6 ms·

A Sound So Loud That It Circled the Earth Four Times (2014)

184 points by dnetesn 8y ago

se7entime 8y ago
"ACTNews, PANDEGLANG – Tsunami hit coastal areas around Sunda Strait in Pandeglang, Serang, and South Lampung Regencies. The disaster happened on Saturday (12/22) at 9:27 p.m., Indonesian Bureau of Meteorology Climatology and Geophysics (BMKG) predicted that the massive wave was caused by underwater flank collapse after the eruption of Anak Krakatau Mountain as well as the tidal force caused by the full moon." - https://act.id/en/news/detail/tsunami-hit-pandeglang-serang-and-south-lampung https://act.id/en/news/detail/tsunami-hit-pandeglang-serang-... "Anak" = Children/Child of The Death Toll has reached 373 people, 1.459 wounded and 128 still missing https://www.bnpb.go.id/en/tim-sar-gabungan-terus-menemukan-korban-tsunami-selat-sunda-373-meninggal-dunia-1459-luka-luka-dan-128-hilang https://www.bnpb.go.id/en/tim-sar-gabungan-terus-menemukan-k...
- jiveturkey 8y ago
  are you saying that the sound of this recent eruption was also heard 'round the world?
- NegativeLatency 8y ago
  > the tidal force caused by the full moon. Is that real? Doesn’t seem like it would matter enough. Especially when there was an eruption, why even mention it.
  - goodcanadian 8y ago
    Yes, it's real. Tides are higher around the full moon due to the earth, sun, and moon being (roughly) aligned. If it was already high tide, adding a tsunami on top of it is going to be more impactful than at low tide.
TekMol 8y ago
Does a sound ever stop?
- zaarn 8y ago
  Yes, once it's kinetic energy drops below that of the average air molecule, it'll become imperceptible to instruments; lost in the noise, or rather, becoming part of the noise.
  - jacquesm 8y ago
    Interesting. Besides 'Brownian' noise you are probably correct that whatever noise remains is to some extent the result of a lot of stuff that happened in the past that is too small now in influence to be identified. I never looked at it that way, thank you.
    - Pyxl101 8y ago
      Specifically, the energy that is sound will gradually dissipate into energy that is heat. Brownian motion happens on the microscopic level; we perceive it on the macroscopic level as temperature. Temperature is essentially the combined, average kinetic energy of Brownian motion. Most types of energy gradually turn into heat, including light, macroscopic kinetic energy, released gravitational potential energy, etc. If you catch a baseball, the kinetic energy of the baseball turns into heat within your muscles (and skin, in the form of friction between the ball and your hands). If you walk down stairs, the gravitational potential energy that you're releasing turns into heat as well, as friction in your joints. Light shining on your skin turns into heat and warms it, as on a bright and sunny day. The electrical energy of a computer converts largely into heat, hence the need for cooling. There are also theories that all matter may eventually decay, including all atoms and eventually even protons after 10^34 years (though proton decay has not yet been experimentally observed). https://en.wikipedia.org/wiki/Proton_decay https://en.wikipedia.org/wiki/Proton_decay As someone on Quora wrote, "Heat is energy's final grave". The concept of "heat death of the universe" derives from the idea that, eventually, most forms of energy will decay into heat.
vxNsr 8y ago
This is just insane!! that video where the sound takes 13 seconds to reach the camera really helps cement the point of the article.
- andyidsinga 8y ago
  I think I watched that video 15 times ... at 4.4km / 2.7miles away those must be larger-than-house sized chunks of rock falling ! (clearly visible to the left of the explosion).
bitcurious 8y ago
The explosion of Krakatoa is believed by some scholars to be the inspiration for Edvard Munch's painting "The Scream." https://www.skyandtelescope.com/press-releases/astronomical-sleuths-link-krakatoa-to-edvard-munchs-painting-the-scream/ https://www.skyandtelescope.com/press-releases/astronomical-...
- Insanity 8y ago
  That was interesting to read as well :) Might deserve it's own post on HN imo!
red_admiral 8y ago
I've read in other sources that the force of the main eruption in 1883 was equivalent to around 100 megatons of TNT. The dust that it ejected into the atmosphere was not only the cause of the bright sunsets that inspired artists in Europe over the next few years, but also caused a global cooling by something like 1 degree (Celsius) for the next two years.
- techsin101 8y ago
  So we can solve global warming?
  - smitty1110 8y ago
    It was a temporary measure, and the only volcano I know that would significantly move the needle is Yellowstone. And I really, really don’t want that to go off while I’m still alive, I like North America when it’s not covered in ash.
  - danohuiginn 8y ago
    Nuclear Winter is technically a solution to global warming, I guess
moioci 8y ago
Just to put a plug in for Simon Winchester's book, Krakatoa: the Day the World Exploded. If anyone wants to dive deeper in this topic.
rexarex 8y ago
This event led to the discovery of ‘infrasound’ or very low frequency sound that travels very long distances. It’s currently still used to detect (above ground) nuclear explosions as part of the Comprehensive Nuclear Test Ban Treaty (CTBT). There is a site in the ‘Windless Blight’ in Antarctica near McMurdo Station that a couple of techs go dig out and maintain every year. I believe there are about 30 around the world. https://www.ctbto.org/verification-regime/monitoring-technologies-how-they-work/infrasound-monitoring/ https://www.ctbto.org/verification-regime/monitoring-technol...
rcthompson 8y ago
I wonder whether the sound wave got stronger again as it reached the opposite side of the globe from the source. Would it have made it back into the audible range? Maybe not, since I imagine that intervening mountains and such would disrupt or change the speed of the waves.
edge17 8y ago
Regarding magnitude of these types of events, NOAA does amazing work collecting data on tsunami events with impressive energy simulations. As some point I had seen several videos from the Chile event in 2010 that showed the shockwaves traveling around the earth multiple times, but I can't seem to find those videos now. Here's a link to one of the videos with an energy plot from the Chile event - https://nctr.pmel.noaa.gov/chile20100227/20100227Chile.mov https://nctr.pmel.noaa.gov/chile20100227/20100227Chile.mov And the specific Chile event page - https://nctr.pmel.noaa.gov/chile20100227/weblink.html https://nctr.pmel.noaa.gov/chile20100227/weblink.html If you browse around the site, there is a lot of information for many of the largest earthquake/tsunami events in recent times.
- edge17 8y ago
  And a youtube link to some more forecast models from the Pacific Tsunami Warning Center's youtube channel https://www.youtube.com/playlist?list=PLd18vQxXt2zNmVDB2NQxV-lnkL2bZtlLQ https://www.youtube.com/playlist?list=PLd18vQxXt2zNmVDB2NQxV...
brian-armstrong 8y ago
This must be the article so interesting it landed on HN Front Page Four Times :)
andyidsinga 8y ago
my ears almost hurt reading this: > The British ship Norham Castle was 40 miles from Krakatoa at the time of the explosion. The ship’s captain wrote in his log, “So violent are the explosions that the ear-drums of over half my crew have been shattered. My last thoughts are with my dear wife. I am convinced that the Day of Judgement has come.”

184 points by dnetesn 8y ago

"ACTNews, PANDEGLANG – Tsunami hit coastal areas around Sunda Strait in Pandeglang, Serang, and South Lampung Regencies. The disaster happened on Saturday (12/22) at 9:27 p.m., Indonesian Bureau of Meteorology Climatology and Geophysics (BMKG) predicted that the massive wave was caused by underwater flank collapse after the eruption of Anak Krakatau Mountain as well as the tidal force caused by the full moon." - https://act.id/en/news/detail/tsunami-hit-pandeglang-serang-and-south-lampung https://act.id/en/news/detail/tsunami-hit-pandeglang-serang-... "Anak" = Children/Child of The Death Toll has reached 373 people, 1.459 wounded and 128 still missing https://www.bnpb.go.id/en/tim-sar-gabungan-terus-menemukan-korban-tsunami-selat-sunda-373-meninggal-dunia-1459-luka-luka-dan-128-hilang https://www.bnpb.go.id/en/tim-sar-gabungan-terus-menemukan-k...

jiveturkey 8y ago
are you saying that the sound of this recent eruption was also heard 'round the world?
NegativeLatency 8y ago
> the tidal force caused by the full moon. Is that real? Doesn’t seem like it would matter enough. Especially when there was an eruption, why even mention it.
- goodcanadian 8y ago
  Yes, it's real. Tides are higher around the full moon due to the earth, sun, and moon being (roughly) aligned. If it was already high tide, adding a tsunami on top of it is going to be more impactful than at low tide.

TekMol 8y ago

Does a sound ever stop?

zaarn 8y ago
Yes, once it's kinetic energy drops below that of the average air molecule, it'll become imperceptible to instruments; lost in the noise, or rather, becoming part of the noise.
- jacquesm 8y ago
  Interesting. Besides 'Brownian' noise you are probably correct that whatever noise remains is to some extent the result of a lot of stuff that happened in the past that is too small now in influence to be identified. I never looked at it that way, thank you.
  - Pyxl101 8y ago
    Specifically, the energy that is sound will gradually dissipate into energy that is heat. Brownian motion happens on the microscopic level; we perceive it on the macroscopic level as temperature. Temperature is essentially the combined, average kinetic energy of Brownian motion. Most types of energy gradually turn into heat, including light, macroscopic kinetic energy, released gravitational potential energy, etc. If you catch a baseball, the kinetic energy of the baseball turns into heat within your muscles (and skin, in the form of friction between the ball and your hands). If you walk down stairs, the gravitational potential energy that you're releasing turns into heat as well, as friction in your joints. Light shining on your skin turns into heat and warms it, as on a bright and sunny day. The electrical energy of a computer converts largely into heat, hence the need for cooling. There are also theories that all matter may eventually decay, including all atoms and eventually even protons after 10^34 years (though proton decay has not yet been experimentally observed). https://en.wikipedia.org/wiki/Proton_decay https://en.wikipedia.org/wiki/Proton_decay As someone on Quora wrote, "Heat is energy's final grave". The concept of "heat death of the universe" derives from the idea that, eventually, most forms of energy will decay into heat.

vxNsr 8y ago

This is just insane!! that video where the sound takes 13 seconds to reach the camera really helps cement the point of the article.

andyidsinga 8y ago
I think I watched that video 15 times ... at 4.4km / 2.7miles away those must be larger-than-house sized chunks of rock falling ! (clearly visible to the left of the explosion).

bitcurious 8y ago

The explosion of Krakatoa is believed by some scholars to be the inspiration for Edvard Munch's painting "The Scream." https://www.skyandtelescope.com/press-releases/astronomical-sleuths-link-krakatoa-to-edvard-munchs-painting-the-scream/ https://www.skyandtelescope.com/press-releases/astronomical-...

Insanity 8y ago
That was interesting to read as well :) Might deserve it's own post on HN imo!

red_admiral 8y ago

I've read in other sources that the force of the main eruption in 1883 was equivalent to around 100 megatons of TNT. The dust that it ejected into the atmosphere was not only the cause of the bright sunsets that inspired artists in Europe over the next few years, but also caused a global cooling by something like 1 degree (Celsius) for the next two years.

techsin101 8y ago
So we can solve global warming?
- smitty1110 8y ago
  It was a temporary measure, and the only volcano I know that would significantly move the needle is Yellowstone. And I really, really don’t want that to go off while I’m still alive, I like North America when it’s not covered in ash.
- danohuiginn 8y ago
  Nuclear Winter is technically a solution to global warming, I guess

moioci 8y ago

Just to put a plug in for Simon Winchester's book, Krakatoa: the Day the World Exploded. If anyone wants to dive deeper in this topic.

rexarex 8y ago

This event led to the discovery of ‘infrasound’ or very low frequency sound that travels very long distances. It’s currently still used to detect (above ground) nuclear explosions as part of the Comprehensive Nuclear Test Ban Treaty (CTBT). There is a site in the ‘Windless Blight’ in Antarctica near McMurdo Station that a couple of techs go dig out and maintain every year. I believe there are about 30 around the world. https://www.ctbto.org/verification-regime/monitoring-technologies-how-they-work/infrasound-monitoring/ https://www.ctbto.org/verification-regime/monitoring-technol...

rcthompson 8y ago

I wonder whether the sound wave got stronger again as it reached the opposite side of the globe from the source. Would it have made it back into the audible range? Maybe not, since I imagine that intervening mountains and such would disrupt or change the speed of the waves.

edge17 8y ago

Regarding magnitude of these types of events, NOAA does amazing work collecting data on tsunami events with impressive energy simulations. As some point I had seen several videos from the Chile event in 2010 that showed the shockwaves traveling around the earth multiple times, but I can't seem to find those videos now. Here's a link to one of the videos with an energy plot from the Chile event - https://nctr.pmel.noaa.gov/chile20100227/20100227Chile.mov https://nctr.pmel.noaa.gov/chile20100227/20100227Chile.mov And the specific Chile event page - https://nctr.pmel.noaa.gov/chile20100227/weblink.html https://nctr.pmel.noaa.gov/chile20100227/weblink.html If you browse around the site, there is a lot of information for many of the largest earthquake/tsunami events in recent times.

edge17 8y ago
And a youtube link to some more forecast models from the Pacific Tsunami Warning Center's youtube channel https://www.youtube.com/playlist?list=PLd18vQxXt2zNmVDB2NQxV-lnkL2bZtlLQ https://www.youtube.com/playlist?list=PLd18vQxXt2zNmVDB2NQxV...

brian-armstrong 8y ago

This must be the article so interesting it landed on HN Front Page Four Times :)

andyidsinga 8y ago

my ears almost hurt reading this: > The British ship Norham Castle was 40 miles from Krakatoa at the time of the explosion. The ship’s captain wrote in his log, “So violent are the explosions that the ear-drums of over half my crew have been shattered. My last thoughts are with my dear wife. I am convinced that the Day of Judgement has come.”