Dwarf Planets: The Lesser Worlds

Summary

The video explores the fascinating world of dwarf planets and minor planets within our solar system. It discusses the reclassification of Pluto and other celestial bodies, highlighting the complex features and intriguing properties of these distant worlds. The video delves into the composition, discovery, and unique characteristics of notable dwarf planets like Ceres, Eris, Haumea, and Makimaki, as well as objects in the Kuiper Belt such as Arakoth. Through detailed analysis and exploration, it reveals the unexpected complexity and diversity of these far-reaching celestial bodies.

Takeaways

• 🌍 Our solar system consists of eight main planets, four rocky terrestrial planets, and four gas giants.
• 🌐 Beyond the orbits of the main planets, there are numerous small icy worlds known as minor planets, including Pluto, which was reclassified as a dwarf planet in 2006.
• 🔍 The term 'minor planet' is broad and includes any astronomical object orbiting the sun or another star that is not a planet or a comet.
• 🌟 The International Astronomical Union (IAU) redefined the criteria for a planet in 2006, adding the requirement that a planet must clear its orbital path, leading to the reclassification of Pluto as a dwarf planet.
• 🪐 Dwarf planets, like Pluto, are large enough to be rounded by their own gravity but do not dominate their surrounding space.
• 🌕 Ceres, the first dwarf planet ever discovered and visited, is the largest object in the asteroid belt and is composed mostly of rock and water ice.
• 🌌 The Kuiper Belt, beyond the orbit of Neptune, is a vast region of icy objects and debris, home to many dwarf planets and other small bodies.
• 🌑 Pluto, once considered the ninth planet, has a complex landscape with ice mountains, valleys, craters, and a possible subsurface ocean.
• 🌠 Eris, the second largest dwarf planet, is the most massive and has a moon named Dysnomia, indicating its size and mass.
• 🌈 Haumea, another dwarf planet, has an elongated shape and a ring system, making it the first trans-Neptunian object with a ring.

Q & A

What are the two main types of planets in our solar system?

The two main types of planets in our solar system are the rocky terrestrial planets and the gas giants.

What is the term used to describe small icy worlds orbiting in the outer reaches of the solar system?

These small icy worlds are known as minor planets.

Why was Pluto reclassified as a dwarf planet in 2006?

Pluto was reclassified as a dwarf planet because it is too small to be considered on the same level as the Earth or Saturn and does not clear out its orbital path.

What is the difference between a planet and a dwarf planet according to the International Astronomical Union's definition?

A planet must orbit the sun, be in hydrostatic equilibrium (spherical shape due to its own gravity), and clear out its orbital path. A dwarf planet meets the first two criteria but does not clear out its orbital path.

How many known minor planets are there in the solar system?

There are almost 800,000 known minor planets in the solar system.

What is the significance of Ceres in the asteroid belt?

Ceres is the largest object in the asteroid belt, accounting for about a third of the belt's total mass, and was reclassified as a dwarf planet in 2006.

What evidence suggests that Ceres might have had a subsurface ocean?

Shiny bright patches on Ceres' surface, which are deposits of magnesium salt residue, indicate that there might have been liquid water eruptions from a subsurface ocean.

What is the Kuiper Belt and what is its significance?

The Kuiper Belt is a thick, rotating disk of icy objects and debris beyond the orbit of Neptune. It is significant because it is thought to contain well-preserved artifacts from the early solar system.

What are the characteristics of Pluto's landscape?

Pluto's landscape consists of vast mountain ranges made of solid ice, valleys, craters, flat plains, and ice caps of frozen methane. It is thought to have a rocky core, a water ice mantle, and an icy crust.

What is the significance of the discovery of Eris, Haumea, and Makemake?

The discovery of these dwarf planets prompted the International Astronomical Union to redefine the criteria for what constitutes a planet, leading to the reclassification of Pluto and the recognition of these bodies as dwarf planets.

Outlines

00:00

🌍 Our Solar System's Diverse Planets

This paragraph introduces the structure of our solar system, highlighting the terrestrial planets close to the sun, which are primarily composed of rock, and the gas giants further out. It also discusses the reclassification of Pluto from a planet to a dwarf planet in 2006 due to its inability to clear its orbital path. The paragraph emphasizes the existence of minor planets, which are astronomical objects that orbit the sun but are neither planets nor comets. The International Astronomical Union's definition of a planet includes criteria such as orbiting the sun, being in hydrostatic equilibrium (having a spherical shape due to gravity), and clearing its orbital path.

05:01

🪐 Dwarf Planets: The Lesser-Known Celestial Bodies

The focus shifts to dwarf planets, which are not as large as traditional planets but still possess intriguing properties. Ceres, the first dwarf planet discovered, is highlighted as an example. Initially mistaken for a comet and later classified as an asteroid, Ceres was reclassified as a dwarf planet due to its size and composition. It is the largest object in the asteroid belt and is believed to contain a significant amount of water, possibly even a subsurface ocean. The paragraph also discusses the exploration of Ceres by NASA's Dawn spacecraft and the implications of its findings on our understanding of dwarf planets.

10:02

🌌 The Kuiper Belt: A Treasure Trove of Icy Objects

This paragraph delves into the Kuiper Belt, a vast region beyond the orbit of Neptune that is densely populated with icy objects. The objects in the Kuiper Belt are thought to be well-preserved remnants from the early solar system, providing insights into its formation. The paragraph describes the discovery and exploration of Pluto, which was once considered the ninth planet but was reclassified as a dwarf planet. The New Horizons mission's flyby of Pluto revealed a complex landscape with ice mountains, valleys, and a possible subsurface ocean. The paragraph also touches on the unique features of Pluto, such as its heart-shaped region, Sputnik Planitia, and its five moons.

15:03

🌑 Pluto's Complex Landscape and Atmosphere

The paragraph explores Pluto's diverse landscape and its atmospheric conditions. Despite its small size, Pluto has a surprisingly detailed surface with ice mountains, valleys, and plains. It is thought to have a rocky core and a water ice mantle. Pluto's thin atmosphere, composed of nitrogen, methane, and carbon monoxide, is influenced by its low gravity. The paragraph also discusses the possibility of a subsurface ocean on Pluto and the implications of its active surface features, such as the lack of impact craters in the Sputnik Planitia region.

20:04

🌠 The Discovery and Properties of Other Dwarf Planets

This paragraph discusses the discovery and properties of other dwarf planets in the Kuiper Belt, such as Eris, Haumea, and Makemake. Eris, the most massive dwarf planet, was discovered in 2003 and is similar in size to Pluto. Haumea, with its elongated shape, is thought to be the result of a collision and has a ring system. Makemake, discovered in 2005, is smaller than Haumea and has a surface covered in frozen methane. The paragraph also touches on the debate that led to the reclassification of Pluto and the criteria for defining a planet, which now includes clearing its orbital path.

25:07

🌈 Arakoth: The Smallest and Most Primitive Object Explored

The final paragraph introduces Arakoth, a small solar system body discovered in 2014 and visited by the New Horizons spacecraft. Arakoth is unique for its double-lobed shape, resembling a snowman. Its red color indicates that it has been exposed to cosmic radiation and ultraviolet light for a long time, suggesting that it is ancient and well-preserved. The composition of Arakoth, which includes methanol water ice and organic molecules, is distinct from other objects explored. The paragraph concludes by reflecting on the complexity and resilience of dwarf planets and the vast potential for discovery in the Kuiper Belt and beyond.

Keywords

💡Terrestrial Planets

Terrestrial planets are defined as those primarily composed of rock and metal, similar to Earth. In the video, it mentions that the four terrestrial planets in our solar system are closest to the sun and are made mostly of rock. These planets, including Earth, are distinct from the gas giants that lie further out.

💡Gas Giants

Gas giants are large planets composed mainly of hydrogen and helium, found further from the sun than terrestrial planets. The script refers to these planets as 'huge balls of hydrogen and helium', indicating their vast size and different composition compared to terrestrial planets.

💡Minor Planets

Minor planets, as described in the video, are small icy worlds orbiting in the outer reaches of the solar system. They are not as large as conventional planets and were previously known as asteroids. The term encompasses a broad classification of astronomical objects that orbit the sun but are not planets or comets.

💡Dwarf Planets

Dwarf planets are a subcategory of minor planets that are large enough to be rounded by their own gravity but do not dominate their surrounding space. Pluto is highlighted as an example, having been reclassified from a planet to a dwarf planet in 2006. The video discusses the properties of dwarf planets, emphasizing their smaller size and unique characteristics.

💡Hydrostatic Equilibrium

Hydrostatic equilibrium is a state where an object is shaped into a sphere by its own gravity. The video explains that, according to the International Astronomical Union's definition, a planet must be in hydrostatic equilibrium. This criterion is crucial for distinguishing planets from other celestial bodies.

💡Ceres

Ceres is the first dwarf planet ever discovered and visited. It was initially mistaken for a comet and later classified as a planet, before being reclassified as a dwarf planet. The video discusses Ceres' composition, its location in the asteroid belt, and its significance in understanding the solar system's history.

💡Kuiper Belt

The Kuiper Belt is a region beyond the orbit of Neptune that contains a vast number of icy objects and debris. The video describes it as a 'thick, rotating disk' similar to the asteroid belt but much larger and more densely populated. It is a significant area for studying the early solar system and contains many dwarf planets and Kuiper Belt Objects (KBOs).

💡Pluto

Pluto, once considered the ninth planet of the solar system, is a central focus of the video. It is a dwarf planet and a Kuiper Belt Object. The script discusses its reclassification, its complex landscape, and its unique features like the 'heart' region and its moons. Pluto's discovery and subsequent reclassification sparked debates about the definition of a planet.

💡Eris

Eris is the second largest dwarf planet in the solar system and the most massive. The video mentions its discovery and the subsequent debate it caused regarding the definition of a planet. Eris is significant as it challenged the traditional view of what constitutes a planet, leading to Pluto's reclassification.

💡Haumea

Haumea is a dwarf planet discovered by Mike Brown, noted for its elongated egg shape and rapid rotation. The video describes it as possibly being the result of a collision, which could explain its unusual shape. Haumea's discovery contributed to the reevaluation of what qualifies as a planet.

💡Makimaki

Makimaki is a dwarf planet discovered by Mike Brown, slightly smaller than Haumea. The video discusses its unusual orbit and the fact that it is one of the brightest trans-Neptunian objects. Makimaki's discovery further expanded the understanding of dwarf planets and their diverse characteristics.

Highlights

The solar system consists of eight planets, four rocky terrestrial planets, and four gas giants.

Pluto was reclassified as a dwarf planet in 2006, losing its status as the ninth planet.

Minor planets, including dwarf planets, are astronomical objects orbiting the sun that are not planets or comets.

There are nearly 800,000 known minor planets in the solar system, archived by the Minor Planet Center.

The term 'minor planet' has evolved to include dwarf planets and small solar system bodies (SSSBs).

Ceres, discovered in 1801, is the first dwarf planet ever discovered and visited.

Ceres is located in the asteroid belt and is composed mostly of rock and water ice.

Ceres is thought to have a subsurface ocean and pockets of liquid water.

The Kuiper Belt is a vast region beyond the orbit of Neptune, containing icy objects and debris.

Pluto, a Kuiper Belt Object, was discovered in 1930 and has a complex and mysterious landscape.

Pluto's surface temperatures can fall as low as -240 degrees Celsius, causing gases to freeze.

Pluto's heart, the Tombaugh region, is a unique area with a smooth icy surface and no impact craters.

Eris is the second largest and most massive dwarf planet in the solar system.

Haumea has an elongated egg shape and is believed to be the result of a large collision.

Makimaki is a small, bright trans-Neptunian object with an unusual orbit.

Aracoth, discovered in 2014, is a small solar system body with a double-lobed shape.

Dwarf planets exhibit complex processes such as temporary atmospheres, ring systems, and tectonic activity.

Transcripts

right now

unless you're somehow watching this from

space you are situated on a planet

a giant sphere of material and heat

ours is made mostly of rock as are the

three other planets in our backyard

further away from the sun lie four huge

balls of hydrogen and helium

in different states these constitute the

eight planets of the solar system

four rocky terrestrial planets and four

gas giants

however this is far from the full

picture

the solar system is also home to another

type of world

between and beyond the orbits of the

eight conventional planets

lie dozens and dozens of small icy

worlds

orbiting in the outer reaches of the

solar system

these are known as minor planets or at

least they used to be

the best example is of course pluto

in 2006 pluto was reclassified as a

so-called

dwarf planet voiding its status as the

solar system's ninth planet which it had

held for many decades

pluto ultimately is just too small to be

considered on the same level as the

earth or saturn

however there is more to it than just

pluto's size

the actual story behind pluto's

reclassifications started with the

discoveries of several similar remote

minor planets

and now pluto sits among a family of

almost worlds

dwarf planets which despite being much

smaller than the earth

still exhibit fascinating and unlikely

properties

today we will experience these frozen

far out worlds first hand

the term minor planet is a broad

classification

defined as any astronomical object in

orbit around the sun or another star

which is neither a planet

nor a comet most of the time this is

because it is either too small to be a

planet

or it doesn't have the same impact on

its surroundings as the other planets do

while pluto is the obvious one there are

almost eight 800

000 known minor planets in the solar

system alone

which are archived by the minor planet

center

up until about 15 years ago the terms

minor planet

planetoid and asteroid were all used

synonymously

referring to a body not large or round

enough to be considered a conventional

planet

however since the term was coined we

have reached and studied the outer solar

system

a place where rocky and icy material is

much more abundant

leading to discoveries which have

blurred the lines between what can be

considered a planet and what can't

as a result the terminology has become

more complicated over time

and the need for clarifications arose

and so in 2006 the international

astronomical union voted to amend their

definition of a planet

before this a planet had to satisfy two

simple criteria

the first being that it needs to orbit

around the sun obviously

the other thing is that it needs to be

in hydrostatic equilibrium

in other words large and heavy enough

that it becomes rounded by its own

gravity

giving it a spherical shape

under these criteria pluto was

discovered and named the solar system's

ninth planet

which it remained for many decades but

with the definition change

came a third criterion now a planet must

also

clear out its orbital path as they

travel around the sun

the large planets either clear out or

consume material in their way

dispersing the rubble of the early solar

system and clearing themselves a region

of space which they dominate and

influence

under this revised definition however

pluto doesn't fit the bill

the reason being because it orbits

within a large band of debris near the

outer rim of the solar system

and thus doesn't clear out its region of

space

thus it lost its planetary status to the

disappointment of many

following the rule change the iau then

reclassified the term minor planet into

two new sub-categories

dwarf planets and small solar system

bodies

or sssbs dwarf planets

like pluto are the nearly worlds which

are large enough to be rounded but don't

dominate their surrounding space

a small solar system body is anything

else that isn't a comet

like a large asteroid or the micro

satellites which orbit such

asteroids or perhaps the icy objects

beyond the reaches of neptune

known as trans-neptunian objects or tnos

as a result the term minor planet has

become outdated

but it is still used to encompass both

types

today however we are going to be

focusing for the most part on dwarf

planets

while not as large or structured as

their planetary counterparts

they can still house astounding

properties the likes of which we never

expected to find on worlds so far away

from the sun

and while most of these worlds lie

billions of kilometers away

and are thus very difficult to reach and

study we do have one relatively close to

us

the first dwarf planet ever to be

discovered and visited

ceres ceres was discovered in 1801

by giuseppe piazzi who noted it while he

was searching for stars

initially he mistook it for a comet and

named it series ferdinandia

however within a year astronomers had

identified it as another planet

and shortened its name to ceres named

after the roman goddess of corn and

harvests

it lies over 400 million kilometers away

from the sun

within the asteroid belt a ring

consisting of pieces of rock between the

orbits of mars and jupiter

after initially being mistaken for a

comet and then for a planet

ceres was reclassified as just another

asteroid among the many others in the

belt

however it sticks out as an outlier

against its rocky neighbours

at just under 1000 kilometers in

diameter it is by far the largest object

within the belt

and also accounts for about a third of

the belt's total mass

and so it was among a host of objects to

be reclassified as dwarf planets in

2006.

putting aside the anthropocentric

terminology however

it seems strange doesn't it a dwarf

planet here

in a sparsely populated belt where

nothing else like it exists

too large to be an asteroid but too

small to be another planet

and so in 2015 we visited the world

in an attempt to better understand its

origins

nasa's dawn spacecraft made flybys of

series

sending back detailed images and giving

us clues to its past

it is composed of mostly rock and water

ice its core

and mantle are thought to constitute a

layer of ice which

if it exists would mean that ceres has

more water than the earth

in a solid form at least but buried

beneath its icy cratered surface

is thought to have pockets of liquid

water

surviving from a subsurface ocean which

once flowed

above ground on the surface of the dwarf

planet

it is now thought that ceres is the

remains of an embryonic planet

a small rocky body which was

accumulating material

in the early solar system just like the

earth

it is now believed that ceres may have

had an ocean of magnesium salt water

flowing on its surface billions of years

ago however its destiny was cut

short when its neighbouring planets

jupiter in particular

scattered and consumed the vast majority

of material in the area

the same material that grew the

terrestrial planets and the gas giants

as such ceres was unable to grow larger

and so was far too small to hold on to

its primordial atmosphere

and so the budding proto-planet died

and was cast into the asteroid belt

destined to float silently among rubble

and debris

when its atmosphere was lost to space so

too was the ocean

and its remnants are now buried beneath

the surface in its last surviving

pockets

we can see evidence of these liquid

water pockets in these shiny bright

patches on the surface

these highly reflective mounds are

actually deposits of magnesium salt

residue

left over from liquid water eruptions in

the mantle

which spilled out onto the surface

whether anything could survive in these

underground pockets of water remains a

mystery

one thing's for sure though ceres is a

true gem

hidden within a dead and desolate region

of the solar system

one of the reasons there aren't any

other dwarf planets in the asteroid belt

is because the belt is so sparsely

populated

most of its material has been depleted

and the few objects that remain

are scattered millions of kilometers

apart

however significantly further away than

the asteroid belt beyond the orbit of

all eight of the planets

lies another far larger belt of material

the kuiper belt the kuiper belt is a

thick

rotating disk of icy objects and debris

similar in structure to the asteroid

belt but much larger

and more densely populated the objects

in the kuiper belt are thought to have

formed very early on in the solar

system's life

rocks began appearing out of the dust

around the young sun

which condensed to form the planets and

any primordial rocky pieces that were

not consumed were scattered

and much of it drifted and settled into

this massive belt

unfathomably far away from the sun

because the objects within are so far

away from the sun's light

they have only been warmed and

irradiated slightly in the billions of

years since their formation

and so are thought to be well-preserved

artifacts which can allow us to examine

what the solar system was like back then

the kuiper belt begins at just beyond

the orbit of neptune

around 30 astronomical units away so

that's 30 times further than the earth

is from the sun

and it extends out to around 50 times

further away

thus it is so remote and vast that it is

a place that we have only just begun to

explore and understand

objects within the kuiper belt are

referred to quite simply

as kuiper belt objects or kbos

scattered within the kuiper belt's

expanse are hundreds of millions of

cometary nuclei

hundreds of thousands of objects larger

than 100 kilometers in diameter and

perhaps hundreds of small

cold dwarf planets which have yet to be

discovered

and crucially because they all exist and

orbit within the bounds of this belt

they do not clear out their orbital

paths or dominate the space around them

effectively excluding them from being

planets

however that doesn't stop them from

having intriguing planet-like features

such as transient atmospheres which

exist as gas

in an atmospheric layer when faced with

the light of the sun

before collapsing down into frost on the

surface during the night

this brings us to our most distant

honorary planetary neighbour

pluto pluto

was discovered in 1930 and it is named

after the roman god of the underworld

it is classed as a kuiper belt object

and a dwarf planet today

but it was long considered to be the

solar system's ninth planet

it is smaller than all eight of the

solar system's main planets

and orbits considerably further out

averaging a distance of about 39

astronomical units it orbits the sun

in both an elliptical and tilted orbit

which can take it as far away as 50

astronomical units

to the very distant outer edge of the

kuiper belt

its small size low visibility and sheer

distance from the earth makes it a very

tricky world to study

until about five years ago we only had

very low detail

observations of the dwarf planet but all

this changed in 2015

when nasa's new horizons mission flew by

pluto

revealing it in brilliant detail for the

first time

and what a revelation it was the data

we've collected from pluto since has

revolutionized our ideas on the

complexity of worlds this far away from

their parents star

despite being small around 2 370

kilometers in diameter

pluto still has a surprisingly detailed

and mysterious landscape

consisting of vast mountain ranges made

of solid ice

some several kilometers high it also has

valleys craters flat plains and even ice

caps of frozen methane

it is thought to have a rocky core

surrounded by a water ice mantle

topped by an icy crust because it is so

far away

its surface temperatures can fall to as

low as -240 degrees celsius

so cold that nitrogen and methane gases

freeze down onto its surface

and into frozen nitrogen ice sheets

across its vast plains

[Music]

for the most part pluto is a scarred

cratered world

except for in one unusual place like

nowhere else found in the solar system

for this we have to look to the tombau

region also known as pluto's heart

it is a large double lobed plane of

smooth volatile ice sheets

its western lobe is known as sputnik

planitia

here there are no impact craters instead

the smooth icy surface is intersected by

cracks which crisscross the ice sheet

showing evidence of convection currents

below the surface

even at this size and distance from the

sun part of pluto's crust

is active we're not sure exactly what

drives this convection

but it is responsible for gently turning

the nitrogen ice sheet over

resurfacing it and keeping it fresh thus

explaining the lack of craters

one theory is that this active nitrogen

ice sheet floats atop

a buried subsurface ocean of liquid

water

that has existed for billions of years

which was exposed by a huge impact

collision this collision would have torn

off a huge chunk of pluto's crust

resulting in radioactive decay within

the basin at left

which may be the elusive heat source

that is churning the ice sheet to this

day

during the day pluto's volatile ices

sublimate directly

into a gas which expands into an

atmospheric layer of nitrogen

methane and carbon monoxide

because it has such low gravity its

atmospheric layer is held down much less

tightly than it is on earth

allowing its atmosphere to extend much

further out into space

and as the new horizon spacecraft flew

away from pluto

it turned back and saw this inflated

atmospheric layer in all of its

breathtaking glory

pluto also has no less than five moons

the largest sharon is about half the

size of pluto itself

making it the largest moon relative to

its parent in the solar system

and also one of the closest so close in

fact that the gravitational center of

the pluto system

is not actually pluto itself and thus

pluto and sharon are generally referred

to as a barycenter

the other four moons nyx hydra styx

and kerberos are all much smaller

resembling fragments more so than moons

we're not sure how the pluto sharon

system came to be

but the leading theory is that it was

formed by a collision of kuiper belt

objects

pluto and sharon have similar densities

which suggests that they may have once

been part of a single body

for now though that remains just a

theory

we talked earlier about the iau's

reclassifications in 2006

but what actually was it that prompted

the debate between what constitutes a

planet or not

it wasn't pluto itself because pluto was

accepted as a planet for a long time

it was actually a series of minor planet

discoveries between 2003

and 2005 that were what got people

questioning the definition

these discoveries were made by mike

brown at palomar observatory

and in the years leading up to the iau's

decision in 2006

he identified three new dwarf planets

lurking beyond the orbit of pluto in the

kuiper belt

these worlds were eris haumea

and makimaki at present

none of these worlds have been visited

and so these far-out images are as close

as we've managed to get

however we have been able to deduce and

ascertain some of their properties by

using techniques

such as spectral analysis of these three

newfound dwarf planets it was eris that

caused the stir

eris is the second largest dwarf planet

in the solar system after pluto

but it is also the most massive it is

estimated to be about 2

320 kilometers in diameter

only about 50 kilometers less than the

dwarf planet's sibling

and so virtually the same size when

viewed on a global scale

scientists think that it is probably

rocky and icy with the terrain similar

to the one found on pluto

it was first spotted by brown in 2003

and was later confirmed in 2005

and when it was it was set to be

classified as the solar system's 10th

planet however this raised an

interesting dilemma

if we allow pluto eris and any other

dwarf planets to be

planets then before long the solar

system would have 20 or 30 planets

the vast majority of which would just be

rounded kuiper belt objects

and so this led to the addition of the

third criterium in the iau's definition

of a planet

effectively excluding all kuiper belt

objects from consideration both pluto

and eris were classified as dwarf

planets

and eris was named after the greek

goddess of strife and discord

we don't know much about what its

surface is actually like

purely because it is so far away is over

three times further away than pluto

and its orbit takes it far beyond the

kuiper belt to the cusp of interstellar

space at almost

100 astronomical units away

because it is so far away from the sun

gases like nitrogen and methane will

have almost certainly frozen down onto

its surface like they do on pluto

so perhaps the two worlds are more

similar than we yet realize

one thing we do know for certain though

is that eris has one small moon

named dysnomia it has a nearly circular

orbit around eris

completing a lap of the dwarf planet

once every 16 days

this satellite has allowed us to make

estimations of the dwarf planet's mass

which is how we managed to conclude that

it is more massive than pluto

and thus the most massive dwarf planet

in the solar system

but unfortunately that's about it and it

will probably be a while before we can

get any closer

as this world is so far away and remote

that

at present is simply too far beyond our

reach to study up close

[Music]

the second dwarf planet discovered by

brown was haumea

it was first noted in late december of

2004

originally being nicknamed santa before

being officially named after the

hawaiian goddess of fertility and

childbirth

it is about a third as massive as pluto

and it's hard to know whether to class

it as a dwarf planet or a small solar

system body

unlike the others mentioned so far it is

not a spherical world

instead it has an elongated egg shape

estimated to be around 1 600 kilometers

in diameter

its rapid rotation and high albedo are

clues as to its origins

and we now believe that the minor planet

is perhaps the largest constituent of a

collection of trans-neptunian objects

left over from a large collision of

debris

before this haumea was perhaps a rounded

world more analogous to pluto and

eris but this collision is thought to

have blown off haumea's icy mantle

resulting in a relatively unstructured

and unshapely body

composed of silica rock we cannot make

out the surface in much detail

but its colour changes as it rotates

relative to us

indicating that there is a dark patch on

its surface like on pluto

it also has two very small moons hiyaka

and namaka which are also thought to be

remnants of the same collision

perhaps its most unusual and captivating

feature

is that it has a faint ring around it

making it the first trans-neptunian

object with a ring system to be

discovered

the ring's width is about 70 kilometers

and it extends the system's total

diameter to around 2

300 kilometers wide pretty impressive

complexity for such a small

immature world

[Music]

finally we have makimaki the third dwarf

planet to be discovered by brown

in 2005. it is slightly smaller than

haumea

about 1 400 kilometers in diameter

but unlike the former it is rounded by

its own gravity

while small it is the brightest

trans-neptunian object after pluto

but it managed to evade detection for

many years thanks to its unusual orbit

which lies out of sync with the solar

system's ecliptic plane

at this moment in time it is over 50

astronomical units away

near the outer edge of the kuiper belt

which is about as far away from the sun

as it gets along its journey

analysis of its spectral data revealed

that its surface is most likely covered

in grains of frozen methane

there is also evidence for small

quantities of nitrogen ice

but nowhere near as much as on pluto

indicating that it has lost its nitrogen

over time

the presence of methane and nitrogen

together suggests that the world may

have a transient atmosphere like pluto

if so this would explain the nitrogen

depletion

because makimaki is particularly small

it cannot retain

its atmosphere when it expands

especially the nitrogen

methane is lighter than nitrogen but it

freezes at much higher temperatures

meaning much less methane thaws when

exposed to the sun

nitrogen on the other hand is easily

excited by the sun's light

and only the difference of a few degrees

causes it to sublimate into a gas

where it is lost to space thanks to the

low escape velocity of the dwarf

makimaki also has a tiny moon nicknamed

mk2

like the others it is thought to have

formed from a collision

but unlike its parent its body is as

dark as charcoal

perhaps because it is simply too small

to have been able to retain

its reflective ices which sublimated and

escaped into space

long ago along with makimaki's nitrogen

[Music]

ice

i don't plan on doing a christmas video

this year but because it's december

here's a christmas themed minor planet

arakoth is a small solar system body

about a billion and a half kilometers

further from the sun than pluto

it was discovered in 2014 using the

hubble telescope

at a time when the new horizons team

were looking for one final body for the

spacecraft to visit

following the completion of the pluto

mission the year after arakoth isn't

anything special

or at least it seemed like it back then

and it was thought to be nothing more

than a large asteroid

but it was selected for the new horizons

flyby because

it was the closest and easiest object

for the spacecraft

to reach given its trajectory and fuel

constraints

as such aracoth is both the smallest and

most primitive object

ever studied up close by a flyby however

when the probe arrived it found

something totally unexpected

arakoth is double lobed meaning it has

two rounded segments which are connected

and one happens to be larger than the

other and so it appears like a snowman

albeit a very flat one we're not sure

how arakoth came to be like this

but the two segments probably formed

independently nearby to one another

before being pulled into orbit around

each other eventually connecting and

then gently merging

what we do know is that the body is very

red redder than pluto

and in fact it is the reddest body in

the outer solar system discovered to

date

this redness occurs over time when the

surface minerals of a body are zapped by

cosmic radiation and ultraviolet light

from the sun

indicating that it is both ancient and

well preserved in its primordial form

its composition differs wildly to most

objects explored prior with scientists

finding evidence of methanol water ice

and even

organic molecules from the data

in any case arikoff is by far the oldest

and loneliest snowman in the entire

solar system

as it takes its solitary 293 year

periodic orbit around the sun

dwarf planets are truly remarkable

little worlds

who would have thought that such complex

processes temporary atmospheres

ring systems and even tectonic activity

would be playing out so incomprehensibly

far away from the warmth of the sun

we certainly didn't expect it before we

reached pluto

and as is usually the case with space

exploration

what we found when we arrived completely

blew our ideas out of the water

and with nearly 800 000 small solar

system bodies out there

just imagine what else could be hidden

in the recesses of the kuiper belt

contemplating such ideas makes you

realize just how vast

detailed and intricate the solar system

really is

and that's just our star system imagine

what else could exist in the galaxy if

ours is anything to go by

then dwarf planets probably vastly

outnumber the planets of the galaxy

and they are more resilient and complex

worlds than we ever thought possible

you