#venusian seismology | Explore Tumblr Posts and Blogs

daniloqp · 3 years

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Scientists could one day float an aerial robot over Venus

https://theministerofcapitalism.com/blog/scientists-could-one-day-float-an-aerial-robot-over-venus/

Seismology deals with waves. The epicenter of an earthquake is like a stone falling into a pond. The perturbation tilts outward along the earth’s crust. This movement results in a change in air pressure just above the ground. This produces infrasound waves (long, slow sound waves so low that humans cannot hear them) that travel through the atmosphere both from the epicenter (epicenter waves) and above the seismic waves as they travel through the earth (surface waves).

On Earth, a network of seismological earth stations uses sensors to detect these waves and identify the epicenter and force of earthquakes. The new study shows how a balloon equipped with sensors can do the same from the air. A balloon barometer that captures only waves of ground or epicenter infrasound can give some information about the location and strength of an earthquake. One that captures both could tell what the crust of a planet is like. This could be useful within reach of the surface of a planet that we can’t really see.

(Seismological data also work for us tin I’ll see. InSight platform earthquake readings have been invaluable cartography of the Martian crust.)

To show that studying the seismology of Venus from the air was possible, the team planned a flight campaign to Oklahoma (where earthquakes are frequent, probably due to fracking), to see if they could hear the infrasound of the rumors of the Earth from very high in the atmosphere. . But when the Ridgecrest earthquake series occurred near JPL’s home base in Los Angeles in 2019, it sparked thousands of small aftershocks, senior program manager James Cutts, research technologist Siddharth Krishnamoorthy and other members of the team felt a chance. “This had to be done quickly, because the later it happened, the weaker and fewer the aftershocks were,” Krishnamoorthy says.

Problem: They didn’t have balloons yet. Over the course of a frantic 16 days, they fought to build four ultralights. “heliotropes“Simple balloons about 20 feet in diameter and 12 feet high, made of sheets of plastic and duct tape. Heliotropes, called Tortoise, Hare, Hare 2, and CrazyCat, rose into the stratosphere as the sun warmed. the air inside their charcoal-covered plastic balloon “envelopes.” They floated freely in the breeze, each with a bundle of barometric sensors hanging from a ligature underneath, listening to the very faint sounds of a replica.

On July 22, 2019, the ground shook with that aftershock. Passing under the balloons, it produced surface infrasound wave disturbances that traveled 4.8 kilometers upward and hit the Tortoise barometer, registering as a series of small pressure changes. These changes were so small that it took Krishnamoorthy months to analyze the data after the flight to see them. But there they were: small wave profiles that match perfectly the earthquake readings of four Earth seismometer stations in the area near the balloons. They also matched computer models of infrasound propagation from the replica. The turtle had felt the earthquake.

But a balloon could pick up seismic infrasound as it floated in the atmosphere Venus? There, the balloon would fly much, much higher, about 50 kilometers instead of 5. At this altitude, the acid clouds of Venus it can attenuate infrasound waves, making them a little harder to detect. (What does Venus sound like? This is what Bach might look like on Earth, Titan, Venus and Mars, due to different sound wave attenuation factors.)

However, other factors would work in favor of the balloon. Although Venusian winds blow constantly at more than 200 miles per hour, a balloon at a stable altitude should remain relatively “calm” as it breezes along. (Imagine the calm of being in a hot air balloon, traveling at the same speed as the wind.) Because of Venus ‘super-thick atmosphere, writes Byrne, Venus’ surface is coupled to this atmosphere about 60 times. times more efficiently than Earth is what means that the energy of an earthquake will be transmitted much more easily to the atmosphere of Venus, making it an ideal place for the floating of a seismometer.

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