Original image

Whatever Happened to the Hole in the Ozone Layer?

Original image

Image credit: NASA

Let's start with the bad news: Remember that hole in the ozone layer that scientists discovered over the Antarctic in 1985? The one we worried would give us all skin cancer and cataracts with its unshielded bursts of UV rays? It’s still there.

It gets worse. Scientists announced that a new hole opened up in early 2011—this one over the Arctic. So it’s still a rough time for the stratosphere, the layer of the atmosphere that helps block out some of the sun’s UV rays.

But here’s the good news: we’ve got a handle on the problem.

When the first hole came to light, world leaders moved quickly. Through the Montreal Protocol of 1987, several nations nixed the production of ozone-killing chlorofluorocarbons. Saving the ozone was literally the first thing the whole world ever agreed on: A treaty banning CFCs was the first agreement ever to be ratified by every country in the United Nations.

As the level of atmospheric CFCs began to drop, the ozone layer started repairing itself. While the going is slow—a lot of the CFCs we released in the 1970s and 80s are still floating around doing damage—scientists hope the ozone layer will be back to normal by the end of this century.

Oddly enough, the depleted ozone layer did have one positive side effect: It helped curb global warming. The thinned ozone of the Antarctic led to brighter clouds that reflected some of the sun’s radiation away from Earth. Cutting out this effect may give global warming a slight boost, but scientists are quick to note that we’re far better off with a healthy ozone layer.

This article originally appeared in the Jan-Feb 2012 issue of mental_floss magazine.

Original image
Big Questions
What Is the Difference Between Generic and Name Brand Ibuprofen?
Original image

What is the difference between generic ibuprofen vs. name brands?

Yali Friedman:

I just published a paper that answers this question: Are Generic Drugs Less Safe than their Branded Equivalents?

Here’s the tl;dr version:

Generic drugs are versions of drugs made by companies other than the company which originally developed the drug.

To gain FDA approval, a generic drug must:

  • Contain the same active ingredients as the innovator drug (inactive ingredients may vary)
  • Be identical in strength, dosage form, and route of administration
  • Have the same use indications
  • Be bioequivalent
  • Meet the same batch requirements for identity, strength, purity, and quality
  • Be manufactured under the same strict standards of FDA's good manufacturing practice regulations required for innovator products

I hope you found this answer useful. Feel free to reach out at For more on generic drugs, you can see our resources and whitepapers at Pharmaceutical strategic guidance and whitepapers

This post originally appeared on Quora. Click here to view.

Original image
Big Questions
Do Cats Fart?
Original image

Certain philosophical questions can invade even the most disciplined of minds. Do aliens exist? Can a soul ever be measured? Do cats fart?

While the latter may not have weighed heavily on some of history’s great brains, it’s certainly no less deserving of an answer. And in contrast to existential queries, there’s a pretty definitive response: Yes, they do. We just don’t really hear it.

According to veterinarians who have realized their job sometimes involves answering inane questions about animals passing gas, cats have all the biological hardware necessary for a fart: a gastrointestinal system and an anus. When excess air builds up as a result of gulping breaths or gut bacteria, a pungent cloud will be released from their rear ends. Smell a kitten’s butt sometime and you’ll walk away convinced that cats fart.

The discretion, or lack of audible farts, is probably due to the fact that cats don’t gulp their food like dogs do, leading to less air accumulating in their digestive tract.

So, yes, cats do fart. But they do it with the same grace and stealth they use to approach everything else. Think about that the next time you blame the dog.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at


More from mental floss studios