The Chelyabinsk, Russia meteor emitted infrasound heard only by some animals, but heard and measured around the world from Antarctica to Greenland. What's the sound a meteor makes if in space no one can hear it --until it explodes in Earth's atmosphere or rains down on the ground?
The meteor explosion over Chelyabinsk, Russia, near the border of Kazakhstan on February 15, 2013 also produced a wave of sound too low to be heard by the human ear. But some animals may have sensed it, according to the international agency that watches for nuclear bomb tests. Maybe the wolves and dogs heard it coming or felt it approach using their ability to sense and hear infrasound, below what humans could detect with the ear.
Infrasound can be heard by elephants and a few other animals, perhaps dogs or cats, but not by the human ear. Animals may have been able to hear the meteor coming, but the sound was too low-pitched to be heard by humans. Perhaps people should watch their pet's reactions to warn them of an oncoming meteor.
Check out the video, "NASA Reveals Details of Russian Meteor Explosion [Video]." New data from the Comprehensive Test Ban Treaty Organization was gathered using infrasound sensors that normally monitor nuclear explosions.
The Comprehensive Test Ban Treaty Organization said that sound wave showed up on sensors from Greenland to Antarctica, making it the largest ever detected by its network, according to the February 28, 2013 CNN news article by Matt Smith, "Planet of sound: Meteor blast resonated around Earth." It's raining stones and drones whose sound can be measured through telephones. Check out the Time magazine article, "Russian Meteor Blast 'Heard' from Antarctica to Greenland."
The sound wave was put to good use as researchers used the giant low-pitched sound wave to calculate the size of the small asteroid that plunged to Earth, Margaret Campbell-Brown, an astronomer at Canada's University of Western Ontario, explained to CNN. The 32 seconds duration of the noise not heard around the world allowed scientists estimate the energy of the blast at between 450 and 500 kilotons, the size of about 30 early nuclear bombs.
From there, Brown told CNN, scientists could calculate the size of the fireball; and using an estimate of the meteor's speed from the numerous dashboard and mobile-phone cameras that captured the scene, it was "first-year physics" to figure out the approximate size and weight. The latest estimate is that the Chelyabinsk meteor was about 56 feet (17 meters) across, weighed more than 7,000 tons and was moving about 18 kilometers per second (40,000 mph) when it blew apart, according to the CNN article.
The meteor explosion on February 15, 2013 had been the largest since the 1908 Tunguska meteor explosion event that flattened a Siberian forest in the same nation. Check out the site, "Opinion: A meteor and asteroid: 1 in 100 million odds."
Infrasound is low frequency noise from meteors
Scientists can pick up the sound of a tiny meteor smaller than a marble. About 20 meteors each year are measured by their sound waves. Astrophysicists from NASA's Meteoroid Environment Office think that the rock originated in the asteroid belt between Mars and Jupiter. The precise location may have been the Apollo group of asteroids, which circle the sun in oblong orbits, that occasionally cross Earth's. See, "Planetary Meteor Defense Shield Proposed."
The February 15, 2013 meteor that fell over Russia was made out of stony with bits of nickel and iron, which is what most meteors are made of. If a small meteor can make such a big noise, imagine what a bigger rock can do. Now people wonder what health effects may be attributed to such a low-pitch wave below what the human ear can pick up? For further information also see the articles, "What does a meteor sound like?" and the BBC news article, "Russia meteor's origin tracked down."
A Russian official is proposing a unified international monitoring system to prevent Earth from being struck with a catastrophic blast from space
Following the destructive meteor breakup over southern Russia on February 15, Prime Minister Dmitry Medvedev assigned a deputy, Dmitry Rogozin, to find ways to prevent far worse disasters. Rogozin had proposed in 2011 an “international initiative” to prevent such threats by harnessing the “intellectual and technological efforts of industrial nations.”
If aerospace defense can detect incoming objects launched from the ground, why can't technology be built to warn people about objects coming in from space? Scientists propose a network structured under the umbrella of the United Nations to detect and deflect meteors or asteroids long before they reach the planet.
Can radio astronomy solve the problem of needed meteor defense?
Meteor defense is what the planet needs just as much as it needs aerospace defense against missiles launched from the ground or underground. But will it also detect UFOs? For further information, check out the article, ""Planetary Meteor Defense Shield Proposed."
It's one good use of radio astronomy since the famous telescope run by Manchester University in England is under threat of closure after the Science and Technology Facilities Council is struggling to finance it. The landmark is part of the eMerlin radio telescope project. Can radio astronomy be re-engineered to detect incoming space rocks? And can science find a way to send them on their way?