Whenever someone strikes up a conversation with me about the universe, I get animated.
No surprise there: I’ve made a living writing about astronomy, physics, geology, spaceflight, and related areas of science for nearly a decade, and have read obsessively on these topics for much longer than that.
However, people have shared a lot of peculiar “facts” with me over the years that ended up being totally false.
Below are some of the silliest and most common claims I’ve heard.
No one is perfect — I believed many of these statements at some point in my life — but it’s time to put these myths, misconceptions, and inaccuracies to rest.
MYTH: The sun is yellow.
If you wince and look at the afternoon sun, it might look yellow — but the light it gives off is actually white in color.
The Earth’s atmosphere between your eyes and the sun is what makes the star appear yellow.
The gases bend the light in an effect called Rayleigh scattering, which is what also makes the sky appear blue and causes sunsets to blaze into brilliant oranges and reds.
Not helping matters is that astronomers classify the sun as a yellow main-sequence G-type star, or “yellow dwarf.”
MYTH: The Sahara is the biggest desert on Earth.
Not all deserts are hot and full of sand. They need only be dry and inhospitable.
Antarctica fits the bill, since it receives only two inches of precipitation a year and has few land animals.
At 5.4 million square miles compared to the Sahara’s 3.6 million square miles, the Bottom of the World is a vastly larger desert.
MYTH: Astrology can predict your personality or the future.
Wouldn’t it be nice to get a glimpse of tomorrow based on something as simple as where the sun, planets, and moon were located when you were born?
That’s what astrology claims to do, what 50% the world at least partly believes, and what as much as 2% of the planet strongly buys into.
Yet thorough scientific investigations of astrology have failed, again and again, to back up any predictions from an astrological sign or horoscope.
A 1985 study in Nature is especially notable. In that experiment, scientists used a non-biased, double-blind protocol and worked in conjunction with some of the top astrologers in the US to test the predictive power of astrological signs.
The results? The astrological predictions were no better than chance.
Sources: The Humanist, Comprehensive Psychology, Nature, Proceedings of the Biennial Meeting of the Philosophy of Science Association, Pseudoscience and Deception: The Smoke and Mirrors of Paranormal Claims,
MYTH: When you call someone, the signal bounces off a satellite.
This is true of satellite phones, which the military uses every day, but your mobile phone works in a much different way.
Mobile phones broadcast a wireless radio signal and constantly look for, ping, and relay data to and from land-based cellular towers.
When you make a call, the nearest tower connects you to another phone via a vast network of tower-to-tower connections and buried cables.
At best, a satellite might be involved in a call around the globe — but 99% of international communications data travels through undersea cables.
MYTH: The Great Wall of China is the only man-made structure visible from space.
The Great Wall of China isn’t the only man-made structure visible from space.
It all depends on where you believe space begins above Earth.
From the International Space Station, 250 miles up, you can see the wall and many other man-made structures. From the moon, you can’t see any structures at all — only a dim glow of city lights.
MYTH: The moon’s gravity pulling on water causes the tides.
This is only partly true.
The moon does pull on ocean water, but that tug at any one point is about 10 million times weaker than Earth’s gravity. It’s really the interplay of gravity between the moon, Earth, and sun that creates a tidal force, and it’s more of a “push” than a “pull.”
Each molecule of water is pulled by the moon’s gravity, but alone that acceleration is so weak it isn’t noticeable. Because ocean water covers about 71% of Earth’s surface and is connected as one liquid body, however, all of those tiny tugs add up to form a significant pressure — the tidal force.
Molecules of water near the poles are pulled mostly straight down, those on the face of Earth closest to the moon experience the strongest pull toward the moon, and those on the opposite side of Earth feel the weakest acceleration.
Together, these interactions form a pressure on seawater that generally directs it away from the poles and toward the equator, where it’s strong enough to fight gravity to form two bulges: the high tides.
Tides follow the moon as it orbits Earth every 28 days, but it’s not as simple as that. Water sloshes around, just as it does within in aquarium, and the shape of the seafloor, the position of the coasts, and the Coriolis effect (caused by Earth’s rotation) affect where and to what extent tides occur — resulting in a complex pattern of “tidal nodes.”
“Earth rotates so quickly that the tide water wave can’t move around the Earth quickly enough,” Ted Swift, an environmental scientist who works for the state of California, told Business Insider in an email. “What we see as tides on the coast are resonances — rotating standing waves — set up by the fundamental tidal potential ‘signal.'”
Smaller bodies of water, like lakes and pools, don’t have noticeable tides because they lack enough liquid to create a pressure that can visibly overcome the pull of Earth’s gravity.
The sun’s gravity also affects the tides, accounting for roughly one-third of the phenomenon. When the sun’s gravity counteracts the moon’s, it leads to lower-than-average “neap tides.” When the sun lines up with the moon, it triggers larger “spring tides.”
Correction: An earlier version of this article mischaracterized the nature of tides.
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