Why Do I Have to Go to Sleep?

Chloe Effron
Chloe Effron

Kids ask a lot of questions.

mental_floss has answers. Today we launch WHY?, our new series for kids and parents. We'll tackle all types of questions children have about how the world works by providing science-based, kid-friendly content. Our answers are written with early readers (ages 4–7) in mind, but we think they're interesting—and educational—for everyone.

Have a question? Send it to why@mentalfloss.com. 

Sleep is a must for all animals, including you. You must sleep to live. When we sleep it may seem like we’re not doing much. But this is when our bodies are busy growing, healing, and learning—especially our brains. They make sense of the lessons, games, words, feelings, and thoughts we had during the day. 


We have something inside our bodies called a circadian (sir-CAY-dee-an) clock that tells our bodies when it’s time to sleep. It’s not a real clock! The circadian clock is a system controlled by neurons, or brain cells, behind your eyes that react to light. This clock tells us to be awake during the day and to go to sleep at night.


Because the human brain evolved before we created electric lights. You’re not reading this on the computer or phone in bed, right? Because that’s a bad idea. The light from the computer tricks your circadian clock into acting like it’s daytime, so you’re not as sleepy. When you stay up late and lose sleep, your brain and body don’t work as well the next day. It’s harder to learn new things, remember old things, and not be cranky. 

For fun further reading, check out MadScieNet's answer to the question, "Do worms sleep?"


WHY

How to See Venus and the Moon Share a ‘Kiss’ in a Rare Astronomical Event This Week

Mike Hewitt/iStock via Getty Images
Mike Hewitt/iStock via Getty Images

Venus is visible in the evening or morning sky for most of the year, but this Thursday, the second planet from the sun won't be alone in its spot above the horizon. As Travel + Leisure reports, Venus, also known as the "evening star," will appear right next to a crescent moon following the sunset on February 27, resulting in a rare celestial "kiss."

Why will Venus be close to the moon?

Venus is often among the first "stars" to become visible at twilight (though it's really a planet), and it's the brightest object in the night sky aside from the moon. Between January 1 and May 24, it shines brightly above the western horizon. For a few weeks in early May and late June, Venus is washed out by the light of the sun, and from June 13 to December 31, it's easiest to see in the eastern sky around sunrise.

This week, Venus will be in the perfect position to share a "kiss" with the night's brightest object. All the planets, including Venus, appear to traverse the same path across the night sky called the ecliptic. The moon follows a similar trajectory, and on some nights, the celestial body seems to come very close to the planets that also occupy the plane. This effect is just an illusion; while they will appear to be nearly touching on Thursday, the moon will actually be 249,892 miles from Earth on February 27, while Venus will be 84 million miles away.

The Moon just entered its "new" phase on Sunday, and it will only be partially illuminated by the time it meets up with Venus. The waxing crescent moon will rise in the perfect position in the western sky on Thursday to create a joint spectacle with our planetary neighbor.

When to see Venus and the moon "kiss"

The kiss between the moon and Venus can be spotted in the hours after sunset on Thursday, February 27. When you notice it getting dark, head outside and look to the southwest horizon if you live in the Northern Hemisphere. That will give you your best chance at catching the special event. If you miss it this week, you won't have to wait long for your next opportunity to see the Moon kiss Venus: The two bodies will return to a similar position on March 28, 2020.

[h/t Travel + Leisure]

Katherine Johnson, the NASA Legend Who Inspired 'Hidden Figures,' Dies at Age 101

Alex Wong/Getty Images
Alex Wong/Getty Images

Mathematician and NASA legend Katherine Johnson has died at age 101, The New York Times reports. The inspiration for the 2016 movie Hidden Figures, Johnson was best known for calculating the equations that sent the first astronauts to the moon and breaking barriers in science and technology as a black woman in the civil rights era.

Katherine Johnson's knack for numbers was apparent from a young age. She was born in White Sulphur Springs, West Virginia, on August 26, 1918, and she enrolled directly into the second grade as soon as she was old enough to go to school. She graduated college summa cum laude at age 18 after taking every math class that was available to her.

In the 1950s, NASA hired Johnson to be one of the women "computers" tasked with crunching the numbers that were vital to getting missions off the ground. She was personally responsible for confirming the equations that sent astronaut John Glenn into orbit in 1962. After requesting that Johnson double-check the computer's math by hand, he reportedly said, “If she says they’re good, then I’m ready to go.”

Her biggest job was working on the Apollo 11 mission. Johnson worked closely with NASA's engineers to calculate when and where to launch the first manned shuttle to the moon, fully aware that even a tiny error could lead to a national tragedy. On July 20, 1969, the first astronauts landed on the moon, thanks in part to her computing power.

As a black woman working in a primarily white male-dominated field in the 1960s, Johnson's contributions to space history went unrecognized for years. She lived long enough to become one of the few marginalized figures in science to receive some much-deserved, albeit overdue, accolades. In 2015, President Barack Obama awarded Johnson the Presidential Medal of Freedom, and in 2016, her work at NASA was depicted in the Oscar-nominated movie Hidden Figures. Johnson also nurtured a love of knowledge throughout her life, earning an honorary doctorate degree from West Virginia University more than 75 years after dropping out of graduate school.

Johnson died on the morning of Monday, February 24, NASA administrator Jim Bridenstine shared on Twitter. He said in the announcement, "She was an American hero and her pioneering legacy will never be forgotten."

[h/t The New York Times]

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