Saturday, 4 October 2014
20 Things You Didn't Know About... Noise
20 Things You Didn't Know About... Noise
Did you know the Big Bang was noiseless?
By Jonathon Keats|Friday, May 23, 2014
1.
The Big Bang was noiseless. Everything in the universe expanded
uniformly, so nothing came into contact with anything else. No contact,
no sound waves.
2. Astronomer Fred Hoyle coined the term Big Bang in the ’50s, not because he thought it was noisy, but because he thought the theory was ridiculous.
3. For a really big bang, you should have
heard Krakatoa in 1883. On Aug. 27, the volcanic island in Indonesia
erupted with the explosive power of 200 megatons of TNT. The eruption
could be heard nearly 3,000 miles away, making it the loudest noise in
recorded history.
4. There are people who would outdo it if
they could. They pack their cars with stereo amps to pump out 180-plus
decibels (dB) of noise at so-called dB drag races. That’s how loud a jet
engine would sound — if it were a foot away from your ear.
5. Jets get a bad rap. According to
psychoacoustician Hugo Fastl, people perceive airplane noise as if it
were 10 dB greater than the equivalent noise made by a train.
6. Since the decibel scale is
logarithmic, growing exponentially, that means a jet sounds 10 times
noisier than a train when the noise levels of both vehicles are
objectively the same.
7. The only difference is that people
find plane noises more annoying. The effects are dubbed the “railway
bonus” and “aircraft malus.”
8. The first known noise ordinance was
passed by the Greek province of Sybaris in the sixth century B.C.
Tinsmiths and roosters were required to live outside the town limits.
9. Recognizing noise exposure as an
occupational safety hazard took longer. The first scientific study was
initiated in 1886 by Glasgow surgeon Thomas Barr. After he tested the
hearing of 100 boilermakers, he determined that incessant pounding of
hammers against metal boilers caused severe hearing loss.
10. One of Barr’s solutions to the
problem of “boilermaker’s ear” was to suggest that clergymen shave their
beards so that workmen could lip-read their sermons.
11. No wonder unprotected boilermaking
was a problem: The human ear can perceive sound waves that move the
eardrum less than the width of an atom.
12. You can fight noise with noise. The
first patent on “active noise cancellation” dates to 1933, when German
physicist Paul Lueg proposed to silence sound waves by simultaneously
generating waves of the exact opposite orientation. The principle is now
used in noise-canceling headsets.
13. Bring yours to the bar. Researchers
at the Université de Bretagne-Sud have found that men imbibe more than
20 percent faster when ambient noise is cranked up from 72 to 88 dB.
14. And people are only getting louder.
According to the World Forum for Acoustic Ecology, the volume of an
animated conversation between Americans increased by 10 dB during the
’90s.
15. Social and ambient noise causes
hearing loss, often misdiagnosed as an effect of aging. Preventing it
would require that cities become 10 dB quieter.
16. Deafness isn’t the only medical
danger of noise exposure. The stress causes some 45,000 fatal heart
attacks a year in the developing world, according to researcher Dieter
Schwela of the Stockholm Environment Institute.
17. And then there’s the unintended
assault on ocean dwellers by noisy navy sonar. The disorienting sound
drives beaked whales to beach themselves, and it makes humpbacks extend
the length of their songs by 29 percent.
18. To carry the same amount of
information in a noisier environment, the whale songs have become more
repetitive. Noise can be the nemesis of any signal.
19. Except when noise is the
signal. Back in the ’60s, Bell Labs astronomers Arno Penzias and Robert
Wilson kept picking up static with their radio telescope. They
eventually realized that the noise was the sound of the universe itself,
a remnant of a dense, hot plasma that pervaded the early cosmos.
20. Their discovery of the cosmic
microwave background radiation won them the Nobel Prize because the
remnant heat showed that the universe must have begun with a violent
explosion. Sorry, Fred Hoyle. The Big Bang is proven.
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