The darkest days are upon the residents of the Northern Hemisphere as daylight dwindles and the night lingers longer. Meanwhile, those in the Southern Hemisphere bask in their warmest and longest days—and those at the Equator continue to observe consistent days and nights.
These changing lengths of days and nights depend on where you are on Earth and the time of year. The tilt of the Earth’s axis and its path around the sun affect the number of daylight hours.
Today’s post highlights two simple and elegant animations that help demonstrate how different latitudes experience the sun’s light over the course of one year. The first comes from Reddit user harplass, while the second comes from data scientist Neil Kaye.
Longer and Shorter Days
The Ancient Greeks envisioned the movement of the sun as a Titan named Helios who rode across the sky in a horse-drawn chariot, illuminating the known world below. A rosy-fingered dawn would herald his imminent arrival, while the arrival of the dusk god Astraeus, ever on Helios’ heels, marked the passage of day into night.
Today, time is not at the whims of Greek mythology but by the measurable and consistent movement of celestial bodies. A day on Earth is 24 hours long, but not every day has 12 hours of daylight and 12 hours of night. The actual time of one Earth rotation is a little shorter–about 23 hours and 56 minutes.
Daytime is shorter in winter than in summer, for each hemisphere. This is because the Earth’s imaginary axis isn’t straight up and down, it is tilted 23.5 degrees. The Earth’s movement around this axis causes the change between day and night.
During summer in the Northern Hemisphere, daylight hours increase the farther north you go. The Arctic gets very little darkness at night. The seasonal changes in daylight hours are small near the Equator and more extreme close to the poles.
Length of a Rotation: Equinoxes and Solstices
There are four events that mark the passing stages of the sun, equinoxes and solstices.
The two solstices happen June 20 or 21 and December 21 or 22. These are the days when the sun’s path in the sky is the farthest north or south from the Equator. A hemisphere’s winter solstice is the shortest day of the year and the summer solstice the year’s longest.
In the Northern Hemisphere the June solstice marks the start of summer: this is when the North Pole is tilted closest to the sun, and the sun’s rays are directly overhead at the Tropic of Cancer.
The December solstice marks the start of winter when the South Pole is tilted closest to the sun, and the sun’s rays are directly overhead the Tropic of Capricorn.
The equinoxes happen around March 21 and September 23. These are the days when the sun is exactly above the Equator, which makes day and night of equal length.
Stand in the Place Where You Are
It is always darkest before the dawn, and every passing of solstice marks a time of change. As the Northern Hemisphere heads into the winter holiday season, it also marks the advent of longer days and the inevitable spring and summer.
The lengths of days and nights are constantly changing, but every one will get their time in the sun, at some point.
Visualizing China’s Dominance in Battery Manufacturing (2022-2027P)
This infographic breaks down battery manufacturing capacity by country in 2022 and 2027.
Visualizing China’s Dominance in Battery Manufacturing
With the world gearing up for the electric vehicle era, battery manufacturing has become a priority for many nations, including the United States.
However, having entered the race for batteries early, China is far and away in the lead.
Using the data and projections behind BloombergNEF’s lithium-ion supply chain rankings, this infographic visualizes battery manufacturing capacity by country in 2022 and 2027p, highlighting the extent of China’s battery dominance.
Battery Manufacturing Capacity by Country in 2022
In 2022, China had more battery production capacity than the rest of the world combined.
|Rank||Country||2022 Battery Cell|
Manufacturing Capacity, GWh
|% of Total|
|#7||🇰🇷 South Korea||15||1%|
With nearly 900 gigawatt-hours of manufacturing capacity or 77% of the global total, China is home to six of the world’s 10 biggest battery makers. Behind China’s battery dominance is its vertical integration across the rest of the EV supply chain, from mining the metals to producing the EVs. It’s also the largest EV market, accounting for 52% of global sales in 2021.
Poland ranks second with less than one-tenth of China’s capacity. In addition, it hosts LG Energy Solution’s Wroclaw gigafactory, the largest of its kind in Europe and one of the largest in the world. Overall, European countries (including non-EU members) made up just 14% of global battery manufacturing capacity in 2022.
Although it lives in China’s shadow when it comes to batteries, the U.S. is also among the world’s lithium-ion powerhouses. As of 2022, it had eight major operational battery factories, concentrated in the Midwest and the South.
China’s Near-Monopoly Continues Through 2027
Global lithium-ion manufacturing capacity is projected to increase eightfold in the next five years. Here are the top 10 countries by projected battery production capacity in 2027:
|Rank||Country||2027P Battery Cell|
Manufacturing Capacity, GWh
|% of Total|
China’s well-established advantage is set to continue through 2027, with 69% of the world’s battery manufacturing capacity.
Meanwhile, the U.S. is projected to increase its capacity by more than 10-fold in the next five years. EV tax credits in the Inflation Reduction Act are likely to incentivize battery manufacturing by rewarding EVs made with domestic materials. Alongside Ford and General Motors, Asian companies including Toyota, SK Innovation, and LG Energy Solution have all announced investments in U.S. battery manufacturing in recent months.
Europe will host six of the projected top 10 countries for battery production in 2027. Europe’s current and future battery plants come from a mix of domestic and foreign firms, including Germany’s Volkswagen, China’s CATL, and South Korea’s SK Innovation.
Can Countries Cut Ties With China?
Regardless of the growth in North America and Europe, China’s dominance is unmatched.
Battery manufacturing is just one piece of the puzzle, albeit a major one. Most of the parts and metals that make up a battery—like battery-grade lithium, electrolytes, separators, cathodes, and anodes—are primarily made in China.
Therefore, combating China’s dominance will be expensive. According to Bloomberg, the U.S. and Europe will have to invest $87 billion and $102 billion, respectively, to meet domestic battery demand with fully local supply chains by 2030.
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