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Why does a plane look and feel like it’s moving more slowly than it actually is?

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Why does a plane look and feel like it’s moving more slowly than it actually is?

Without a point of reference, it can be hard to tell just how fast an airplane is traveling.
Daniel Berehulak/Getty Images News via Getty Images

Sara Nelson, Iowa State University

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 does a plane look and feel like it’s moving more slowly than it actually is? – Finn F., age 8, Concord, Massachusetts


A passenger jet flies at about 575 mph once it’s at cruising altitude. That’s nearly nine times faster than a car might typically be cruising on the highway. So why does a plane in flight look like it’s just inching across the sky?

I am an aerospace educator who relies on the laws of physics when teaching about aircraft. These same principles of physics help explain why looks can be deceiving when it comes to how fast an object is moving.

Moving against a featureless background

If you watch a plane accelerating toward takeoff, it appears to be moving very quickly. It’s not until the plane is in the air and has reached cruising altitude that it appears to be moving very slowly. That’s because there is often no independent reference point when the plane is in the sky.

A reference point is a way to measure the speed of the airplane. If there are no contrails or clouds surrounding it, the plane is moving against a completely uniform blue sky. This can make it very hard to perceive just how fast a plane is moving.

And because the plane is far away, it takes longer for it to move across your field of vision compared to an object that is close to you. This further creates the illusion that it is moving more slowly than it actually is.

These factors explain why a plane looks like it’s going more slowly than it is. But why does it feel that way, too?

A passenger’s perception on the plane

A plane feels like it’s traveling more slowly than it is because, just like when you look up at a plane in the sky, as a passenger on a plane, you have no independent reference point. You and the plane are moving at the same speed, which can make it difficult to perceive your rate of motion relative to the ground beneath you. This is the same reason why it can be hard to tell that you are driving quickly on a highway that is surrounded only by empty fields with no trees.

Perspective from a plane window of the plane's shadow against a brown field with the plane's white wing visible on the left side.
Watching the speed of a plane’s shadow can help you assess how quickly a plane is moving.
Saul Loeb/AFP via GettyImages

However, there are a couple of ways you might be able to understand just how fast you are moving.

Can you see the plane’s shadow on the ground? It can give you perspective on how fast the plane is moving relative to the ground. If you are lucky enough to spot it, you will be amazed at how fast the plane’s shadow passes over buildings and roads. You can get a real sense of the 575 mph average speed of a cruising passenger plane.

Another way to understand how fast you are moving is to note how fast thin, spotty cloud cover moves over the wing. This reference point gives you another way to “see” or perceive your speed. Remember though, that clouds aren’t typically stationary; they’re just moving very slow relative to the plane.

An airplane passes over thin, spotty cloud cover.

Although it can be difficult to discern just how fast a plane is actually moving, using reference points to gain perspective can help tremendously.

Has your interest in aviation been sparked? If so, there are a lot of great career opportunities in aeronautics.


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.The Conversation

Sara Nelson, Director of the NASA Iowa Space Grant Consortium, Iowa State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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FDA bans Red 3 dye from food and drugs – a scientist explains the artificial color’s health risks and long history

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theconversation.com – Lorne J. Hofseth, Professor and Associate Dean for Research, College of Pharmacy, University of South Carolina – 2025-01-23 07:45:00

Look out for Red 3, FD&C Red No. 3, erythrosine or E127 in the ingredients list of your favorite processed foods.

Anhelina Chumak/iStock via Getty Images Plus

Lorne J. Hofseth, University of South Carolina

Red 3 – also called FD&C Red No. 3, erythrosine or E127 – has been widely used in food, cosmetics and pharmaceuticals since its FDA approval in 1969. You’ve likely encountered Red 3 before. It’s a common additive to many candies, beverages, baked goods, cereals, maraschino cherries and gelatin desserts, as well as certain medications, syrups and cosmetics.

However, mounting scientific evidence suggests that consuming Red 3 poses significant health risks. These risks prompted California to ban its use in food in 2023 and the Food and Drug Administration to ban its use in both food and pharmaceuticals nationwide on Jan. 15, 2025.

As a researcher studying inflammation and cancer, I investigate how synthetic food dyes affect human health. Stricter regulations reflect growing concerns over the negative physiological effects of Red 3 and other synthetic dyes on your body, including causing cancer.

Health risks of Red 3

Over the past 35 years, an increasing amount of scientific evidence has identified the negative health effects of Red 3. While researchers haven’t yet established a direct link between Red 3 and cancer in people, substantial evidence from animal studies points to its carcinogenic potential.

First, Red 3 disrupts thyroid hormone regulation through several mechanisms. It inhibits the thyroid gland’s ability to absorb iodine, a key component for synthesizing thyroid hormones, and blocks an enzyme essential for converting one thyroid hormone to another, contributing to thyroid dysfunction. Along with other impairments in thyroid hormone function, Red 3 increases the risk of thyroid-related disorders.

Second, Red 3 may promote thyroid tumor formation. Several studies exposing rats and pigs to Red 3 observed enlarged tumorous thyroid glands and abnormalities in hormone regulation.

Third, Red 3 can have toxic effects on the brain in multiple ways. Rat studies have found that this synthetic dye increases oxidative stress, which damages tissues, and reduces the antioxidants that control oxidative stress, impairing communication between neurons. Studies in rodents also found that Red 3 triggers neuroinflammation that leads to neuronal damage and dysfunction. Additionally, Red 3 may interact with the amyloid-beta peptides linked to neurodegenerative conditions like Alzheimer’s disease and worsen those conditions.

Regulatory momentum

Red 3 first faced scrutiny in the 1980s when several animal studies linked it to thyroid tumors in male rats. This led to its 1990 ban in cosmetics in the U.S., although its use in food persisted under industry pressure. While the European Union restricted the use of Red 3 to only certain types of processed cherries in 1994, the U.S. has lagged behind.

California’s 2023 ban of Red 3 in foods, effective in 2027, reignited debate on Red 3 and its link to cancer and spurred 24 organizations to advocate for federal action.

Several countries have banned the use of Red 3 in food. Until January 2025, the U.S. had only banned it in cosmetics and topical drugs.

This debate culminated in the FDA’s nationwide ban in January 2025. While the FDA cites no direct evidence of Red 3’s carcinogenic effect in people, it acknowledges that animal studies provide sufficient basis for regulatory action. The FDA’s decision aligns with the 1958 Delaney Clause of the Federal Food, Drug and Cosmetic Act, mandating a ban on additives shown to cause cancer in humans or animals.

Notably, it took over 35 years from the initial findings of thyroid cancer in rodents to the eventual ban in 2025.

A path forward

The progression from Red 3’s approval to its prohibition highlights the conflict between industrial interests and public health. Continued vigilance over Red 3 could help the nation prioritize consumer safety.

Under the FDA’s mandate, manufacturers must reformulate food products and ingested drugs to leave out Red 3 by January 2027 and January 2028, respectively. While some countries still permit use of Red 3, U.S. imports must meet domestic safety standards. Harmonizing global standards on regulating and evaluating synthetic dyes is essential to protect consumer health.

Close-up of colorful cereal loops

Stronger, more standardized regulation of synthetic food dyes would help protect consumer health.

choness/iStock via Getty Images

Several companies selling ultra-processed foods have begun the shift away from synthetic dyes. In 2016, Mars announced plans to remove all artificial colors from its human food products over a five-year period. In 2024, General Mills announced that it would eliminate artificial colors and flavors from its products.

Consumers can protect themselves from Red 3 exposure by reading ingredient labels for “FD&C Red No. 3” or “E127” and choosing products that use natural dyes. Preparing homemade foods with natural color alternatives like beet juice or turmeric is another option. Supporting dye-free brands and staying informed about regulatory changes can further reduce your exposure while promoting safer food practices.

Ongoing research and policy reforms focused on public safety could help ensure that food additives like Red 3 no longer put consumer health at risk.The Conversation

Lorne J. Hofseth, Professor and Associate Dean for Research, College of Pharmacy, University of South Carolina

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As Gaza ceasefire takes hold, Israeli forces turn to Jenin – a regular target seen as a center of Palestinian resistance

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theconversation.com – Maha Nassar, Associate Professor in the School of Middle Eastern and North African Studies, University of Arizona – 2025-01-22 17:42:00

Maha Nassar, University of Arizona

Just two days after a shaky ceasefire took hold in the Gaza Strip, Israel on Jan. 21, 2025, launched a large-scale incursion of the Jenin refugee camp in the West Bank.

Soldiers raided hundreds of homes in the West Bank city in what the Israeli military called a “counterterrorism” operation, aiming to reassert control there. Many analysts have suggested the raid is an attempt by Israeli Prime Minister Benjamin Netanyahu to appease far-right members of his coalition who oppose the ceasefire deal.

Whatever the motive, the offensive has been devastating for many of the camp’s residents. The Israeli military has destroyed infrastructure, closed entrances to local hospitals and forcibly displaced about 2,000 families, according to reports on the raids. As it was, life for inhabitants of the densely populated camp – home to some 24,000 Palestinian refugees – was hard. The West Bank director of UNRWA, the U.N. agency overseeing refugees, recently described camp conditions as “nearly uninhabitable.”

The focus of the latest Israeli operation is not new. The Jenin refugee camp, on the western edge of the town of Jenin in the north of the occupied West Bank, has often experienced violence between Israeli soldiers and Palestinian militants.

That violence has escalated since the Oct. 7, 2023, attacks, when Hamas gunmen led an incursion into Israel in which around 1,200 people were killed. The camp has faced repeated large-scale military operations by Israeli forces, including drone strikes, ground raids, and airstrikes that have caused widespread destruction. Meanwhile, Israeli settlers have torched Palestinian cars and properties, with 64 such attacks in the Jenin area alone since Oct. 7, 2023. Last December, the Palestinian Authority, which coordinates with Israel to oversee security in parts of the West Bank, also attacked local militants.

These events have deepened political tensions and worsened the economic and humanitarian crises in the West Bank. According to the U.N., more than a quarter of the 800-plus Palestinians killed in the West Bank since Oct. 7 attack have come from the Jenin district; several Israeli civilians have also been killed in the West Bank during the same period.

As a scholar of Palestinian history, I see this recent episode as the latest chapter in a much longer history of Palestinian displacement and defiance of Israeli occupation. Understanding this history helps explain why the Jenin camp in particular has become a target of Israeli offensives and a center of Palestinian militant resistance.

Camp conditions

Jenin, an agricultural town that dates back to ancient times, has long been a center of Palestinian resistance. During the 1948 Arab-Israeli War, Arab fighters successfully pushed back Israeli attempts to capture the town.

At the end of that war, the town became a refuge for some of the hundreds of thousands of Palestinian refugees who fled or were expelled from lands that became part of Israel. Jenin, along with the hilly interior of Palestine known as the West Bank, was annexed by Jordan.

The U.N. Relief and Works Agency established the Jenin camp in 1953, just west of the city. Since then, the agency has provided basic services to the camp’s residents, including food, housing and education.

Camp conditions have always been difficult. In the early years of the camp, refugees had to stand in long lines to receive food rations, and for decades their cramped homes lacked electricity or running water.

The Jenin camp soon became the poorest and most densely populated of the West Bank’s 19 refugee camps. And given its location near the “Green Line” – the armistice line that serves as Israel’s de facto border – camp residents who were expelled from northern Palestine could actually see the homes and villages from which they were expelled. But they were prevented from returning to them.

The rise of militancy

Since 1967, Jenin, along with the rest of the West Bank, has been occupied by the Israeli military.

The Israeli occupation of Jenin compounded the difficulties of these refugees. As stateless Palestinians, they couldn’t return home. But under Israeli occupation, they couldn’t live freely in Jenin, either. Human rights groups have long documented what has been described as “systematic oppression,” which includes discriminatory land seizures, forced evictions and travel restrictions.

Seeing no other path forward, many of the camp’s young refugees turned to armed resistance.

In the 1980s, groups such as the Black Panthers, which was affiliated with the Palestinian nationalist Fatah organization, launched attacks on Israeli targets in an effort to end the occupation and liberate their ancestral lands. Throughout the first intifada – a Palestinian uprising lasting from 1987 to 1993 – the Israeli army raided the Jenin camp many times, seeking to arrest members of militant groups. In the process, Israeli forces also sometimes demolished family members’ homes and arrested relatives. Such acts of apparent collective punishment reinforced the idea for many Palestinians that the Israeli occupation could only be ended by force.

A group of men in headscarves stand in front of flags and banners. One holds a pistol up in the air.
Members of the militant group Fatah in Jenin in 1991.
Esaias Baitel/Gamma-Rapho via Getty Images)

The Oslo peace process of the 1990s – which consisted of a series of meetings between Israeli government and Palestinian representatives – led some former militants to hope that the occupation could be ended through negotiations instead. But Jenin’s camp residents remained marginalized in the West Bank and sealed off from Israel, seeing little improvement in their lives, even after the transfer of administrative powers from Israel to the Palestinian Authority in 1995.

Independent projects like the The Freedom Theatre provided some relief to the camp’s refugee children, but it was not enough to overcome the grinding poverty or the violence they faced from Israeli soldiers and settlers. By the time the second intifada broke out in 2000, many of the camp’s teenagers joined militant groups. That included Freedom Theatre co-founder Zakaria Zubeidi, who joined the Fatah-affiliated Al-Aqsa Martyrs Brigade. Like the youth of the 1980s, they, too, concluded that only armed resistance would bring an end to the occupation.

A cycle of violence?

In April 2002, the Israeli army invaded the Jenin camp, hoping to put an end to such armed groups. There were fierce clashes between Israeli soldiers and young Palestinian men in the camp, solidifying Jenin’s reputation among Palestinians as “the capital of the resistance.”

The lack of progress on peace talks since then, Israel’s settlement building on occupied land – deemed illegal under international law – and the inclusion of hard-line Israeli politicians in the government have exacerbated resentment in the camp. Polls show Palestinians increasingly support armed resistance.

Seeking to protect the camp from Israeli incursions, in 2021 a group of local residents formed the Jenin Brigades. While its founder was affiliated with Palestinian Islamic Jihad, the group quickly drew in militants from various political factions. Members acquired weapons, patrolled the streets and fought off Israeli military incursions. By 2022, they had declared parts of the camp to be “liberated” from the Israeli occupation.

Seemingly alarmed by the increase in militancy and the stockpiling of weapons in the camp, Israel dramatically stepped up its raids in 2022. It was during such a raid that Palestinian American journalist Shireen Abu Akleh was killed by an Israeli soldier.

On July 3, 2023, the Israeli military again invaded Jenin, withdrawing after two days of heavy aerial bombardment and a ground invasion that killed 12 Palestinians and wounded over 100.

The latest offensive could well surpass that death toll, with at least 10 killed in the first day of fighting. But the militancy associated with the camp was built on decades of resistance and defiance to occupation that Israel has had little success in extinguishing. Similarly this time, I believe, such militancy within the camp will only increase with the latest deaths and destruction.

This article is an updated version of a story that was first published by The Conversation on July 5, 2023.The Conversation

Maha Nassar, Associate Professor in the School of Middle Eastern and North African Studies, University of Arizona

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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What is seditious conspiracy, which is among the most serious crimes Trump pardoned?

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theconversation.com – Amy Cooter, Director of Research, Academic Development and Innovation at the Center on Terrorism, Extremism and Counterterrorism, Middlebury – 2025-01-22 15:12:00

The Jan. 6, 2021, storming of the Capitol was the result of a planned conspiracy to disrupt the government, prosecutors alleged.
AP Photo/John Minchillo

Amy Cooter, Middlebury

Several of the highest-profile figures in the Jan. 6, 2021, insurrection were charged with, and convicted of, the crime of seditious conspiracy, which is defined as the act of getting together with other people to overthrow the government. They were among the roughly 1,500 people involved in the insurrection who were pardoned or had their prison sentences commuted by Donald Trump on his first day in office.

Seditious conspiracy is a serious crime of conspiring to overthrow the government or stop its normal functioning. Historically, seditious conspiracy has been difficult to successfully prosecute.

In 2009, for example, a state judge ruled that prosecutors had failed to provide sufficient evidence for members of the Michigan Hutaree militia to go to trial on that charge. Certain militia members had been accused of plotting violence against police officers. While some members faced other charges for their actions, the judge determined that a plot against law enforcement was not sufficient to support charges of attempting to overthrow the government.

In contrast, the U.S. Department of Justice charged 18 people associated with the Jan. 6 attack on the U.S. Capitol with that crime, asserting that they had intended to “oppose by force the lawful transfer of presidential power” or had committed other actions that would undermine the entire system of government.

Of those 18, four pleaded guilty, and 10 were found guilty at trial. The remaining four were found not guilty of seditious conspiracy but were convicted of other crimes that were related to the insurrection.

Capitol entry not required

Oath Keepers militia leader Stewart Rhodes’ seditious conspiracy conviction was especially significant because, unlike some other defendants, Rhodes did not physically enter the Capitol building. He was instead in “the restricted area of Capitol grounds,” according to a Justice Department statement.

His conviction was based in part on his communications, including text messages, both before Jan. 6 and on the day itself. Prosecutors successfully argued that these communications were part of a broader conspiracy to disrupt the election certification by organizing and encouraging others to participate in more direct action.

Two men walk in front of a group of masked men with the Washington Monument in the background.
Proud Boys members Joseph Biggs, left, and Ethan Nordean, right with megaphone, walk toward the U.S. Capitol in Washington, D.C., on Jan. 6, 2021.
AP Photo/Carolyn Kaster

Militias respond to convictions – and clemency

Many observers believed successful prosecutions for these charges sent a strong message that violence against a democratically elected government was not acceptable.

Scholars of militia activity like me saw a period of relative quiet through much of Joe Biden’s presidency, which was, in part, likely due to the consequences the Jan. 6 defendants faced.

Some groups, however, continued social media discussions of their beliefs that the 2020 election had been “stolen,” as Trump continues to falsely claim, and which was used as justification by militia members for their attack. Trump himself said publicly he thought the defendants were unjustly persecuted and promised to pardon them if and when he returned to power.

The full effect that the pardons will have on militia actors and related groups in coming years is uncertain: Will the pardons send the message to all Americans that political violence is acceptable, or at least that it can be overlooked or forgiven if the right political figures are in power?The Conversation

Amy Cooter, Director of Research, Academic Development and Innovation at the Center on Terrorism, Extremism and Counterterrorism, Middlebury

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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