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Seismology is about waves. The epicenter of an earthquake is like a stone falling into a well. The agitation goes out across the Earth’s crust. This movement becomes a change in the pressure of the air above the ground. This creates infrasound waves (because long and slow sound waves are so low that humans cannot hear them) they pass through the atmosphere directly through the epicenter (epicentral waves) and travel over the earth over seismic waves (surface waves).
On Earth, a network of terrestrial seismology stations uses sensors to detect these waves and identify the epicenter and force of earthquakes. New research has shown how a sensor-equipped balloon can do the same thing from the air. Only epicentral barometers carried by the balloon or ground-based infrasound waves can provide some insight into the location and strength of the earthquake. One that captures both can tell what the crust of a planet looks like. That could be useful for expanding the surface of a planet we can’t really see.
(Seismological data also apply to us can see. Marsquake readings at InSight lander have been invaluable over the years Mapping the crust of Mars.)
To prove that it was possible to study Venus ’seismology from the air, the team organized a flight campaign in Oklahoma — earthquakes often occur, probably due to fracking — to see if they could hear the infrasound of Earth’s roar from above the atmosphere. . But when the Ridgecrest earthquakes occurred near JPL’s Los Angeles base in 2019, causing thousands of small aftershocks, program director James Cutts, research technologist Siddharth Krishnamoorthy and others in the group sensed the opportunity. “This had to be done quickly, more and more late, weaker and fewer replicas,” says Krishnamoorthy.
The problem: they didn’t have a balloon yet. Over the course of 16 days, four fought to build an ultralight “heliotropes, ”Simple balloons with a diameter of about 20 meters and a height of 12 meters, made using plastic sheeting and tape. The heliotropes — called Tortoise, Hare, Hare 2, and CrazyCat — rose into the stratosphere as the sun warmed the inside of the “envelope” inside the charcoal-covered plastic balloon. They floated freely in the wind, each with a bundle of barometric sensors hanging from a lower rope, listening to the faint sounds of an accident.
On July 22, 2019, the earth shook with this accident. Passing under the balloons, they caused the turbulence of surface infrasound waves to travel upwards of 4.8 kilometers and hit the Tortoise barometer, recording it as a small change in pressure. Because these changes were so small, Krishnamoorthy data had to be analyzed in order to be seen after the flight. But there they were: the small profiles of the waves coinciding with the earthquake readings of the four seismometric stations on Earth near the balloons. They matched the computer models of infrasound propagation after the replica. The turtle heard the earthquake.
But can a balloon pick up seismic infrasound as it floats in the atmosphere Venus? There, the balloon would be much much taller – about 50 miles. 5. At that height, the acid clouds of Venus it can weaken sound waves, somewhat more difficult to detect. (What is Venus like? Here’s what Bach might look like On Earth, on Titan, on Venus, and on Mars, due to different factors to mitigate sound waves.)
However, other factors would work in favor of the ball. Although Venusian winds blow continuously at more than 200 miles per hour, a balloon of stable height should be relatively “calm” in the wind. (Imagine the peace of mind of being in a balloon that travels at the same speed as the wind). Byrne writes that because Venus’s atmosphere is very thick, Byrne wrote that the surface of Venus is more efficiently 60 times more efficient than Earth, which means that earthquake energy will be much more easily transmitted to Venus’ atmosphere, the first place to float a seismometer. becoming.
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