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How Can a Butterfly, Weighing No More Than a Feather, Fly Into the Wind?

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This question, from our brilliant reader Greg, is actually rather poetic, isn't it? It's so wonderful that I want to write it out again:

How can a butterfly, weighing no more than a feather, fly into the wind?

Ahh, that felt good. Okay, to the question. How is this possible? How can a butterfly, so slight, with its wings made seemingly of lace, take to lapis summer skies in the face of buffeting winds?

O Hark! Butterfly, fluttering
Between the Earth and heaven
Against the cool, slippery hand
Of wind's wanton wail

Ack, sorry again. Got carried away. Right. Butterflies. Wind. How does it happen? We contacted Professor Robert Dudley, head of the Animal Flight Laboratory at U.C. Berkeley to find out. He says that, no matter the animal, if wind speed exceeds maximum flight speed, then it can't fly. Different species of butterflies fly at different speeds, and the range is about 1.5 to 10 meters per second (~3 to 23 miles per hour). If the windspeed is any higher than that, then the butterfly isn't slipping the surly bounds of Earth to cut through it.

Professor Dudley also says that many small butterflies avoid high winds as they would merely drift. A butterfly's wing is more suceptible to ambient winds, so, while capable of flying into the wind, they aren't exactly engineered for it.

That ain't poetry, it's science.

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

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Big Questions
Do Cats Fart?
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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.

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