10 Misconceptions About Space

People have a lot of weird misconceptions about space (thanks, Hollywood). Here are a few myths about the universe and their real explanations—and we hope you like NASA, because they're going to come up a lot.

1. The Sun is on fire.

Artist's rendering of the sun
iStock/mrtom-uk

When some people picture the Sun, they imagine something like a campfire or an object on fire. But the Sun is actually a ball of gas. It burns thanks to nuclear fusion, which happens in its core. Every second, 700 million tons of hydrogen gets converted into 695 million tons of helium. When this happens, energy is released as gamma rays, which get converted to light. So, the Sun emits light and heat, but it's not on fire, because there's no oxygen involved.

2. The Sun is the only star that has planets.

Jupiter and Mars in the solar system
iStock/themotioncloud

Experts now believe that most of the stars in our Milky Way have planets surrounding them. Any planet that's found outside of our solar system is known as an exoplanet, and we can be pretty sure that they exist because they affect the way a star appears. One of the most common ways to detect exoplanets is to look for a decrease in light from certain stars at various times, which would indicate that a planet is passing in front of the star, affecting how the light appears to us.

3. Mercury is the closest planet to the Sun, so it's the hottest.

Colorized image of Venus's clouds
NASA/JPL // Public Domain

Distance from the Sun actually has little to do with the average temperature on a planet. Venus (the second planet from the Sun) is the hottest planet in the solar system, but that's because of its atmosphere, which contains mostly carbon dioxide and some nitrogen, making it very thick. Throughout the year the surface of Venus remains at a temperature of about 462°C. The surface of Mercury, on the other hand, has a lot of temperature variations. It can be as cold as -173°C at night, and during the day it might reach 427°C. Mercury has a very thin atmosphere, which is why there's so much variation in temperature.

4. People explode in space.

NASA astronaut performing a spacewalk
NASA/JSC // Public Domain

Space is a near-vacuum, which means that people can't survive out there for more than a few minutes—but exploding isn't a concern. A body exposed in space will expand and bloat, especially the air in the lungs and the water in body tissue, but human skin is actually tight enough to prevent exploding. A person exposed to space would eventually die when circulation stops, after dissolved gases in the blood form bubbles and block flow. Basically, it's like an extreme version of "the bends" that divers can get.

5. In the 1960s, NASA spent millions developing a pen that would write in space.

NASA astronaut writing with a space pen
NASA/JSC // Public Domain

This is a popular myth on the internet—and even in one episode of The West Wing. People tend to use this as a comparison between NASA and Soviet astronauts, who were smart enough to just bring pencils. But NASA used pencils as well, and they have the receipts to prove it. In 1965, NASA placed an order for 34 mechanical pencils from Houston's Tycam Engineering Manufacturing Incorporated. There was an independent company, the Fisher Pen Company, that developed a space pen for around $1 million. And later, both NASA and the Soviets started using Fisher's anti-gravity space pen (it was a great pen).

6. In space, you experience zero gravity.

NASA astronauts experiencing decreased gravity
NASA/JSC // Public Domain">NASA/JSC // Public Domain

Gravity is considered the most important force in the universe, and it doesn't just go away when we leave Earth. Gravity is necessary for everything from the Moon's ability to orbit the Earth to the Sun staying put in the Milky Way. What astronauts actually experience in space is what NASA calls micro-gravity. It has nothing to do with the actual strength of gravity, which is only very slightly less on the International Space Station. It's because astronauts are constantly falling, so they seem weightless.

7. Black holes are like vacuums.

As we learn more and more about black holes, experts are more likely to compare them to Venus flytraps than vacuums. Black holes don't suck up everything nearby; instead, they sit pretty dormant, then if a star approaches it and gets too close, the black hole becomes active. And still, only some of the objects nearby get ripped apart by the black hole.

8. The Moon orbits Earth once a day.

Earth's moon
NASA/JPL/USGS // Public Domain

It takes about 27.3 days for the Moon to orbit Earth. This is known as a sidereal month. It's worth noting that the Moon's orbit isn't considered regular—it has variations, and there are upwards of five different months that astronomers recognize.

9. There's a dark side of the Moon.

Earth's Moon from the International Space Station
NASA/JSC // Public Domain

As the Moon is orbiting Earth, it's also rotating on its axis, so we're always seeing the same side of the Moon. But the opposite side isn't dark: it gets the same amount of sunlight as the other side.

10. A light-year measures time.

It actually measures distance. NASA defines a light-year as "the total distance that a beam of light, moving in a straight line, travels in one year." Light travels at around 300,000 kilometers per second, so a light-year is around 10 trillion (10,000,000,000,000) kilometers.

Be sure to subscribe here for more Mental Floss videos.

This story was republished in 2019.

Amazon's Under-the-Radar Coupon Page Features Deals on Home Goods, Electronics, and Groceries

Stock Catalog, Flickr // CC BY 2.0
Stock Catalog, Flickr // CC BY 2.0

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Now that Prime Day is over, and with Black Friday and Cyber Monday still a few weeks away, online deals may seem harder to come by. And while it can be a hassle to scour the internet for promo codes, buy-one-get-one deals, and flash sales, Amazon actually has an extensive coupon page you might not know about that features deals to look through every day.

As pointed out by People, the coupon page breaks deals down by categories, like electronics, home & kitchen, and groceries (the coupons even work with SNAP benefits). Since most of the deals revolve around the essentials, it's easy to stock up on items like Cottonelle toilet paper, Tide Pods, Cascade dishwasher detergent, and a 50 pack of surgical masks whenever you're running low.

But the low prices don't just stop at necessities. If you’re looking for the best deal on headphones, all you have to do is go to the electronics coupon page and it will bring up a deal on these COWIN E7 PRO noise-canceling headphones, which are now $80, thanks to a $10 coupon you could have missed.

Alternatively, if you are looking for deals on specific brands, you can search for their coupons from the page. So if you've had your eye on the Homall S-Racer gaming chair, you’ll find there's currently a coupon that saves you 5 percent, thanks to a simple search.

To discover all the deals you have been missing out on, head over to the Amazon Coupons page.

Sign Up Today: Get exclusive deals, product news, reviews, and more with the Mental Floss Smart Shopping newsletter!

How Do Astronauts Vote From Space?

Astronaut Kate Rubins casts her ballot from space.
Astronaut Kate Rubins casts her ballot from space.
NASA

Earlier this week, NASA announced that astronaut Kate Rubins had officially cast her vote from a makeshift voting booth aboard the International Space Station. As much as we’d like to believe her ballot came back to Earth in a tiny rocket, the actual transmission was much more mundane. Basically, it got sent to her county clerk as a PDF.

As NASA explains, voting from space begins the same way as voting abroad. Astronauts, like military members and other American citizens living overseas, must first submit a Federal Postcard Application (FPCA) to request an absentee ballot. Once approved, they can blast off knowing that their ballot will soon follow.

After the astronaut’s county clerk completes a practice round with folks at the Johnson Space Center in Houston, they can start the real voting process. The astronaut will then receive two electronic documents: a password-protected ballot sent by the Space Center’s mission control center, and an email with the password sent by the county clerk. The astronaut then “downlinks” (sends via satellite signal) their filled-out ballot back to the Space Center attendants, who forward it to the county clerk. Since the clerk needs a password to open the ballot, they’re the only other person who sees the astronaut’s responses. Then, as NPR reports, they copy the votes onto a regular paper ballot and submit it with the rest of them.

Though Americans have been visiting space for more than half a century, the early jaunts weren’t long enough to necessitate setting up a voting system from orbit. That changed in 1996, when John Blaha missed out on voting in the general election because his spaceflight to Russia’s space station Mir began in September—before absentee voters received their ballots—and he didn’t return until January 1997. So, as The Washington Post reports, NASA officials collaborated with Texas government officials to pass a law allowing astronauts to cast their ballots from space. In the fall of 1997, David Wolf became the first astronaut to submit his vote from a space station. The law is specific to Texas because most active astronauts reside there, but NASA has said that the process can be done from other states if need be.