A Visual Introduction to the Dwarf Planets in our Solar System
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A Visual Introduction to the Dwarf Planets in our Solar System



A Visual Introduction to the Dwarf Planets of our Solar SystemA Visual Introduction to the Dwarf Planets of our Solar System

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Pluto and the Introduction of Dwarf Planets

Since its discovery in 1930, Pluto has been a bit of a puzzle.

For starters, not only is Pluto smaller than any other planet in the solar system, but it’s also smaller than Earth’s moon. It also has an extremely low gravitational pull at only 0.07 times the mass of the objects in its orbit, which is just a fraction of the Moon’s own strength.

At the same time, Pluto’s surface resembles that of terrestrial planets such as Mars, Venus or the Earth, yet its nearest neighbors are the gaseous Jovian planets such as Uranus or Neptune. In fact, Pluto’s orbit is so erratic that it led many scientists to initially believe that it originated elsewhere in space and the Sun’s gravity pulled it in.

These qualities have challenged the scientific view of Pluto’s status as a planet for years. It wasn’t until the discovery of Eris in 2005, one of many increasingly identified trans-Neptunian objects (objects beyond the planet Neptune), that the International Astronomical Union (IAU) defined criteria for classifying planets.

With Eris and other trans-Neptunian objects sharing similar characteristics with Pluto, the definition for dwarf planets was created, and Pluto got downgraded in 2006.

So what are dwarf planets, how do they differ from “true” planets and what are their characteristics?

The History of Dwarf Planets

A dwarf planet is a celestial body that almost meets the definition of a “true” planet. According to the IAU, which sets definitions for planetary science, a planet must:

  1. Orbit the Sun.
  2. Have enough mass to achieve hydrostatic equilibrium and assume a nearly round shape.
  3. Dominate its orbit and not share it with other objects.

Dwarf planets, along with not being moons or satellites, fail to clear the neighborhoods around their orbits. This is the primary reason why Pluto lost its status: because it shares part of its orbit with the Kuiper belt, a dense region of icy space bodies.

Based on this definition, the IAU has recognized five dwarf planets: Pluto, Eris, Makemake, Haumea, and Ceres. There are four more planetary objects*, namely Orcus, Sedna, Gonggong and Quaoar, that the majority of the scientific community recognize as dwarf planets.

Six more could be recognized in the coming years, and as many as 200 or more are hypothesized to exist in the Outer Solar System in the aforementioned Kuiper belt.

Ceres is the earliest known and smallest of the current category of dwarf planets. Previously classified as an asteroid in 1801, it was confirmed to be a dwarf planet in 2006. Ceres lies between Mars and Jupiter in the asteroid belt, and it is the only dwarf planet that orbits closest to Earth.

Here is a brief introduction to the most recognized dwarf planets:

NameRegion of the
Solar System
Orbital period
(in years)
Mean orbital
speed (km/s)
relative to
the Moon
OrcusKuiper belt (plutino)2474.7591026%1
CeresAsteroid belt4.617.994027%0
PlutoKuiper belt (plutino)2484.74237768%5
HaumeaKuiper belt (12:7)2854.531560≈ 45%2
QuaoarKuiper belt (cubewano)2894.51111032%1
MakemakeKuiper belt (cubewano)3064.41143041%1
GonggongScattered disc (10:3)5543.63123035%1
ErisScattered disc5583.62232667%1

Interesting Facts about Dwarf Planets

Here are a few interesting facts about the dwarf planets discovered in our solar system:

Ceres loses 6kg of its mass in steam every second

The Herschel Space Telescope observed plumes of water vapor shooting up from Ceres’ surface; this was the first definitive observation of water vapor in the asteroid belt. This happens when portions of Ceres’ icy surface warm up and turn into steam.

A day on Haumea lasts 3.9 hours

Haumea has a unique appearance due to its rotation, which is so rapid that it compresses the planet into an egg-like shape. Its rotational speed and collisional origin also make Haumea one of the densest dwarf planets discovered to date.

Makemake was named three years after its discovery in 2005

Makemake’s discovery close to Easter influenced both its name and nickname. Before being named after the creator of humanity and god of fertility in the mythos of the Rapa Nui (the native people of Easter Island), Makemake was nicknamed “Easter bunny” by its discoverer Mike Brown.

Eris was once considered for the position of the 10th planet

Eris is the most massive dwarf planet in the solar system, exceeding Pluto’s mass by 28%. As such, it was a serious contender to become the tenth planet but failed to meet the criteria set out by the IAU.

Pluto is one-third ice

The planet’s composition makes up two-thirds rock and one-third ice, mostly a mixture of methane and carbon dioxide. One day on Pluto is 153.6 hours, approximately 6.4 Earth days, making it one of the slowest rotating dwarf planets.

Exploratory Missions and New Planets on the Horizon

With newer technology rapidly available to the scientific community and new exploratory missions getting more data and information about trans-Neptunian objects, our understanding of dwarf planets will increase.

Nestled in the asteroid belt between Mars and Jupiter, the asteroid Hygiea remains a controversy. Hygiea is the fourth largest object in the asteroid belt behind Ceres, Vesta, and Pallas and ticks all the boxes necessary to be classified as a dwarf planet.

So what’s holding back Hygiea’s confirmation as a dwarf planet? The criterion for being massive enough to form a spherical shape is in contention; it remains unclear if its roundness results from collision/impact disruption or its mass/gravity.

Along with Hygiea, other exciting dwarf planets could be soon discovered. Here is a quick rundown of some serious contenders:

Potential Dwarf Planets Under Investigation

120347 Salacia

Discovered in 2004, it is a trans-Neptunian object in the Kuiper belt, approximately 850 kilometers in diameter. As of 2018, it is located about 44.8 astronomical units from the Sun. Salacia’s status is in contention because its planetary density is arguable. It is uncertain if it can exist in hydrostatic equilibrium.

(307261) 2002 MS4

With an estimated diameter of 934±47 kilometers, 2002 MS4 is comparable in size to Ceres. Researchers need more data to determine whether 2002 MS4 is a dwarf planet or not.

(55565) 2002 AW197

Discovered at the Palomar Observatory in 2002, it has a rotation period of 8.8 hours, a moderately red color (similar to Quaoar) and no apparent planetary geology. Its low albedo has made it difficult to determine whether or not it is a dwarf planet.

174567 Varda

Varda takes its name after the queen of the Valar, creator of the stars, one of the most powerful servants of almighty Eru Iluvatar in J. R. R. Tolkien’s fictional mythology. Varda’s status as a dwarf planet is uncertain because its size and albedo suggest it might not be a fully solid body.

(532037) 2013 FY27

This space object has a surface diameter of about 740 kilometers. It orbits the Sun once every 449 years. Researchers need more data on the planet’s mass and density to determine if it is a dwarf planet or not.

(208996) 2003 AZ84

It is approximately 940 kilometers across its longest axis, as it has an elongated shape. This shape is presumably due to its rapid rotation rate of 6.71 hours, similar to that of other dwarf planets like Haumea. Like Varda, it remains unknown if this object has compressed into a fully solid body and thus remains contentious amongst astronomers regarding its planetary status.

*Note: The IAU officially recognizes five dwarf planets. We include four additional dwarf planets widely acknowledged by members of the scientific community, especially amongst leading planetary researchers like Gonzalo Tancredi, Michael Brown, and William Grundy. There are many more potential dwarf planets not listed here that remain under investigation.

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Ranked: The 35 Vehicles With the Longest Production Runs

Successful cars come in many shapes and sizes. See which ones have stood the test of time in this infographic.



Visualizing the Longest Vehicle Production Runs

Over the automotive industry’s 100+ year history, companies such as Ford, Chevrolet, and Mercedes-Benz have produced some truly iconic cars.

Whether they’re designed for excitement, luxury, or just simple transportation, these vehicles offer a set of features that make them highly desirable to consumers. The most successful models will undergo numerous revisions over time, sometimes sticking around for many decades.

To learn more, this graphic from Alan’s Factory Outlet lists the 35 vehicles with the longest production runs of all time. Here are the top 10 below.

BrandModel NameClassProduction Run (years)
🇺🇸 ChevroletSuburbanSUV86
🇺🇸 FordF-SeriesPickup truck74
🇩🇪 VolkswagenTransporterVan71
🇯🇵 ToyotaLand CruiserSUV70
🇺🇸 ChevroletCorvetteSports car68
🇩🇪 Mercedes-BenzS-ClassSedan67
🇯🇵 ToyotaCrownSedan66
🇯🇵 NissanSkylineSedan64
🇬🇧 MiniMiniHatchback62
🇩🇪 Porsche911Sports car58

As we can see, successful models come in many shapes and sizes, and from a variety of manufacturers. Below, we’ll take a deeper dive to learn more about what makes these cars special.

Ford F-Series

Ford began selling its first pickup truck in 1925, which was essentially a Model T with a flatbed in the rear. This layout was very useful because it enabled people to transport cargo, raw materials, and other items with relative ease.

Then, in 1948, Ford introduced the F-series pickup. The truck became one of Ford’s most well-known and profitable models, and is currently in its 14th generation.

While the fundamental shape of the F-series hasn’t changed, Ford’s best-selling model owes much of its success to its constant innovation and technological improvements.

In 2015, the F-150 became the first fullsize pickup to feature an all-aluminum body. This reduced the truck’s weight by as much as 500 pounds, resulting in better fuel economy and driving dynamics.

Ford is also credited with bringing turbocharged engines into the mainstream (within the pickup segment). This first-mover advantage gave the F-Series a competitive edge in terms of fuel efficiency and torque.

Chevrolet Corvette

First introduced in 1953, the Chevrolet Corvette is regarded as America’s most iconic sports car. It has a reputation for offering similar performance as its more expensive foreign rivals, and combines unique styling elements with a successful motorsport background.

For most of its history, the Corvette was a rear-wheel drive coupe with a V-8 engine placed in the front. It also featured pop-up headlights for several generations, but the design was eventually phased out due to stricter regulations.

Evolution of the Corvette

Chevrolet drastically changed the formula of the Corvette for its eighth generation, which launched in 2020. The engine is no longer in the front of the car, but instead, placed directly behind the occupants.

C8 interior cross section

This mid-engine layout results in a Corvette with significantly different proportions than its predecessors. Because a bulk of the car’s weight is now located more centrally, the C8 should (in theory) offer better traction and balance.

Few cars have undergone such large changes to their fundamental design philosophy, but the move appears to have worked—production is far from meeting demand.

Mercedes-Benz S-Class

The S-Class from Mercedes is widely recognized as the global benchmark for full-size luxury sedans. Since its introduction in the 1950s, the S-Class has continuously introduced new innovations that improve comfort and safety.

  • The 1959 S-Class (dubbed W111) was the first production car with crumple zones front and rear. Crumple zones are structural elements that absorb the impact of a collision.
  • The 1978 S-Class (W116) introduced electronic anti-lock brakes (ABS). This system prevents tires from locking up under sudden braking and is included on every modern car.
  • The 1991 S-Class (W140) was the first car to feature double-glazed windows, which improves insulation while reducing road noise.
  • The 2021 S-Class (W223) introduced the world’s first rear-seat airbag.

One of the most important aspects of a luxury car is its interior, and the S-class has come a long way since its first iteration.

The interior of the latest S-Class features active ambient lighting that can visually reinforce any warnings generated by the car’s driving assistance systems. The cabin also features MBUX Interior Assist, which can read motion commands (such as hand movements) by the driver.

The car’s center console is dominated by a single large screen—a trend that was first introduced by the Tesla Model S.

Big Changes in Store

Global governments have announced a ban on the sale of new gasoline cars by as early as 2030. This foreshadows a great shift towards battery power and gives automakers the opportunity to reimagine their most iconic models.

For example, the Ford Mustang Mach-E is an all-electric SUV that borrows both the name and styling of the brand’s famous pony car. The company also recently launched an electric version of the F-150, called the F-150 Lightning.

German brands are taking a different approach by creating a completely new range for their EV models. This includes the Audi e-tron, BMW i, and Mercedes EQ lineups. This implies that their existing gasoline-powered models could be coming to an end.

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A Deep Dive Into the World’s Oceans, Lakes, and Drill Holes

A unique and entertaining graphic that compares the depth of the world’s lakes and oceans, as well as the deepest holes ever drilled.



Today’s chart is best viewed full-screen. Explore the high resolution version by clicking here.

Sailors have been circumnavigating the high seas for centuries now, but what could be found beneath the sunlit surface of the ocean remained a mystery until far more recently. In fact, it wasn’t until 1875, during the Challenger expedition, that humanity got it’s first concrete idea of how deep the ocean actually was.

Today’s graphic, another fantastic piece by xkcd, is a unique and entertaining look at everything from Lake Superior’s ice encrusted shoreline down to blackest, inhospitable trench (which today bears the name of the expedition that first discovered it).

The graphic is packed with detail, so we’ll only highlight a few points of interest.

Deep Thoughts with Lake Baikal

Deep in Siberia, abutting a mountainous stretch of the Mongolian border, is the one of the most remarkable bodies of water on Earth: Lake Baikal. There are a number of qualities that make Lake Baikal stand out.

Depth: Baikal, located in a massive continental rift, is the deepest lake in the world at 1,642m (5,387ft). That extreme depth holds a lot of fresh water. In fact, an estimated 22% of all the world’s fresh water can be found in the lake.

Age: Baikal (which is listed as a UNESCO World Heritage Site) is estimated to be over 25 million years old, making it the most ancient lake on the planet.

Clarity: Interestingly, the water in the lake is exceptionally clear. In winter, visibility can extend over 30m (98ft) below the surface.

Biodiversity: The unique ecosystem of Lake Baikal provides a home for thousands of plant and animal species. In fact, upwards of 80% of those species are endemic, meaning they are unique to that region.

Who is Alvin?

Since 1964, a hard-working research submersible named Alvin has been helping us better understand the deep ocean. Alvin explored the wreckage of RMS Titanic in 1986, and helped confirm the existence of black smokers (one of the weirdest ecosystems in the world).

Though most of the components of the vessel have been replaced and upgraded over the years, it’s still in use today. In 2020, Alvin received an $8 million upgrade, and is now capable of exploring 99% of the ocean floor.

We know more about the surface of Venus than the bottom of the ocean. The potential for discovery is huge.– Anna-Louise Reysenbach, Professor of Microbiology, PSU

The Ocean’s Deepest Point

The deepest point in the ocean is the Mariana Trench, at 11,034 meters (36,201 feet).

This trench is located in the Pacific Ocean, near Guam and the trench’s namesake, the Mariana Islands. While the trench is the most extreme example of ocean depths, when compared to surface level distance, it’s depth is shorter than Manhattan.

Mariana trench depth compared to cities

Obviously, the context of surface distance is wildly different than vertical distance, but it serves as a reminder of how narrow the “explorable” band of the Earth’s surface is.

Polymetallic Nodules

The ancient Greek word, ábyssos, roughly means “unfathomable, bottomless gulf”. While there is a bottom (the abyssopelagic zone comprises around 75% of the ocean floor), the enormous scale of this ecosystem is certainly unfathomable.

Objectively, the abyssal plain is not the prettiest part of the ocean. It’s nearly featureless, and lacks the panache of, say, a coral reef, but there are still some very compelling reasons we’re eager to explore it. Resource companies are chiefly interested in polymetallic nodules, which are essentially rich manganese formations scattered about on the sea bottom.

Manganese is already essential in steel production, but demand is also getting a substantial lift from the fast-growing electric vehicle market. The first company to find an economical way to harvest nodules from the ocean floor could reap a significant windfall.

Drill Baby, Drill

Demand for resources can force humans into some very inhospitable places, and in the case of Deepwater Horizon, we chased oil to a depth even surpassing the famed Marianas Trench.

Drilling that far below the surface is a complicated endeavor, and when the drill platform was put into service in 2001, it was hailed as an engineering marvel. To this day, Deepwater Horizon holds the record for the deepest offshore hole ever made.

After the rig’s infamous explosion and subsequent spill in 2010, that depth record for drilling may stand the test of time.

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