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.
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 oblatespheroid. 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.
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Our distance from the Sun is not why we have seasons. NASA
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.
Because of the tilt of the Earth, we are able to experience the seasons. Stephanie Spera
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.
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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.
The Earth’s axis is always tilted at 23.5 degrees. Stephanie Spera
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.
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Workers who are in frequent contact with potentially sick animals are at high risk of bird flu infection.
Costfoto/NurPhoto via Getty ImagesRon Barrett, Macalester College
Disease forecasts are like weather forecasts: We cannot predict the finer details of a particular outbreak or a particular storm, but we can often identify when these threats are emerging and prepare accordingly.
The viruses that cause avian influenza are potential threats to global health. Recent animal outbreaks from a subtype called H5N1 have been especially troubling to scientists. Although human infections from H5N1 have been relatively rare, there have been a little more than 900 known cases globally since 2003 – nearly 50% of these cases have been fatal – a mortality rate about 20 times higher than that of the 1918 flu pandemic. If the worst of these rare infections ever became common among people, the results could be devastating.
Approaching potential disease threats from an anthropological perspective, my colleagues and I recently published a book called “Emerging Infections: Three Epidemiological Transitions from Prehistory to the Present” to examine the ways human behaviors have shaped the evolution of infectious diseases, beginning with their first major emergence in the Neolithic period and continuing for 10,000 years to the present day.
Viewed from this deep time perspective, it becomes evident that H5N1 is displaying a common pattern of stepwise invasion from animal to human populations. Like many emerging viruses, H5N1 is making incremental evolutionary changes that could allow it to transmit between people. The periods between these evolutionary steps present opportunities to slow this process and possibly avert a global disaster.
Spillover and viral chatter
When a disease-causing pathogen such as a flu virus is already adapted to infect a particular animal species, it may eventually evolve the ability to infect a new species, such as humans, through a process called spillover.
Spillover is a tricky enterprise. To be successful, the pathogen must have the right set of molecular “keys” compatible with the host’s molecular “locks” so it can break in and out of host cells and hijack their replication machinery. Because these locks often vary between species, the pathogen may have to try many different keys before it can infect an entirely new host species. For instance, the keys a virus successfully uses to infect chickens and ducks may not work on cattle and humans. And because new keys can be made only through random mutation, the odds of obtaining all the right ones are very slim.
Given these evolutionary challenges, it is not surprising that pathogens often get stuck partway into the spillover process. A new variant of the pathogen might be transmissible from an animal only to a person who is either more susceptible due to preexisting illness or more likely to be infected because of extended exposure to the pathogen.
Even then, the pathogen might not be able to break out of its human host and transmit to another person. This is the current situation with H5N1. For the past year, there have been many animal outbreaks in a variety of wild and domestic animals, especially among birds and cattle. But there have also been a small number of human cases, most of which have occurred among poultry and dairy workers who worked closely with large numbers of infected animals.
Pathogen transmission can be modeled in three stages. In Stage 1, the pathogen can be transmitted only between nonhuman animals. In stage 2, the pathogen can also be transmitted to humans, but it is not yet adapted for human-to-human transmission. In Stage 3, the pathogen is fully capable of human-to-human transmission.Ron Barrett, CC BY-SA
Epidemiologists call this situation viral chatter: when human infections occur only in small, sporadic outbreaks that appear like the chattering signals of coded radio communications – tiny bursts of unclear information that may add up to a very ominous message. In the case of viral chatter, the message would be a human pandemic.
Sporadic, individual cases of H5N1 among people suggest that human-to-human transmission may likely occur at some point. But even so, no one knows how long or how many steps it would take for this to happen.
Influenza viruses evolve rapidly. This is partly because two or more flu varieties can infect the same host simultaneously, allowing them to reshuffle their genetic material with one another to produce entirely new varieties.
Genetic reshuffling – aka antigenic shift – between a highly pathogenic strain of avian influenza and a strain of human influenza could create a new strain that’s even more infectious among people.Eunsun Yoo/Biomolecules & Therapeutics, CC BY-NC
These reshuffling events are more likely to occur when there is a diverse range of host species. So it is particularly concerning that H5N1 is known to have infected at least 450 different animal species. It may not be long before the viral chatter gives way to larger human epidemics.
Reshaping the trajectory
The good news is that people can take basic measures to slow down the evolution of H5N1 and potentially reduce the lethality of avian influenza should it ever become a common human infection. But governments and businesses will need to act.
People can start by taking better care of food animals. The total weight of the world’s poultry is greater than all wild bird species combined. So it is not surprising that the geography of most H5N1 outbreaks track more closely with large-scale housing and international transfers of live poultry than with the nesting and migration patterns of wild aquatic birds. Reducing these agricultural practices could help curb the evolution and spread of H5N1.
Large-scale commercial transport of domesticated animals is associated with the evolution and spread of new influenza varieties.ben/Flickr, CC BY-SA
People can also take better care of themselves. At the individual level, most people can vaccinate against the common, seasonal influenza viruses that circulate every year. At first glance this practice may not seem connected to the emergence of avian influenza. But in addition to preventing seasonal illness, vaccination against common human varieties of the virus will reduce the odds of it mixing with avian varieties and giving them the traits they need for human-to-human transmission.
At the population level, societies can work together to improve nutrition and sanitation in the world’s poorest populations. History has shown that better nutrition increases overall resistance to new infections, and better sanitation reduces how much and how often people are exposed to new pathogens. And in today’s interconnected world, the disease problems of any society will eventually spread to every society.
For more than 10,000 years, human behaviors have shaped the evolutionary trajectories of infectious diseases. Knowing this, people can reshape these trajectories for the better.Ron Barrett, Professor of Anthropology, Macalester College
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Is Chipotle Closing All Its Restaurants After Filing for Bankruptcy? Here’s What We Know
Rumors of Chipotle filing for bankruptcy and closing locations stemmed from a misreported article about a spinoff restaurant. Chipotle confirmed these claims are false and plans to open 345 new restaurants, ensuring customers it remains open for business.
Recent rumors circulating on social media have left many Chipotle fans in a state of panic, with claims that the beloved restaurant chain is filing for bankruptcy and set to close all its locations. Let’s set the record straight and find out what’s really happening.
According to KTLA, the frenzy began when the Union Rayo media outlet published a story on March 20 about the closure of a Chipotle spinoff restaurant called Farmesa Fresh Eatery. Unfortunately, the article mistakenly included a photo of Chipotle, and this misinformation quickly spread like wildfire across social platforms.
Chipotle is famous for its generously-sized burritos, bowls, quesadillas, and tacos, proudly serving organic ingredients at nearly 4,000 locations worldwide. Unsurprisingly, the rumors sent burrito lovers into a frenzy. One social media user expressed disbelief, questioning, “How is Chipotle going bankrupt when I get a bowl with extra chicken and guac every day????”
Amidst the chaos, another user humorously suggested, “They’re talking about Chipotle closing, I’ll chain my wrist to the door don’t play with me,” highlighting the deep connection many have to the restaurant.
In response to the widespread concerns, Chipotle issued a statement to clarify the situation. A spokesperson for the chain told Good Morning America, “The claim that Chipotle is closing restaurants is false. The false information stemmed from an inaccurate online article confusing Chipotle with a venture it tested in 2023. The story has since been corrected.”
Furthermore, as a testament to their growth, Chipotle plans to open 345 new restaurants this year. This expansion clearly indicates that the chain is on solid ground and committed to serving its loyal customers for years to come.
So, if you were worried about your next burrito fix, rest easy! Chipotle is not closing its doors, and the rumors can safely be put to rest. Keep enjoying your favorite meals, and stay tuned for those new locations popping up soon!
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Dolores Raphael is a dedicated writer and blogger focused on health, fitness, and everyday living. She shares practical tips and inspiring insights to help others lead a balanced and vibrant lifestyle. one of her passions is Pickleball.
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Val Kilmer at Cannes in 2005. Image Credit: Georges Biard
LOS ANGELES (AP) — In a heartbreaking loss to the entertainment world, Val Kilmer, the intense and versatile actor known for iconic roles in films such as “Top Gun,” “Batman Forever,” and “The Doors,” has passed away at the age of 65. Kilmer died on Tuesday night in Los Angeles, surrounded by his family and friends, as confirmed by his daughter, Mercedes Kilmer, in an email to The Associated Press.
Kilmer’s death was attributed to pneumonia, following a long and courageous battle with throat cancer that he had been diagnosed with in 2014, a struggle that led to two tracheotomies.
Reflecting on his tumultuous yet inspiring journey, Kilmer shared in the documentary “Val” (2021), “I have behaved poorly. I have behaved bravely. I have behaved bizarrely to some. I deny none of this and have no regrets because I have lost and found parts of myself that I never knew existed. And I am blessed.” His words are a testament to his remarkable resilience, artistry, and unique perspective on life.
Val Kilmer
Kilmer was a prodigy in the performing arts, becoming the youngest actor ever admitted to the prestigious Juilliard School when he enrolled in 1981. His breakthrough came with the 1984 spy spoof “Top Secret!” and he quickly rose to fame with a series of successful films, including the beloved comedy “Real Genius” in 1985. He showcased his comedic talents in later works, such as “MacGruber” and “Kiss Kiss Bang Bang.”
The pinnacle of Kilmer’s career arguably occurred in the early 1990s, where he solidified his status as a leading man. Among his most memorable roles were Doc Holliday in “Tombstone” (1993), Elvis Presley in “True Romance,” and the cunning bank-robbing demolition expert in Michael Mann’s “Heat” (1995), alongside cinematic legends Al Pacino and Robert De Niro.
Despite the acclaim, Kilmer’s career was not without its challenges. A 1996 Entertainment Weekly cover story famously dubbed him “The Man Hollywood Loves to Hate,” citing conflicts with directors and a reputation for being difficult on set. Notable figures, including directors John Frankenheimer and Joel Schumacher, described his work as challenging; however, many others, like director D. J. Caruso, defended Kilmer’s commitment to depth and character immersion.
After delivering memorable performances in adult dramas, Kilmer took a slight detour, engaging in smaller films, such as David Mamet’s “Spartan,” and portraying the troubled 1970s adult film star John Holmes in “Wonderland” (2003). He also embraced the stage with a one-man show, “Citizen Twain,” where he explored the complex life of Mark Twain.
Hailing from the Chatsworth neighborhood of Los Angeles, Kilmer’s early life was marred by tragedy with the loss of his younger brother, Wesley, to a seizure — a poignant event that would forever resonate with him. Throughout his life, Kilmer sought inspiration from his brother, often reflecting on the artistic potential he believed Wesley would have achieved.
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As a multi-talented artist, Kilmer not only acted but also wrote poetry, with two published collections, including “My Edens After Burns.” In 2012, he received a Grammy nomination for his spoken word album, “The Mark of Zorro.” He continued to explore various creative outlets and was known for his dedication to visual art and his Christian Science faith.
His personal life saw relationships with notable personalities, including singer Cher, and he was previously married to actor Joanne Whalley, with whom he shares two children, Mercedes and Jack.
In a final testament to his remarkable life and career, Kilmer asserted, “I have no regrets. I’ve witnessed and experienced miracles.” Val Kilmer leaves behind a rich legacy, characterized by his complex characters and deep artistic contributions that will forever resonate with audiences. The film industry has lost a true icon, and his presence will be deeply missed.
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Ron Barrett, Professor of Anthropology, Macalester College
This article is republished from The Conversation under a Creative Commons license. Read the original article.
