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.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
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The Knowledge
💦 The Rocket Scientist Behind the Super Soaker
Lonnie Johnson, a NASA engineer, invented the Super Soaker, revolutionizing playtime after an accidental water release during an experiment. His success funded clean energy research and education initiatives.
It’s the ultimate summer toy. A backyard classic. A staple of water fights everywhere. But did you know the Super Soaker—one of the best-selling toys of all time—was invented by a NASA scientist?
This week on Forgotten Genius Fridays, part of our short video series The Knowledge, we’re telling the story of Lonnie Johnson, the brilliant engineer behind the water blaster that changed playtime forever.
👨🏾🔬 From Rocket Science to Soaking Wet
In 1982, Lonnie Johnson was working on a heat pump project in his bathroom. A former Air Force officer and NASA engineer, Johnson had already helped develop spacecraft systems, including work on the Galileo mission to Jupiter.
But one day, while experimenting with pressurized water and cooling systems, a valve released—and shot a stream of water across the room. That moment sparked a different kind of idea.
Johnson thought, “This would make a cool toy.”
🧪 The Road to the Super Soaker
Johnson built a prototype of a pressurized water gun unlike anything on the market. After years of rejections from toy companies, he finally licensed the design to Larami Corporation, a small toy maker that saw its potential.
In 1990, the Super Soaker hit store shelves—and exploded in popularity.
Within two years, it had sold over 20 million units, becoming a cultural phenomenon and sparking a line of high-powered water blasters. Eventually, Larami was acquired by Hasbro, which still sells Super Soakers today.
🌍 What Lonnie Johnson Did Next
Instead of just cashing in and disappearing, Johnson reinvested his success. He used Super Soaker royalties—estimated at over $1 billion in sales—to fund research in clean energy, including work on solid-state batteries and solar power.
He also founded the Johnson STEM Activity Center in Atlanta to help underserved students gain hands-on experience in science and technology.
📚 Learn more about Johnson’s inventions:
Lonnie Johnson’s Biography – Lemelson-MIT NIH Innovator Profile
🎥 Watch the Full Story in 60 Seconds
Catch our Forgotten Genius Fridays episode:
🎬 “Who Invented the Super Soaker?”
Now streaming on:
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🔍 Why This Story Matters
Lonnie Johnson wasn’t just a toy inventor—he’s a prime example of how innovation, curiosity, and perseverance can lead to unexpected breakthroughs. He turned a burst of water in his lab into a global toy empire, and then turned that empire into a platform for real-world change.
In a world that often forgets its geniuses, we’re proud to remember this one.
🧠 Now you know.
— STM Daily News
Related Links:
https://en.wikipedia.org/wiki/Super_Soaker
https://en.wikipedia.org/wiki/Lonnie_Johnson_(inventor)
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
STM Daily News is a multifaceted podcast that explores a wide range of topics, from life and consumer issues to the latest in food and beverage trends. Our discussions dive into the realms of science, covering everything from space and Earth to nature, artificial intelligence, and astronomy. We also celebrate the amateur sports scene, highlighting local athletes and events, including our special segment on senior Pickleball, where we report on the latest happenings in this exciting community. With our diverse content, STM Daily News aims to inform, entertain, and engage listeners, providing a comprehensive look at the issues that matter most in our daily lives. https://stories-this-moment.castos.com/
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aerospace
Boom Supersonic Update 2026: Overture Progress, XB-1 Milestones, and What’s Next
Boom Supersonic’s 2026 update: XB-1 test success, Overture production timeline, funding progress, and the challenges facing the return of commercial supersonic travel.
By STM Daily News Staff
The race to bring back commercial supersonic travel is accelerating once again, led by Boom Supersonic, a Colorado-based aerospace company aiming to succeed where Concorde left off. As of 2026, the company has achieved meaningful technical milestones—but still faces significant financial, regulatory, and industrial hurdles.
Here’s a comprehensive look at where Boom stands today, and what it means for the future of high-speed air travel.
XB-1 Demonstrator Completes Historic Test Program
Boom’s experimental aircraft, the XB-1, has successfully completed its flight test campaign, marking a critical step toward validating the company’s supersonic technology.
- Achieved multiple supersonic flights in 2025
- Demonstrated aerodynamic stability and performance
- Tested “boomless cruise” capabilities to reduce sonic disturbances
The XB-1 program served as a scaled demonstrator for the company’s flagship commercial jet, proving that modern materials, software, and engine integration can support efficient supersonic flight.
With testing complete, the aircraft is expected to be preserved as a prototype, representing a turning point in private-sector aerospace innovation.
Overture: Boom’s Commercial Supersonic Jet
The centerpiece of Boom’s vision is the Overture, a next-generation supersonic passenger aircraft designed to carry between 60 and 80 passengers at speeds approaching Mach 1.7.
Current projected timeline:
- Prototype rollout: Targeted for 2026
- First flight: Expected around 2027
- Commercial service entry: Late 2020s (estimated 2029–2030)
Unlike Concorde, which catered primarily to elite travelers, Boom aims to position Overture with business-class pricing, potentially expanding access to faster global travel.
The aircraft is also being designed with sustainability in mind, including compatibility with sustainable aviation fuel (SAF).
Funding and Financial Momentum
In recent developments, Boom Supersonic secured an additional $100 million in funding, reinforcing investor confidence in the company’s long-term vision.
However, building a supersonic passenger aircraft remains one of the most capital-intensive challenges in aviation. Continued fundraising and strategic partnerships will be essential as the company moves from prototype to production.
Boomless Cruise: A Potential Game-Changer
One of Boom’s most significant innovations is its focus on “boomless cruise,” a method of flying supersonically without producing an audible sonic boom on the ground.
If proven viable at scale, this technology could influence regulatory changes—particularly in the United States, where overland supersonic flight is currently restricted.
The ability to fly faster-than-sound over land would unlock major domestic routes, dramatically reducing travel times between cities like New York and Los Angeles.
Manufacturing Challenges and Delays
Despite technical progress, Boom’s manufacturing ambitions face uncertainty. A planned production facility in North Carolina has experienced delays, raising questions about when large-scale assembly will begin.
Scaling production from prototype to commercial aircraft remains one of the most difficult phases of any aerospace program, requiring supply chain coordination, workforce development, and regulatory alignment.
Industry Skepticism Remains
While Boom has secured interest from major airlines, skepticism persists within the aviation industry.
Key concerns include:
- Certification complexity and regulatory approval timelines
- Operational costs versus ticket pricing
- Long-term demand for supersonic travel
Even airline executives have expressed cautious optimism, with some suggesting the project’s success remains uncertain.
The Bigger Picture: A Defining Decade for Supersonic Travel
Boom Supersonic has moved beyond concept and into real-world testing, demonstrating that modern supersonic flight is technically achievable.
However, the next phase—bringing Overture to market—will determine whether supersonic passenger travel becomes a viable industry once again or remains an ambitious experiment.
If successful, Boom could redefine global travel times. If not, it will join a long list of bold aerospace ventures that struggled to overcome economic reality.
Sources and External Links
- Boom Supersonic – Year in Review
- XB-1 Aircraft Overview
- Overture Aircraft Specifications
- Funding Announcement
- Industry Perspective
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
The Knowledge
Metrolink Offers Fare-Free Rides for Earth Day 2026 Across Southern California
Metrolink offers fare-free rides for Earth Day 2026 across Southern California, encouraging sustainable travel and reduced emissions.
Last Updated on April 21, 2026 by Daily News Staff
Metrolink Offers Fare-Free Rides for Earth Day 2026
LOS ANGELES — April 22, 2026 — In a continued push toward sustainable transportation, Metrolink will once again offer systemwide free rides on Earth Day, inviting commuters and travelers to leave their cars behind and explore a cleaner way to move across the region.
A One-Day Opportunity to Ride Free
On Wednesday, April 22, passengers can board any Metrolink train — including the Arrow service — without purchasing a ticket. The initiative is part of the broader celebration of Earth Day, encouraging environmentally conscious travel choices.
The fare-free program is designed to appeal to both regular riders and first-time users, particularly those navigating Southern California’s persistent traffic congestion and rising fuel costs.
Encouraging Sustainable Travel Habits
“Earth Day is a reminder that small changes, like choosing public transit over driving one day a week, can have a meaningful impact on our environment,” said Doug Chaffee, chair of the Metrolink Board.
With gas prices continuing to strain household budgets, the agency hopes the initiative will inspire more residents to consider rail as part of their regular commute.
Regional Connections Expand Access
Metrolink’s Earth Day promotion aligns with similar efforts by other Southern California transit providers. Riders can seamlessly connect to services operated by: LA Metro and the Orange County Transportation Authority, Riverside County Transportation Commission, San Bernardino County Transportation Authority and Ventura County Transportation Commission.
These partnerships extend the reach of fare-free travel across a six-county region, making it easier for riders to explore destinations without relying on personal vehicles.
Service Adjustments and Rider Tips
Passengers should note that trains will operate on a reduced weekday schedule, implemented earlier this spring. Despite the adjustment, all Metrolink lines and station cities remain in service.
For those planning a trip:
- No ticket is required — simply board the train
- Bikes are welcome, with capacity ranging from three bikes per standard car to nine in designated bike cars
- A curated destination guide highlights attractions within walking or biking distance of stations
Environmental and Economic Impact
Metrolink is also promoting its Personal Impact Calculator, a digital tool that allows riders to estimate how switching from driving to rail can reduce greenhouse gas emissions and lower fuel expenses.
A Broader Trend in Public Transit
Fare-free transit days have gained traction nationwide as agencies look to boost ridership and promote sustainability. Southern California’s expansive commuter rail network makes it particularly well-suited for such initiatives, offering a viable alternative to one of the country’s most car-dependent regions.
Bottom Line
Metrolink’s Earth Day promotion is more than a one-day free ride — it’s a strategic effort to shift commuter behavior, reduce environmental impact, and showcase the convenience of regional rail. For Southern Californians, April 22 presents a low-risk opportunity to rethink how they travel.
Source: Metrolink
https://metrolinktrains.com/news/metrolink-goes-fare-free-for-earth-day-on-april-22
Dive into “The Knowledge,” where curiosity meets clarity. This playlist, in collaboration with STMDailyNews.com, is designed for viewers who value historical accuracy and insightful learning. Our short videos, ranging from 30 seconds to a minute and a half, make complex subjects easy to grasp in no time. Covering everything from historical events to contemporary processes and entertainment, “The Knowledge” bridges the past with the present. In a world where information is abundant yet often misused, our series aims to guide you through the noise, preserving vital knowledge and truths that shape our lives today. Perfect for curious minds eager to discover the ‘why’ and ‘how’ of everything around us. Subscribe and join in as we explore the facts that matter. https://stmdailynews.com/the-knowledge/
