number being a sequential number.

In January of the same year, the same team of astronomers from Caltech also discovered what they called Xena or Planet X. The way these objects are discovered is by comparing successive images taken of the same region of space on successive days. Since the star move very slowly, they would appear stationary in these images while planets, dwarf planets and other objects that are closer would appear to move. Now the space is so huge, the objects so dim and the number of objects that are visible so large that this is a very difficult task. Sophisticated computer programs are written that compare these images and identify possible matches. These possible matches also number in thousands due to problem with telescope (eg, dust particle on mirrors), the imaging device (eq, photographic plates not properly handled, problem in digital cameras) etc that these matches would still have to be visually inspected by an astronomer to classify them as possible matches. Below is the image that shows Xena in three successive images.

Movement of Eris

Movement of Eris

 Now the problem with Xena is that it is larger than Pluto (around 12 km in diameter) and 27% more massive than Pluto. When the discovery of Xena was announced along with the discovery of Makemake, it created a huge controversy. Is Xena a planet? It is larger than Pluto and if size is the criteria then it should be classified as a planet and be Planet X or the tenth planet. Can Makemake be also classified as Planet, it is just 2/3 the size of Pluto? Can Ceres, in the asteroid belt, also classified as a Planet? These discoveries led to much "discord and strife" in the international astronomical community finally forcing the International Astronomical Union (IAU) to define planets as

(1) A "planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

This resulted in Pluto relegated from the elite club of Planets to that of dwarf planets along with Xena, Sedna and Makemake. Due to the effect that Xena had, its discoverer Michael Brown appropriately named it Eris (136199 Eris).

Eris with its satellite Dysnomia

Eris with its satellite Dysnomia

 Fun Facts: Makemake has an orbital period of 310 years meaning it takes 310 years to complete one orbit around the Sun. Eris has an orbital period of 560 years (Aphelion around 97 AU) and at its most distance from the Sun, is almost twice as far away as Pluto is and believe me Pluto is far far away (Aphelion around 48 AU). New Horizons space probe, currently travelling at 14.8 km/s was launched in 2006 and will reach Pluto only by 2015. At its current speed, it can fly around earth in less than an hour. That should give you a perspective on how far away these objects are. Now the same Caltech team of Michael Brown also discovered 90377 Sedna. Now if you think Eris is very distant then Sedna is far, far, far, far away. Its aphelion is 937 AU, almost ten times as distant as Eris is and its orbital period is 11400 years! The last time Sedna was in the same position as today, humanity still had more than a thousand year to domesticate sheep and start agriculture (8000 BCE). 

Sedna

Sedna

Orbit of Sedna - Red ellipse is the orbit of Sedna while the purple ellipse is the orbit of Pluto. Note how Pluto's orbit intersect that of Neptune (blue circle) making Pluto nearer to the Sun than Neptune at some points of its orbit.

Orbit of Sedna - Red ellipse is the orbit of Sedna while the purple ellipse is the orbit of Pluto. Note how Pluto's orbit intersect that of Neptune (blue circle) making Pluto nearer to the Sun than Neptune at some points of its orbit.