Why Do We Yawn?
Everyone yawns, but no one knows why. We start when we are in the womb, and we do it through old age, but the purpose and survival value of yawning remain a mystery.
There is no shortage of theories but a dearth of experimental proof that any of them is correct. "The lack of experimental evidence is sometimes accompanied by passionate discussion," said Dr. Adrian G. Guggisberg, the lead author. Hippocrates proposed in the fourth century B.C. that yawning got rid of "bad air," and increased "good air" in the brain. The widely held modern view of this theory is that yawning helps increase blood oxygen levels and decrease carbon dioxide. If this were true, Dr. Guggisberg writes, then people would yawn more when they exercise. And people with lung or heart disease, who often suffer from a lack of oxygen, yawn no more than anyone else.
Our experience of time may be blinding us to its true nature, say scientists.
- Time may not be passing at all, says the Block Universe Theory.
- Time travel may be possible.
- Your perception of time is likely relative to you and limited.
From questionable shipwrecks to outright attacks, they clearly don't want to be bothered.
- Many have tried to contact the Sentinelese, to write about them, or otherwise.
- But the inhabitants of the 23 square mile island in the Bay of Bengal don't want anything to do with the outside world.
- Their numbers are unknown, but either 40 or 500 remain.
At least he wasn't burned at the stake, right?
- The letter suggests Galileo censored himself a bit in order to fly more under the radar. It didn't work, though.
- The Royal Society Journal will publish the variants of the letters shortly, and scholars will begin to analyze the results.
- The letter was in obscurity for hundreds of years in Royal Society Library in London.
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