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.

What Did the Hubble Telescope See on Your Birthday? This NASA Website Will Show You

A 2010 Hubble-captured image of a pillar of gas and dust in a stellar nursery called Carina Nebula.
A 2010 Hubble-captured image of a pillar of gas and dust in a stellar nursery called Carina Nebula.

The Hubble Space Telescope was launched into orbit on April 24, 1990, and it has spent the last three decades enriching our understanding of the cosmos more than we ever could’ve imagined. This year, NASA is celebrating the telescope's 30th birthday with another launch: a website that shows you a photo of what the Hubble saw on your birthday.

Because the telescope is exploring space every hour of every day, the images it has captured over the years are both fascinating and varied. You could see a globular star cluster, a dust storm on Mars, or something else entirely. You only need to enter the date and month of your birthday on the site, so the image you get won’t necessarily be from the year you were born—and, if you were born before 1990, it definitely won’t be—but it’s pretty fun to juxtapose how you were spending that particular birthday with how the Hubble was spending it. While your parents were snapping a shot of you blowing out the candles at your eighth birthday party, for example, the Hubble might’ve been snapping a shot of the beautiful auroras around Jupiter’s north pole.

The telescope was first conceived all the way back in 1946 by Yale University astrophysicist Lyman Spitzer, Jr., who published a paper about the possible advantages of having what he called a “large space telescope” in orbit to help astronomers study the galaxies. The project finally got off the ground in the 1970s, and the telescope was designed so that astronauts could periodically upgrade it while still in orbit. Since it first broke through the atmosphere in 1990, the Hubble—named after astronomer Edwin Hubble, who proved the existence of other galaxies beyond the Milky Way—has taught us that the universe is 14 billion years old, that its expansion is speeding up, and so much more.

Unlock your birthday image on the Hubble website here, and check out more stellar photos taken by the Hubble here.

Mark Your Calendars: The Lyrid Meteor Shower Is Coming

Daniel Reinhardt, Getty Images
Daniel Reinhardt, Getty Images

If you've grown tired of Zoom meetings, Netflix parties, and livestreams, take a break from staring at your screens to look up at the sky. Starting in April, the Lyrid meteor shower will make its annual appearance. Here's what you need to know to see the spectacle from wherever you're quarantined.

What are the Lyrids?

With written evidence of the event dating back to China around 690 BCE, the Lyrids are one of the oldest meteor showers on record. The light show occurs when our planet passes through the tail of the comet C/1861 G1 Thatcher, causing its rocky debris to burn up in the atmosphere.

From Earth, the Lyrids appear to originate from the constellation Lyra, which rises above the northeastern horizon after dusk, and the meteor shower borrows its name from the constellation. The Lyrids aren't as active as some other annual showers, usually maxing out at just 20 shooting stars per hour on peak nights. But patient spectators are sometimes rewarded: The event has been known to have outbursts of up to 100 meteors in a single hour. Such surges are rare and random, so all sky-gazers can do is look up at peak times and hope to get lucky.

How to See the Lyrid Meteor Shower

The Lyrids start every year around April 16, but your best chance at seeing them comes later in the month. Late April 21 through early April 22, the meteor shower is predicted to reach peak activity. Following that period, the shooting stars from the shower will become less frequent before finally fizzling out around April 25.

The Lyrids may be easier to spot in 2020 than in recent years. Since businesses closed and people started sheltering in their homes, there has been a slight dip in light and air pollution. Those darker, clearer skies will create better conditions for spotting shooting stars in some parts of the country. As always, waiting until skies are darkest—in the hours around midnight, typically—is the best way to boost your chances of seeing as many meteors as possible.

SECTIONS

arrow
LIVE SMARTER