8 Things You’ve Always Wondered, Answered

Because knowledge is power!

1. What is déjà vu?

When you experience déjà vu, your brain is creating an illusion — thought to be derived from a miscommunication between two parts of the brain. Within our brains is the hippocampus, which is responsible for storing our short-term memories. When our hippocampus is activated, it may cause memory experiences like déjà vu.

2. Can you get COVID-19 from receiving a COVID-19 vaccination?

Because none of the COVID-19 vaccines in the United States contain the live virus that causes COVID-19, the vaccine itself cannot cause COVID-19. In fact, evidence suggests that COVID-19 vaccines can help protect people against COVID-19 which can cause serious illness and hospitalization.

3. If outer space is black, why is our sky blue?

The true answer for this one is quite complex, but in essence, there is no atmosphere in space to scatter light, which ultimately affects the way we perceive colors. Our atmosphere acts as a prism, which breaks light into an array of different colors due to their different wavelengths. This phenomenon also explains why the sunrise and sunset illuminate the sky with reds and oranges —the lower angle of the sun causes this change in colors, as the only colors that remain visible after passing through such a thick amount of our atmosphere are reds and oranges. 

4. Do dogs see only in black and white?

The idea that dogs perceive only black and white color is actually a myth with a more nuanced reality. In all animals, the spectrum of what we see is determined by color-detecting molecules in the eye called photoreceptors. Dogs see a color spectrum ranging from shades of yellow to shades of blue. Although our canine friends have a more limited perception of color, they do win against humans with their night vision, as their eyes contain more rods than ours do.

5. Can you really catch a virus from cold weather?

There are both truths and misconceptions contained in this old adage. Ultimately, the cold itself does not tend to cause sickness. However, viruses may survive more easily in winter's cold, dry air. Colder weather also tends to keep people indoors, which allows viruses to spread between people with greater ease. 

6. Why does metal ruin a microwave?

Ultimately, a metal object placed inside a microwave oven would deflect a microwave's electromagnetic radiation away from the food within it. It would then cause these waves to jump around erratically, possibly damaging the interior of the oven.

7. Does gum stay in your digestive tract for seven years?

Although gum is very much made to be chewed rather than swallowed, it generally isn't harmful if the latter occurs. It is true that gum moves through our bodies undigested, but it doesn't remain there for seven years. Ultimately, swallowed gum will be excreted through stool, relatively intact (but intentionally swallowing gum is not recommended).

8. Why do we need new vaccinations as time progresses?

As a virus spreads, it has more opportunities to mutate, or change its genetic makeup. These new variants of a virus may mean our defense systems need an update. mRNA COVID-19 vaccines work by introducing a piece of mRNA that corresponds to the virus's specific makeup. This enables our bodies to recognize that the protein is foreign and produce an immune response to help protect against COVID-19.

Imagery via Getty

To learn more about COVID-19 and a vaccine option for you, visit CDC's vaccines.gov today.