The Knowledge
Why can’t it always be summer? It’s all about the Earth’s tilt
Earth’s axial tilt causes the seasons. As Earth orbits the Sun, different hemispheres tilt toward or away, creating summer and winter depending on location.
Last Updated on March 13, 2026 by Daily News Staff
Stephanie Spera, University of Richmond
Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.
Why can’t it always be summer? – Amanda, age 5, Chile
With its long days just itching to be spent by water doing nothing, summer really can be an enchanting season. As Jenny Han wrote in the young adult novel “The Summer I Turned Pretty”: “Everything good, everything magical happens between the months of June and August.”
But all good things must come to an end, and summer cannot last forever. There’s both a simple reason and a more complicated one. The simple reason is that it can’t always be summer because the Earth is tilted. The more complicated answer requires some geometry.
I’m a professor of geography and the environment who has studied seasonal changes on the landscape. Here’s what seasons have to do with our planet’s position as it moves through the solar system.
This animation shows why the Earth has seasons.
Closeness to the Sun doesn’t explain seasons
First, you need to know that the Earth is a sphere – technically, an oblate spheroid. That means Earth has a round shape a little wider than it is tall.
Every year, Earth travels in its orbit to make one revolution around the Sun. The Earth’s orbit is an ellipse, which is more like an oval than a circle. So there are times when Earth is closer to the Sun and times when it’s farther away.
A lot of people assume this distance is why we have seasons. But these people would be wrong. In the United States, the Earth is 3 million miles closer to the Sun during winter than in the summer.
Spinning like a top
Now picture an imaginary line across Earth, right in the middle, at 0° latitude. This line is called the equator. If you drew it on a globe, the equator would pass through countries including Brazil, Kenya, Indonesia and Ecuador.
Everything north of the equator, including the United States, is considered the Northern Hemisphere, and everything south of the equator is the Southern Hemisphere.
Now think of the Earth’s axis as another imaginary line that runs vertically through the middle of the Earth, going from the North Pole to the South Pole.
As it orbits, or revolves, around the Sun, the Earth also rotates. That means it spins on its axis, like a top. The Earth takes one full year to revolve around the Sun and takes 24 hours, or one day, to do one full rotation on its axis.
This axis is why we have day and night; during the day, we’re facing the Sun, and at night, we’re facing away.
But the Earth’s axis does not go directly up and down. Instead, its axis is always tilted at 23.5 degrees in the exact same direction, toward the North Star.
The Earth’s axis is tilted due to a giant object – perhaps an ancient planet – smashing into it billions of years ago. And it’s this tilt that causes seasons.
It’s all about the tilt
So that means in June, the Northern Hemisphere is tilted toward the Sun. That tilt means more sunlight, more solar energy, longer days – all the things that make summer, well, summer.
At the same time, the Southern Hemisphere is tilted away from the Sun. So countries such as Australia, Chile and Argentina are experiencing winter then.
To say it another way: As the Earth moves around the Sun throughout the year, the parts of the Earth getting the most sunlight are always changing.
Fast-forward to December, and Earth is on the exact opposite side of its orbit as where it was in June. It’s the Southern Hemisphere’s turn to be tilted toward the Sun, which means its summer happens in December, January and February.
If Earth were not tilted at all, there would be no seasons. If it were tilted more than it is, there would be even more extreme seasons and drastic swings in temperature. Summers would be hotter and winters would be colder.
Defining summer
Talk to a meteorologist, climate scientist or author Jenny Han, and they’ll tell you that for those of us in the Northern Hemisphere, summer is June, July and August, the warmest months of the year.
But there’s another way to define summer. Talk to astronomers, and they’ll tell you the first day of summer is the summer solstice – the day of the year with the longest amount of daylight and shortest amount of darkness.
The summer solstice occurs every year sometime between June 20 and June 22. And every day after, until the winter solstice in December, the Northern Hemisphere receives a little less daylight.
Summer officially ends on the autumnal equinox, the fall day when everywhere on Earth has an equal amount of daylight and night. The autumnal equinox happens every year on either September 22 or 23.
But whether you view summer like Jenny Han or like an astronomer, one thing is certain: Either way, summer must come to an end. But the season and the magic it brings with it will be back before you know it.
Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.
And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.
Stephanie Spera, Assistant Professor of Geography and the Environment, University of Richmond
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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The Knowledge
Forgotten Genius Fridays: Madison Washington and the Slave Revolt That Changed History
Discover the inspiring story of Madison Washington, the courageous freedom fighter who led the 1841 Creole revolt, securing freedom for 128 enslaved people in the most successful slave uprising in American history.
When people think of heroic figures who fought against slavery, names like Harriet Tubman, Frederick Douglass, and Sojourner Truth often come to mind. Yet one remarkable man remains largely absent from history books despite leading the most successful slave revolt in American history.
His name was Madison Washington.
His courage aboard the brig Creole in 1841 transformed the lives of more than one hundred enslaved people and became a powerful symbol of the fight for freedom.
Born Into Slavery
Madison Washington was born into slavery in Virginia during the early 19th century. Like millions of enslaved African Americans, he endured the brutality and injustice of a system that denied him even the most basic human rights.
Determined to be free, Washington escaped slavery in 1839 and reached Canada with help from the Underground Railroad.
Freedom, however, came with heartbreak.
His wife remained enslaved in Virginia, and Washington made the extraordinary decision to risk everything by returning to rescue her.
Instead, he was captured and imprisoned.
The Voyage Aboard the Creole
In November 1841, Washington and 134 other enslaved people were forced aboard the American slave ship Creole. The vessel was headed from Virginia to New Orleans, where many of the captives would likely be sold to plantations across the Deep South.
Washington refused to accept that fate.
On November 7, he and several fellow captives launched a carefully planned revolt. During the struggle, one slave trader was killed, while much of the crew was subdued.
Rather than continue to New Orleans, Washington ordered the crew to sail to Nassau in the Bahamas.
Freedom in the Bahamas
The decision proved historic.
Great Britain had abolished slavery throughout most of its empire years earlier, and when the Creole arrived in Nassau, British authorities refused American demands to return the enslaved passengers as property.
Instead, 128 formerly enslaved people were granted their freedom.
The Creole revolt became the most successful slave uprising in United States history.
International Consequences
The incident sparked a diplomatic dispute between the United States and Great Britain that lasted for years.
Southern slaveholders demanded compensation for what they viewed as lost property, while abolitionists celebrated Madison Washington as a courageous freedom fighter who challenged one of history’s greatest injustices.
The event also strengthened arguments against slavery by demonstrating that people held in bondage would continue to resist oppression whenever opportunities arose.
Frederick Douglass Honors a Hero
Madison Washington’s bravery inspired one of America’s greatest abolitionists.
Frederick Douglass based his 1853 novella, The Heroic Slave, on Washington’s remarkable story. The work became one of the earliest pieces of African American fiction centered on a real historical figure and introduced many readers to Washington’s extraordinary leadership.
Although historical records about Washington’s later life remain scarce, his legacy lived on through Douglass’s writing and through the generations of freedom seekers who followed.
Why Madison Washington Matters Today
Madison Washington reminds us that history is filled with individuals whose contributions have been overlooked despite changing the course of events.
His story is about more than a shipboard revolt.
It is about courage in the face of impossible odds.
It is about sacrificing personal safety for loved ones.
And it is about the universal desire for freedom.
As we continue to uncover stories that have too often been left untold, Madison Washington deserves recognition alongside the great heroes of American history.
His determination helped secure freedom for more than one hundred people—and his legacy continues to inspire those who believe that justice is always worth fighting for.
Forgotten Genius Fridays
Every Friday, STM Daily News shines a light on remarkable people whose contributions have shaped our world but whose stories deserve greater recognition. Join us as we rediscover the innovators, pioneers, leaders, and trailblazers history should never forget.
What other forgotten heroes should we feature next? Share your suggestions in the comments, and don’t forget to subscribe to the STM Daily News newsletter for more inspiring stories delivered straight to your inbox.
Related External Links
For readers interested in learning more about Madison Washington, the Creole revolt, and the broader history of slavery and abolition, these trusted resources provide additional historical context:
- Library of Congress – Frederick Douglass Papers: https://www.loc.gov/collections/frederick-douglass-papers/
- National Park Service – Underground Railroad: https://www.nps.gov/subjects/undergroundrailroad/index.htm
- Smithsonian National Museum of African American History and Culture: https://nmaahc.si.edu/
- National Archives – African American History: https://www.archives.gov/research/african-americans
- Encyclopaedia Britannica – Creole Revolt: https://www.britannica.com/event/Creole-slave-revolt
- Encyclopaedia Britannica – Frederick Douglass: https://www.britannica.com/biography/Frederick-Douglass
- Library of Congress – Slavery and the Struggle for Freedom: https://www.loc.gov/classroom-materials/slavery-and-the-struggle-for-freedom/
Note: External links are provided for educational and informational purposes. STM Daily News is not responsible for the content or policies of third-party websites.
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Forgotten Genius Fridays
Katherine Johnson: The Human Computer Who Helped America Reach the Moon
Discover how Katherine Johnson’s mathematical genius helped NASA send astronauts into space and to the Moon. Learn why she remains one of America’s most inspiring scientific pioneers.
Forgotten Genius Friday | The Knowledge | STM Daily News
When the United States raced to explore space during the 1950s and 1960s, rockets and astronauts often captured the headlines. Behind every successful mission, however, was a team of brilliant mathematicians and engineers whose calculations made spaceflight possible. Among them was Katherine Johnson, an extraordinary mathematician whose work helped America reach orbit, the Moon, and beyond.
Although her contributions remained largely unknown for decades, Katherine Johnson’s remarkable career transformed the U.S. space program and inspired generations of scientists, engineers, and mathematicians.
A Gift for Mathematics
Katherine Coleman Goble Johnson was born on August 26, 1918, in White Sulphur Springs, West Virginia. From an early age, her exceptional talent for mathematics was evident. She skipped several grades, graduated from high school at just 14 years old, and earned degrees in mathematics and French from West Virginia State College by the age of 18.
At a time when educational and career opportunities for African American women were limited, Johnson’s determination and love of mathematics helped her overcome barriers that stood in the way of many aspiring scientists.
Joining America’s Space Program
In 1953, Johnson joined the National Advisory Committee for Aeronautics (NACA), the agency that would later become NASA.
She worked in the segregated West Area Computing Unit, where African American women served as “human computers,” performing complex mathematical calculations by hand. Their work was essential to aircraft research and, later, the nation’s ambitious efforts in human spaceflight.
Johnson’s exceptional analytical skills quickly earned the respect of engineers and mission planners. Rather than simply solving equations, she asked questions, challenged assumptions, and helped develop solutions to problems that had never been encountered before.
The Woman John Glenn Trusted
One of Katherine Johnson’s most famous moments came in 1962 before astronaut John Glenn became the first American to orbit Earth.
NASA had begun using electronic computers to calculate flight trajectories, but Glenn wanted one final verification before launch. According to NASA’s historical accounts, he requested that Katherine Johnson personally check the computer’s calculations.
“If she says they’re good,” Glenn reportedly said, “then I’m ready to go.”
Johnson confirmed the numbers, and Glenn successfully completed three orbits around Earth, marking a major milestone in the Space Race.
Helping America Reach the Moon
Katherine Johnson’s contributions did not end with Project Mercury.
She calculated trajectories for the Apollo program, helping engineers plan missions that ultimately carried astronauts to the Moon and safely back to Earth. Her work also supported the Space Shuttle program and early concepts for future space exploration.
Her calculations contributed to some of the most significant achievements in aerospace history, demonstrating the critical role mathematics plays in exploration and discovery.
Recognition Long Overdue
For much of her career, Katherine Johnson worked behind the scenes, receiving little public recognition. That changed in later years as historians and researchers began highlighting the contributions of the women who helped build America’s space program.
In 2015, President Barack Obama awarded Katherine Johnson the Presidential Medal of Freedom, the nation’s highest civilian honor.
A year later, her story reached millions through the acclaimed film Hidden Figures, which introduced audiences around the world to Johnson and her colleagues Dorothy Vaughan and Mary Jackson.
The movie helped shine a long-overdue spotlight on the women whose brilliance helped change history.
A Legacy That Continues to Inspire
Katherine Johnson passed away on February 24, 2020, at the age of 101, leaving behind a legacy of excellence, perseverance, and intellectual curiosity.
Her work reminds us that history is often shaped not only by those who step into the spotlight but also by those working quietly behind the scenes to solve impossible problems.
Today, students pursuing careers in science, technology, engineering, and mathematics continue to draw inspiration from her life and achievements. Her story demonstrates that talent, determination, and curiosity can overcome even the greatest obstacles.
As NASA prepares for a new era of lunar exploration and future missions to Mars, Katherine Johnson’s legacy remains woven into the history of every successful journey beyond our planet.
Why We Remember
Forgotten Genius Friday celebrates innovators whose achievements deserve greater recognition. Katherine Johnson’s extraordinary mathematical talent helped make space exploration possible, proving that one brilliant mind can help change the course of history.
Her calculations guided astronauts through some of humanity’s greatest adventures—and her legacy continues to inspire the explorers of tomorrow.
Related Links
- NASA: Katherine Johnson Biography
- NASA History
- National Park Service: Katherine Johnson
- West Virginia State University
🧠 Discover the remarkable innovators, inventors, and trailblazers who helped shape our world but rarely receive the recognition they deserve. Share your thoughts in the comments and subscribe to the STM Daily News newsletter to catch every new Forgotten Genius Friday feature and more inspiring stories delivered to your inbox.
News
Joby Aviation and Toyota kick off manufacturing alliance to scale electric air taxi production
Joby Aviation and Toyota launch a joint venture to improve productivity, quality, and cost as they prepare to scale electric air taxi production.
Joby Aviation and Toyota Motor Corporation have launched the initial phase of a strategic manufacturing alliance aimed at accelerating commercial production of electric air taxis—an early step the companies say is designed to make “air mobility for all” a practical, everyday reality.
Announced June 30, 2026, the partnership formalizes a new joint venture that will combine Joby’s electric aviation development with Toyota’s production systems and operational expertise. The near-term focus: building the groundwork for commercial production while pushing improvements in productivity, quality, and cost—key factors as the industry moves from prototypes to scaled manufacturing.
What the joint venture is designed to do
According to the companies, the alliance will initially concentrate on:
- Establishing the foundation for commercial production capability
- Advancing manufacturing excellence with an emphasis on productivity, quality, and cost
- Supporting expansion of Joby’s production capacity as it works toward aircraft certification and prepares for anticipated demand
The announcement positions Toyota’s manufacturing playbook—known globally for lean production and continuous improvement—as a lever to help Joby move from development into repeatable, high-quality output at scale.
Why it matters: eVTOLs need scale, not just flight tests
Electric vertical take-off and landing (eVTOL) aircraft have become one of the most closely watched bets in next-generation transportation, but the path to viable air taxi services depends on more than successful test flights. Certification timelines, supply chain readiness, and the ability to produce aircraft consistently (and affordably) are often what separates promising technology from commercial reality.
By forming a joint venture focused on manufacturing readiness, Joby and Toyota are signaling that the next competitive frontier is industrialization—how quickly and reliably eVTOL aircraft can be built to meet safety standards and market demand.
Related Links for Further reading
- Joby Aviation (official): https://www.jobyaviation.com
- Joby Investor Relations / News (official updates & filings): https://ir.jobyaviation.com
- Toyota Newsroom (official): https://www.toyotanewsroom.com
- Toyota Global (corporate overview): https://global.toyota/en
- FAA Advanced Air Mobility / Air Taxis (context): https://www.faa.gov/air-taxis
What executives are saying
Joby founder and CEO JoeBen Bevirt emphasized the long-running relationship between the companies, calling the joint venture a reflection of shared confidence in the opportunity ahead.
“Toyota has been by Joby’s side for nearly a decade, providing invaluable guidance and support as we built the foundation for manufacturing our aircraft,” Bevirt said. “Together, we share a vision of making aerial mobility an everyday reality.”
Toyota Motor Corporation Chairman Akio Toyoda framed air mobility as an extension of the company’s broader mission.
“Since our founding, we’ve been guided by the philosophy of providing mobility for all,” Toyoda said, adding that Toyota views air mobility as “a natural extension of that philosophy—from the ground into the sky.”
About the companies
Joby Aviation (NYSE: JOBY) is a California-based transportation company developing an all-electric eVTOL air taxi. The company intends to operate its own air taxi service in cities worldwide and sell aircraft to other operators and partners.
Toyota (NYSE: TM) has operated in North America for nearly 70 years and says it is focused on sustainable, next-generation mobility through Toyota and Lexus brands. Toyota reports nearly 64,000 employees in North America, 14 manufacturing plants, and more than 1,800 dealerships. The company also noted that its North Carolina plant began assembling automotive batteries for electrified vehicles in 2025.
What to watch for next
For readers tracking the air taxi sector, the next milestones will likely center on:
- Details on how the joint venture will be structured operationally
- Updates on Joby’s certification progress and production ramp timelines
- Signs of how manufacturing improvements translate into cost reductions and throughput
- Additional agreements or expanded collaboration as the alliance progresses
While the companies highlighted expected benefits, they also noted the usual forward-looking risks—such as regulatory certification timelines, market conditions, and the ability to finalize additional agreements.
Source: Toyota Motor North America / PRNewswire (June 30, 2026)
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