Researchers Suggest Dwarf Planets Should Be Reclassified

 

Dwarf planets are the vagabonds of the solar system outcasts that keep their own crazy orbits and their secrets away from our prying eyes Pluto was once considered a planet but is now relegated to the netherworld of nomads that are still being defined counted and catalogued welcome to Science Reads in today's article we dig into seven strange dwarf planets that to one degree or another we did not know existed what mysteries do they harbor and what can they tell us about our own origins the more we learn about these strange little worlds the more interesting they become some have multiple moons and at

 least one beyond Neptune has a ring

 gone are the days of our tidy little

 neighborhood having nine planets and an asteroid belt that circles the sun

 in a predictable and orderly fashion

 there are increasingly strange worlds being found close by and there's so much we can learn from them there is an ongoing debate in the scientific community over which objects are categorized as dwarf planets so we will look at both official entries and very viable candidates any accounting of strange dwarf planets starts with Haumea an odd thing over 2 billion kilometers or 1.24 billion miles beyond Pluto named for the Hawaiian goddess of childbirth this occupant of the Kuiper belt is roughly the same size as the former knife planet with a notable difference Haumea is very much shaped like an egg or some say a football called Santa by one of two teams who claim the 2003 discovery palmea is one of the fastest rotating objects in our solar system a day on this little wonder lasts only three hours and 55 minutes and astronomers believe its rapid spinning caused the distortion of its shape some theorize a collision with a gigantic object started Haumea's rapid spinning billions of years ago that same collision may explain the dwarf planet's two moons Hiyaka and Namaka which were discovered in 2005. so a person standing at Haumea's equator would see six sunrises and sunsets in every 24-hour period along with two moons and it gets even more interesting in January 2017 astronomers in six european countries used 12 telescopes to watch haumea pass between earth and a dim red star the eclipse gave researchers the dwarf planet's size and shape but it also revealed quite a surprise to the observers a ring astronomers jose luis ortiz and pablo santo sans of the institute of astrophysics of andalusia in grenada spain along with her colleagues reported the startling ring to be 70 kilometers or 43 miles wide and about 2 290 kilometers or 1422 miles from haumea center so we have a dwarf planet shaped like an egg or a football with two moons and a ring at its widest haumea is roughly the size of pluto wouldn't a flyby be quite interesting and now on to a cosmic rivalry eris gets much of the blame for pluto's demotion from planet status to dwarf planet and it all started on january 8 2005 when astronomers announced their discovery of a pluto-sized world billions of miles past neptune's orbit it was originally thought to be larger than the then ninth planet which ignited debate over what exactly qualifies a body in the solar system to be deemed planetary so in 2006 the international astronomical union iau concluded that pluto is only a dwarf planet and belongs in a different category than its eight former colleagues thank you eris it took another decade for nasa's new horizons mission to reveal eris is actually smaller than pluto oops scientists after the 2005 discovery named the new world xena after the fictional tv character and its tiny moon gabriella after her sidekick but the iau the next year chose to call the dwarf planet heiress after the greek goddess of discord as in discord over pluto's relegation to less than planetary status so it's fitting the tiny moon would now be dysnomia aerys daughter and the demon goddess of lawlessness in greek mythology both are part of the kuiper belt of thousands of icy little worlds that occupy a disc-like zone beyond neptune a single day on eris is quite similar in length to one on earth totaling 25.9 hours a year is a much different story with a dwarf planet needing 557 earth years to journey around the sun and its orbit is very eccentric inclined about 44 degrees to the plane of the solar system and far past eris comes our next entry sedna rises much further out in the theoretical ord cloud a spherical cloud of small icy bodies over one thousand times further from the sun than neptune's orbit in the 2003 paper announcing its discovery sedna was described as the first observed body from the inner oort cloud the sun is so far away that if you

 were standing on sedna's surface

 you could block it out with the head of a pin the discoverers named it for the inuit goddess of sea and marine animals also known as

 the goddess or mistress of the sea

 only mars is redder than this dwarf planet which is three-fourths the size of pluto and likely the largest object in the solar system discovered since the former 9th planet in 1930 as for its orbit it takes roughly 11 400 earth years to travel around the sun many astronomers believe this dwarf planet was not formed where it is but was possibly knocked out of the york cloud by a passing star a sort of cosmic game of marbles its intense red issue is thought to be from the presence of tholin's organic compounds found on other solar system occupants by new horizons these compounds rain down onto the surface after interaction with cosmic rays or ultraviolet light in atmospheric methane the term tholin was coined by carl sagan and a colleague in a 1979 paper with a rotation every 22.5 hours this frozen world has a similar day to both earth and mars and like earth it has a single known moon but that's where the similarities end being so distant in the kuiper belt there's not much specifically known about makemake but research suggests it is covered with bright ices and also littered with methane pellets its moon mk2 has a radius of only 80 kilometers or 50 miles and is as black as charcoal and its discoverers first nicknamed the planetoid easter bunny its official name makimaki is the name of the creator of humanity and god of fertility in the mythology of the south pacific island of rapa nui also known as easter island ceres has the triple distinction of being the largest object in the asteroid belt between mars and jupiter the first asteroid found all the way back in 1801 and the only dwarf planet in the inner solar system originally categorized as an asteroid ceres was deemed a dwarf planet in 2006 by planetary standards ceres is quite small with a radius of only 476 kilometers or 296 miles however it's by far the largest object in the asteroid belt thus its dwarf planet designation and while there's no evidence of an atmosphere data gleaned from nasa's dawn spacecraft shows a water-rich world with a crust dominated by the frozen remains of a global ocean also fascinating are several bright spots discovered on ceres by don in 2015. turns out these are salt deposits likely from evaporated liquids that

 percolated up to the dwarf planet's surface triton makes our list due to its

 possible former status as a dwarf planet though now it's relegated to being an icy moon of neptune but its particular orbit and similarities to pluto lead some astronomers to suspect it was originally a dwarf planet in the kuiper belt that was captured by neptune as for that peculiar orbit triton is the only large moon in the solar system to have a retrograde orbit moving in the opposite direction of its planet's rotation many also believe triton has a liquid

 water ocean beneath its surface

 this presents a long list of interesting possibilities and makes the possibly

 once upon a time dwarf planet among

 the most inhabitable worlds we know of and finally we reach pluto for 76 years pluto breathed the rarefied air of being one of nine planets in our solar system but that all changed with its reclassification in 2006 now it must settle for being the largest dwarf planet and the reigning king of the kuiper belt sometimes called the third zone of the solar system pluto's orbit is in resonance with neptune circling the sun twice for every three orbits by neptune however its orbit is not in the same plane with the planets but inclined at a 17 degree angle and more oval-shaped in fact pluto gets physically closer to uranus than it ever is to neptune the new horizons measurements from nasa's 2015 exploration of the dwarf planet confirmed pluto to be larger than eris though slightly less massive its thin atmosphere is composed largely of nitrogen with a bit of methane and carbon monoxide like a comet the atmosphere expands as pluto gets closer to the sun and collapses the further it moves away and as a defender of pluto will proudly proclaim the dwarf planet has five moons which is more than the four closest planets to the sun combined and people who miss pluto's planetary

 status just received a bit of good news a study released in december 2021 in the journal icarus by a team of planetary researchers calls for pluto to be re-elevated to a planet but not to stop there the 2006 iau decision established three criteria a planet must achieve one it is in orbit around the sun two it has sufficient mass to

 assume hydrostatic equilibrium

 a nearly round shape and three it has

 cleared the neighborhood around its orbit but the brand new study claims the iau's definition of a planet is based on astrology not science philip metzger planetary physicist at the university of central florida and the study's lead author says we think there's probably over 150 planets in our solar system he also noted that eris and makimake were discovered by 2006 and the new definition was designed to exclude them medscar adds that we are continuing to call pluto a planet in our papers we are continuing to call titan and triton and some other moons by the term planet basically we are ignoring the iau so are all these strange dwarf planets and geologically active moons going to be reclassified as planets not only will that make every kid's quiz over the solar system much more difficult but according to the author of how i killed pluto and why it had it coming the iau made the correct call with the 2006 resolution michael brown caltech astronomer and author says the iau fixed an embarrassing mistake that had been perpetrated for generations the solar system is now sensible perhaps but it's certainly a more interesting neighborhood with all our eccentric relatives be they planets or not so what do you think about our seven strange dwarf planets and what they bring to our solar system what questions would you like to see the james webb space telescope or a future flyby answer about our odd neighbors tell us in the comments