Wonders of Science: Our glorious age of (dis)information

Eric dons protective sunglasses to gaze into blue sky and ask, “Why is the sun…white?” Photo credit: Kelsey Rasmussen

by Eric Rasmussen

It is easy to take for granted how remarkable it is to have so much information available at our fingertips via our smartphones. Think about it for a second. The phones we are holding are about 300 times more powerful than the computers used to land Apollo astronauts on the moon. With these devices, we can access the entirety of human knowledge with a few clicks and swipes.

Heck, we are close to the point where we do not even have to type anything. If we have a question, we can just say a keyword like “Hey, Siri” and we get a response.

However, as the adage goes, with great power comes great responsibility.

Going hand in hand with the information age is also the disinformation age. The internet is one part informative, one part misleading and one part cat memes. This article provides a random grab bag of various scientific falsehoods and misconceptions widely seen and shared across the internet.

The sun is a yellow star

We see this all the time. In drawings, animated shows, web content, educational books. Almost anywhere we turn, our sun always is portrayed as yellow.

In reality, stars can be one of three colors: red, white and blue. Now, this is not because the universe is insanely patriotic, but because the color of stars is directly related to their surface temperature due to a physics phenomenon known as black-body radiation.

Black-body radiation describes the relationship between the color of an object and its surface temperature. Cool objects shed heat in the infrared portion of the light spectrum. Humans represent one such object, which is why our bodies glow like light bulbs when on infrared cameras.

As objects warm up, the light given off slowly shifts from infrared light to visible red light. Warmer still objects become white. Crank the temperature all the way up, and objects glow blue.

A star’s surface temperature is dependent on how massive it is. Small stars have low surface temperatures, whereas the largest stars have the highest surface temperatures. Our sun is on the smaller side with a surface temperature of 10,000 degrees Fahrenheit. This results in its white coloration.

 

The sky is blue

The popular childhood question, “Why is the sky blue?” is a great one. But it is also the wrong question. Better to ask, “Why does the sky change colors?”

When the sun is close to the horizon, the sky will look orange. But when the sun is overhead, the sky looks a fantastic blue. What is going on here?  The answer comes down to a concept known as Rayleigh Scattering.

First off, remember the white light from our sun is actually composed of all the colors of the rainbow. This fact becomes evident when light interacts with water or glass and is separated into its spectrum of colors. Earth’s atmosphere, composed of billions and billions of molecules of oxygen, carbon dioxide, nitrogen, etc., interacts with light the same way.

When light from the sun streams into Earth’s atmosphere, it hits these molecules and scatters like billiard balls. Blue light is affected the most by this process.

When the sun glows directly overhead, blue light scatters equally in all directions. This is why no matter where we look, the atmosphere will appear blue. However, when the sun is close to the horizon during a sunrise or sunset, its light actually has to travel a longer distance through the atmosphere. This longer path allows orange and red light to scatter alongside blue light, which results in the atmosphere taking on fantastic colorations. These same physics also cause our white sun to appear yellow.

What goes up must come down

Astronauts are not weightless because they left Earth’s gravity; rather, they are simply falling toward Earth at the same rate Earth is curving away. Image Credit: Cannon = http://www.pas.rochester.edu/~blackman/ast104/cannon.gif

Yes, for everyday experiences this statement appears correct. Throw an object into the air, wait a moment, and down it comes. This phenomenon is especially important for the opening kickoff to a football game, which otherwise would be most anticlimactic. “Here we go, the game has started…and it’s over,” as we watch the football sail into the cosmos.

However, imagine let us imagine we have a line of kickers and each one is stronger than the last. The first kicker kicks a ball, and it lands 10 feet away. The next one kicks the ball, and it lands 80 feet away, 100 feet away, 1,000 feet away, 20 miles away. Eventually, we might have a kicker who lambastes a football so hard it never lands. Instead, the ball keeps orbiting the Earth. Why? Because the ball is now falling at the same rate the Earth is curving away.

This particular speed is called orbital speed, and for Earth that velocity is about 67,000 miles per hour.  The next time the International Space Station goes by, let us look up and consider that the astronauts on board are traveling at orbital speed, and that is why they are in orbit. Astronauts are not weightless because they left Earth’s gravity; rather, they are simply falling toward Earth at the same rate Earth is curving away.

 

Calories do not count on a birthday

This is 100 percent true. Anyone who says otherwise is lying.

 

 

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