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Visualizing the History of Pandemics

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The History of Pandemics by Death Toll

The History of Pandemics

Pan·dem·ic /panˈdemik/ (of a disease) prevalent over a whole country or the world.

As humans have spread across the world, so have infectious diseases. Even in this modern era, outbreaks are nearly constant, though not every outbreak reaches pandemic level as COVID-19 has.

Today’s visualization outlines some of history’s most deadly pandemics, from the Antonine Plague to the current COVID-19 event.

A Timeline of Historical Pandemics

Disease and illnesses have plagued humanity since the earliest days, our mortal flaw. However, it was not until the marked shift to agrarian communities that the scale and spread of these diseases increased dramatically.

Widespread trade created new opportunities for human and animal interactions that sped up such epidemics. Malaria, tuberculosis, leprosy, influenza, smallpox, and others first appeared during these early years.

The more civilized humans became – with larger cities, more exotic trade routes, and increased contact with different populations of people, animals, and ecosystems – the more likely pandemics would occur.

Here are some of the major pandemics that have occurred over time:

NameTime periodType / Pre-human hostDeath toll
Antonine Plague165-180Believed to be either smallpox or measles5M
Japanese smallpox epidemic735-737Variola major virus1M
Plague of Justinian541-542Yersinia pestis bacteria / Rats, fleas30-50M
Black Death1347-1351Yersinia pestis bacteria / Rats, fleas200M
New World Smallpox Outbreak1520 – onwardsVariola major virus56M
Great Plague of London1665Yersinia pestis bacteria / Rats, fleas100,000
Italian plague1629-1631Yersinia pestis bacteria / Rats, fleas1M
Cholera Pandemics 1-61817-1923V. cholerae bacteria1M+
Third Plague1885Yersinia pestis bacteria / Rats, fleas12M (China and India)
Yellow FeverLate 1800sVirus / Mosquitoes100,000-150,000 (U.S.)
Russian Flu1889-1890Believed to be H2N2 (avian origin)1M
Spanish Flu1918-1919H1N1 virus / Pigs40-50M
Asian Flu1957-1958H2N2 virus1.1M
Hong Kong Flu1968-1970H3N2 virus1M
HIV/AIDS1981-presentVirus / Chimpanzees25-35M
Swine Flu2009-2010H1N1 virus / Pigs200,000
SARS2002-2003Coronavirus / Bats, Civets770
Ebola2014-2016Ebolavirus / Wild animals11,000
MERS2015-PresentCoronavirus / Bats, camels850
COVID-192019-PresentCoronavirus – Unknown (possibly pangolins)502.7K (Johns Hopkins University estimate as of 8:33am PT, June 29, 2020)

Note: Many of the death toll numbers listed above are best estimates based on available research. Some, such as the Plague of Justinian and Swine Flu, are subject to debate based on new evidence.

Despite the persistence of disease and pandemics throughout history, there’s one consistent trend over time – a gradual reduction in the death rate. Healthcare improvements and understanding the factors that incubate pandemics have been powerful tools in mitigating their impact.

Wrath of the Gods

In many ancient societies, people believed that spirits and gods inflicted disease and destruction upon those that deserved their wrath. This unscientific perception often led to disastrous responses that resulted in the deaths of thousands, if not millions.

In the case of Justinian’s plague, the Byzantine historian Procopius of Caesarea traced the origins of the plague (the Yersinia pestis bacteria) to China and northeast India, via land and sea trade routes to Egypt where it entered the Byzantine Empire through Mediterranean ports.

Despite his apparent knowledge of the role geography and trade played in this spread, Procopius laid blame for the outbreak on the Emperor Justinian, declaring him to be either a devil, or invoking God’s punishment for his evil ways. Some historians found that this event could have dashed Emperor Justinian’s efforts to reunite the Western and Eastern remnants of the Roman Empire, and marked the beginning of the Dark Ages.

Luckily, humanity’s understanding of the causes of disease has improved, and this is resulting in a drastic improvement in the response to modern pandemics, albeit slow and incomplete.

Importing Disease

The practice of quarantine began during the 14th century, in an effort to protect coastal cities from plague epidemics. Cautious port authorities required ships arriving in Venice from infected ports to sit at anchor for 40 days before landing — the origin of the word quarantine from the Italian “quaranta giorni”, or 40 days.

One of the first instances of relying on geography and statistical analysis was in mid-19th century London, during a cholera outbreak. In 1854, Dr. John Snow came to the conclusion that cholera was spreading via tainted water and decided to display neighborhood mortality data directly on a map. This method revealed a cluster of cases around a specific pump from which people were drawing their water from.

While the interactions created through trade and urban life play a pivotal role, it is also the virulent nature of particular diseases that indicate the trajectory of a pandemic.

Tracking Infectiousness

Scientists use a basic measure to track the infectiousness of a disease called the reproduction number — also known as R0 or “R naught.” This number tells us how many susceptible people, on average, each sick person will in turn infect.

Measles tops the list, being the most contagious with a R0 range of 12-18. This means a single person can infect, on average, 12 to 18 people in an unvaccinated population.

While measles may be the most virulent, vaccination efforts and herd immunity can curb its spread. The more people are immune to a disease, the less likely it is to proliferate, making vaccinations critical to prevent the resurgence of known and treatable diseases.

It’s hard to calculate and forecast the true impact of COVID-19, as the outbreak is still ongoing and researchers are still learning about this new form of coronavirus.

Urbanization and the Spread of Disease

We arrive at where we began, with rising global connections and interactions as a driving force behind pandemics. From small hunting and gathering tribes to the metropolis, humanity’s reliance on one another has also sparked opportunities for disease to spread.

Urbanization in the developing world is bringing more and more rural residents into denser neighborhoods, while population increases are putting greater pressure on the environment. At the same time, passenger air traffic nearly doubled in the past decade. These macro trends are having a profound impact on the spread of infectious disease.

As organizations and governments around the world ask for citizens to practice social distancing to help reduce the rate of infection, the digital world is allowing people to maintain connections and commerce like never before.

Editor’s Note: The COVID-19 pandemic is in its early stages and it is obviously impossible to predict its future impact. This post and infographic are meant to provide historical context, and we will continue to update it as time goes on to maintain its accuracy.

Update (March 15, 2020): We’ve adjusted the death toll for COVID-19, and will continue to update on a regular basis.

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Misc

The 44 Closest Stars and How They Compare to our Sun

This graphic visualizes the 44 closest stars, revealing key facts such as distance from Earth, brightness, and whether potential planets are in orbit.

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44 closest stars

44 Closest Stars and How They Compare to our Sun

Humans have been fascinated by the stars in the night sky since the dawn of time.

We’ve been decoding the mysteries of celestial bodies for many centuries, but it is only in the last 200 years or so that we’ve been able to glean more detailed information on the lights that dot the night sky. Friedrich Bessel’s method of stellar parallax was a breakthrough in accurately measuring the positions of stars, and opened new doors in the effort to map our universe. Today, high-powered telescopes offer even more granular data on our cosmic neighborhood.

The infographic above, from Alan’s Factory Outlet, categorizes the 44 closest stars to Earth, examining the size, luminosity, constellations, systems, and potential planets of each star.

Our Nearest Stellar Neighbors

Our closest neighboring stars are all part of the same solar system: Alpha Centauri. This triple star system – consisting of Proxima Centauri, Alpha Centauri A, and Alpha Centauri B – attracts a lot of interest because it hosts planets, including one that may be similar to Earth.

The planet, Proxima Centauri b, is a lot closer to its star than Earth is to the Sun. However, because Proxima Centauri is a smaller and cooler red dwarf type star, the planet’s orbit is within the habitable zone. It’s thought that Proxima Centauri b receives approximately the same amount of solar energy as Earth does from our Sun.

Here’s a full list of the 44 of the closest stars to Earth:

Star NameDistance (light years)MoE
Sun0.000016±0.0011
Proxima Centauri4.37±0.0068
α Centauri A4.37±0.0068
α Centauri B4.37±0.0068
Barnard's Star5.96±0.0032
Wolf 3597.86±0.031
Lalande 211858.31±0.014
Sirius A8.66±0.010
Sirius B8.66±0.010
Luyten 726-8 A8.79±0.012
Luyten 726-8 B8.79±0.012
Ross 1549.70±0.0019
Ross 24810.29±0.0041
Epsilon Eridani10.45±0.016
Lacaille 935210.72±0.0016
Ross 12811.01±0.0026
EZ Aquarii A11.11±0.034
61 Cygni A11.40±0.0012
61 Cygni B11.40±0.0012
Procyon A11.40±0.032
Procyon B11.40±0.032
Struve 2398 A11.49±0.0012
Struve 2398 B11.49±0.0012
Groombridge 34 A11.62±0.0008
Groombridge 34 B11.62±0.0008
DX Cancri11.68±0.0056
Tau Ceti11.75±0.022
Epsilon Indi11.87±0.011
Gliese 106111.98±0.0029
YZ Ceti12.11±0.0035
Luyten's Star12.20±0.036
Teegarden's Star12.50±0.013
SCR 1845-635713.05±0.008
Kapteyn's Star12.83±0.0013
Lacaille 876012.95±0.0029
Kruger 60 A13.07±0.0052
Kruger 60 B13.07±0.0052
Wolf 106114.05±0.0038
Wolf 424 A14.05±0.26
Van Maanen's star14.07±0.0023
Gliese 114.17±0.0037
TZ Arietis14.58±0.0070
Gliese 67414.84±0.0033
Gliese 68714.84±0.0022

Even though we see many of these stars in the night sky, humans aren’t likely to see them in person any time soon. To put these vast distances into perspective, if the Voyager spacecraft were to travel to Proxima Centauri, it would take over 73,000 years to finally arrive.

The Brightest Stars in the Sky

The closest stars aren’t necessarily the ones most visible to us here on Earth. Here are the top 10 stars in terms of visual brightness from Earth:

RankProper nameConstellationVisual magnitude (mV)Distance (light years)
1SunN/A−26.740.000016
2SiriusCanis Major−1.468.6
3CanopusCarina−0.74310.0
4Rigil Kentaurus & TolimanCentaurus−0.27 (0.01 + 1.33)4.4
5ArcturusBoötes−0.0537.0
6VegaLyra0.03 (−0.02–0.07var)25.0
7CapellaAuriga0.08 (0.03–0.16var)43.0
8RigelOrion0.13 (0.05–0.18var)860.0
9ProcyonCanis Minor0.3411.0
10AchernarEridanus0.46 (0.40–0.46var)139.0

Excluding our Sun, the brightest star visible from Earth is Sirius, or the Dog Star. Sirius, which is about 25 times more luminous than the sun, visually punctuates the constellation Canis Major.

Filling in the Gaps

The next step in learning more about our surroundings in the cosmos will be seeing which of the stars listed above have planets orbiting them. So far, the 44 stars in the infographic have over 40 planets scattered among them, though new discoveries are made all the time.

With each new mission and discovery, we learn a little bit more about our pocket of the universe.

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Politics

Visualizing the True Size of Land Masses from Largest to Smallest

Maps can distort the size and shape of countries. This visualization puts the true size of land masses together from biggest to smallest.

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The True Size of Land Masses from Largest to Smallest

Is Greenland the size of the entire African continent?

No…

But looking at a map based on the Mercator projection, you would think so.

Today’s infographic comes from the design studio Art.Lebedev and shows the true size of the world’s land masses in order from largest to smallest using data from NASA and Google.

Check out the actual shape and size of each land mass without any distortions.

Distorting Reality: Mercator Misconceptions

Maps can deceive your eyes but they are still powerful tools for specific purposes. In 1569, the legendary cartographer, Gerardus Mercator, created a new map based on a cylindrical projection of sections of the Earth. These types of maps were suited for nautical navigation since every line on the sphere is a constant course, or loxodrome.

Despite the map’s nautical utility, the Mercator projection has an unwanted downside. The map type increases the sizes of land masses close to the poles (such as in North America, Europe, or North Asia) as a side effect. As a result, Canada and Russia appear to take up approximately 25% of the Earth’s surface, when in reality these nations only occupy 5%.

“Things are not always what they seem; the first appearance deceives many.” – Phaedrus

This collection of images above represents the world’s land masses in their correct proportions. Measurements are based on Google Maps 2016 and NASA Earth Observatory maps, with calculations based on the WGS84 reference ellipsoid, or more simply, a specific model of the Earth’s shape in two dimensions.

We take for granted Google Maps and satellite imaging. Making these accurate representations is no small task – the designers went through six steps and many different iterations of the graphic.

Countries are arranged by descending size and shown without external or dependent territories. For example, the total area for the contiguous United States shown does not include Hawaii, Alaska, or overseas territories.

Top 10 Largest Land Masses

Although Mercator maps distort the size of land masses in the Northern Hemisphere, many of these countries still cover massive territories.

JurisdictionArea (km²)
Russia16,440,626
Antarctica12,269,609
China9,258,246
Canada8,908,366
Brazil8,399,858
United States (contiguous)7,654,643
Australia7,602,329
India3,103,770
Argentina2,712,060
Kazakhstan2,653,464

The top 10 land masses by size account for 55% of the Earth’s total land. The remainder is split by the world’s 195 or so other countries.

Top 10 Smallest Land Masses

Here are the 10 tiniest jurisdictions highlighted on the map:

JurisdictionArea (km²)
Sealand0.001
Kingman Reef0.002
Vatican City0.5
Kure Atoll0.9
Tromelin Island1
Johnston Atoll1
Baker Island1
Howland Island2
Monaco2
Palmyra Atoll3

While the Earth’s land surface has been claimed by many authorities, the actual impact of human activity is less than one would think.

Human Impact: Humbled by Nature

Political borders have claimed virtually every piece of land available. Despite this, only 20% of land on the planet has been visibly impacted by human activity, and only 15% of Earth’s land surface is formally under protection.

The remaining 80% of the land hosts natural ecosystems that help to purify air and water, recycle nutrients, enhance soil fertility, pollinate plants, and break down waste products. The value of maintaining these services to the human economy is worth trillions of U.S. dollars each year.

While some nations are not as big as they look on the map, every piece of land counts.

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