As the Worlds Turn: Visualizing the Rotations of Planets
The rotation of planets have a dramatic effect on their potential habitability.
Dr. James O’Donoghue, a planetary scientist at the Japanese space agency who has the creative ability to visually communicate space concepts like the speed of light and the vastness of the solar system, recently animated a video showing cross sections of different planets spinning at their own pace on one giant globe.
Cosmic Moves: The Rotation of the Planets
Each planet in the solar system moves to its own rhythm. The giant gas planets (Jupiter, Saturn, Uranus, and Neptune) spin more rapidly on their axes than the inner planets. The sun itself rotates slowly, only once a month.
|Planet||Rotation Periods (relative to stars)|
The planets all revolve around the sun in the same direction and in virtually the same plane. In addition, they all rotate in the same general direction, with the exceptions of Venus and Uranus.
In the following animation, their respective rotation speeds are compared directly:
The most visually striking result of planetary spin is on Jupiter, which has the fastest rotation in the solar system. Massive storms of frozen ammonia grains whip across the surface of the gas giant at speeds of 340 miles (550 km) per hour.
Interestingly, the patterns of each planet’s rotation can help in revealing whether they can support life or not.
Rotation and Habitability
As a fish in water is not aware it is wet, so it goes for humans and the atmosphere around us.
New research reveals that the rate at which a planet spins is an essential component for supporting life. Not only does rotation control the length of day and night, bit it influences atmospheric wind patterns and the formation of clouds.
The radiation the Earth receives from the Sun concentrates at the equator. The Sun heats the air in this region until it rises up through the atmosphere and moves towards the poles of the planet where it cools. This cool air falls through the atmosphere and flows back towards the equator.
This process is known as a Hadley cell, and atmospheres can have multiple cells:
A planet with a quick rotation forms Hadley cells at low latitudes into different bands that encircle the planet. Clouds become prominent at tropical regions, which reflect a proportion of the light back into space.
For a planet in a tighter orbit around its star, the radiation received from the star is much more extreme. This decreases the temperature difference between the equator and the poles, ultimately weakening Hadley cells. The result is fewer clouds in tropical regions available to protect the planet from intense heat, making the planet uninhabitable.
Slow Rotators: More Habitable
If a planet rotates slower, then the Hadley cells can expand to encircle the entire world. This is because the difference in temperature between the day and night side of the planet creates larger atmospheric circulation.
Slow rotation makes days and nights longer, such that half of the planet bathes in light from the sun for an extended period of time. Simultaneously, the night side of the planet is able to cool down.
This difference in temperature is large enough to cause the warm air from the day side to flow to the night side. This movement of air allows more clouds to form around a planet’s equator, protecting the surface from harmful space radiation, encouraging the possibility for the right conditions for life to form.
The Hunt for Habitable Planets
Measuring the rotation of planets is difficult with a telescope, so another good proxy would be to measure the level of heat emitted from a planet.
An infrared telescope can measure the heat emitted from a planet’s clouds that formed over its equator. An unusually low temperature at the hottest location on the planet could indicate that the planet is potentially a habitable slow rotator.
Of course, even if a planet’s rotation speed is just right, many other conditions come into play. The rotation of planets is just another piece in the puzzle in identifying the next Earth.
Mapped: Second Primary Languages Around the World
This fascinating map highlights the second most commonly spoken primary language in almost nearly every country.
Mapped: Second Primary Languages Around the World
After the primary language, what second languages are used as native tongues in your country?
The answer reveals a lot about history and location. Whether through immigration, colonization, or local culture, a primary language can either spread around the world or remain rooted in place.
This map from MoveHub shows the second most commonly spoken primary language in most countries, using data from the CIA World Factbook and Wikipedia as of February 2021.
The Difference Between Primary and Secondary Languages
First, it’s important to differentiate between primary languages and secondary languages.
A primary language—also known as a first or native language—is the language we use most frequently to communicate. These are languages we are usually born with, have a lot of exposure to, and use at home.
On the other hand, a secondary language is one we learn or pick up after our primary language. In many countries, English is the most commonly learned, with close to 1 billion speakers.
But a map of common second languages can simply show just how many countries prioritize learning English, the de-facto international language in many organizations. Instead, this map highlights the movement of people by showing the second-most common primary language.
The Second Most Common Primary Languages by Country
Even when filtering by primary language use, however, English and other Indo-European languages dominate the world.
With 55 countries speaking it as the second-most common primary language, English came out on top.
|Top 10 Most Popular Second Primary Languages||Number of Countries|
The use of English as a second primary language was primarily concentrated in Western Europe, Northern Africa, and Southeast Asia and Oceania.
Similarly to second-place French with 14 countries and third-place Russian with 13 countries, English was most common in proximity to English-speaking countries or where there was a history of immigration.
Other second-most common primary languages highlighted different cultures within countries, such as China’s second-most common language Cantonese. Alternatively, they showed the primary indigenous language before colonization, such as the Quechua languages in South America.
What other interesting or surprising language patterns can you spot in the map above?
Mapped: Human Impact on the Earth’s Surface
This detailed map looks at where humans have (and haven’t) modified Earth’s terrestrial environment. See human impact in incredible detail.
Mapped: Human Impact on the Earth’s Surface
With human population on Earth approaching 8 billion (we’ll likely hit that milestone in 2023), our impact on the planet is becoming harder to ignore with each passing year.
Our cities, infrastructure, agriculture, and pollution are all forms of stress we place on the natural world. This map, by David M. Theobald et al., shows just how much of the planet we’ve now modified. The researchers estimate that 14.6% or 18.5 million km² of land area has been modified – an area greater than Russia.
Defining Human Impact
Human impact on the Earth’s surface can take a number of different forms, and researchers took a nuanced approach to classifying the “modifications” we’ve made. In the end, 10 main stressors were used to create this map:
- Built-Up Areas: All of our cities and towns
- Agriculture: Areas devoted to crops and pastures
- Energy and extractive resources: Primarily locations where oil and gas are extracted
- Mines and quarries: Other ground-based natural resource extraction, excluding oil and gas
- Power plants: Areas where energy is produced – both renewable and non-renewable
- Transportation and service corridors: Primarily roads and railways
- Logging: This measures commodity-based forest loss (excludes factors like wildfire and urbanization)
- Human intrusion: Typically areas adjacent to population centers and roads that humans access
- Natural systems modification: Primarily modifications to water flow, including reservoir creation
- Pollution: Phenomenon such as acid rain and fog caused by air pollution
The classification descriptions above are simplified. See the methodology for full descriptions and calculations.
A Closer Look at Human Impact on the Earth’s Surface
To help better understand the level of impact humans can have on the planet, we’ll take a closer look three regions, and see how the situation on the ground relates to these maps.
Land Use Contrasts: Egypt
Almost all of Egypt’s population lives along the Nile and its delta, making it an interesting place to examine land use and human impact.
The towns and high intensity agricultural land following the river stand out clearly on the human modification map, while the nearby desert shows much less impact.
Intensive Modification: Netherlands
The Netherlands has some of the heavily modified landscapes on Earth, so the way it looks on this map will come as no surprise.
The area shown above, Rotterdam’s distinctive port and surround area, renders almost entirely in colors at the top of the human modification scale.
Resource Extraction: West Virginia
It isn’t just cities and towns that show up clearly on this map, it’s also the areas we extract our raw materials from as well. This mountainous region of West Virginia, in the United States, offers a very clear visual example.
The mountaintop removal method of mining—which involves blasting mountains in order to retrieve seams of bituminous coal—is common in this region, and mine sites show up clearly in the map.
You can explore the interactive version of this map yourself to view any area on the globe. What surprises you about these patterns of human impact?
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