NASA Tests Earthquake-Seeking Balloons as Way to Study Venus
2021-06-28
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1U.S. space agency researchers successfully used balloons to detect earthquakes in the California desert.
2The experiment tested whether similar balloons could be sent to Venus to study that planet's seismic activity.
3NASA recently announced plans to launch two future missions to Venus.
4The NASA scientists got the chance to carry out the test in July 2019, when a series of powerful earthquakes struck the area around Ridgecrest, California.
5The main earthquake took place on July 4 and had a magnitude of 6.4, the United States Geological Survey reported in May.
6Several other large quakes hit the area within days and more than 10,000 aftershocks were reported over the next six weeks.
7The experiment involved four large sun-powered balloons designed to fly at altitudes of 18 to 24 kilometers.
8The team attached instruments to the balloons that measure changes in air pressure.
9The equipment is used to detect sound waves that rise up from beneath the surface during earthquakes and aftershocks.
10The researchers say that by studying seismic wave activity of a rocky planet, like Earth, they can learn more about how that planet developed and about its current state.
11Venus is also a rocky planet.
12It is our closest neighbor in the solar system and the second closest planet to the sun.
13It is similar in structure to Earth, but a little smaller.
14But unlike Earth, Venus has an extremely hot surface temperature and a very dense atmosphere.
15Such conditions make it difficult for spacecraft to survive in Venus' atmosphere or on its surface.
16Scientists have long thought about the possibility of studying seismic activity on Venus.
17They want to learn more about how the planet developed such extreme conditions.
18The researchers, from NASA's Jet Propulsion Laboratory (JPL), think they can send balloons like the ones tested in California on a mission to Venus.
19The experiment -- which also involved scientists from the California Institute of Technology (Caltech) --was recently described in a study in Geophysical Research Letters.
20Scientists from JPL and Caltech have been developing their balloon-based method since 2016.
21But the heavy earthquake activity in the California desert in July 2019 gave them a good chance to test their equipment in the field.
22Seismic energy from earthquakes is transmitted into the atmosphere and produces sound waves.
23These waves are detected by ground-based seismic stations.
24But the JPL team reported it was able to detect, for the first time, earthquake related seismic activity from its balloons.
25One of the balloons detected seismic sound waves seconds after a 4.2 magnitude aftershock was confirmed by ground-based detection stations.
26At the time, the balloon was about 4.8 kilometers above the Earth.
27The researchers hope the balloons will permit new studies of seismic activity on Venus to provide information about the planet's interior.
28For example, they say this method could help them learn why the surface of Venus stays hot enough to melt lead.
29It may also lead to discoveries of liquid, such as water or oil, on the planet.
30Jennifer M. Jackson is a professor of mineral physics at Caltech's Seismological Laboratory who helped lead the research.
31She said in a statement that much of our understanding about Earth's interior comes from the study of seismic activity happening deep inside the planet.
32The method could also be possible with Venus.
33"Observations of seismic activity...would strengthen our understanding of rocky planets.
34But Venus' extreme environment requires us to investigate novel detection techniques."
35The researchers say they plan to continue flying balloons over seismically active areas to improve their ability to identify seismic events over wide areas from the air.
36They also plan to add more instruments and fly more balloons at the same time.
37This could permit them to identify where earthquakes happen without the need for confirmation from ground stations.
38I'm Bryan Lynn.
1U.S. space agency researchers successfully used balloons to detect earthquakes in the California desert. 2The experiment tested whether similar balloons could be sent to Venus to study that planet's seismic activity. NASA recently announced plans to launch two future missions to Venus. 3The NASA scientists got the chance to carry out the test in July 2019, when a series of powerful earthquakes struck the area around Ridgecrest, California. The main earthquake took place on July 4 and had a magnitude of 6.4, the United States Geological Survey reported in May. Several other large quakes hit the area within days and more than 10,000 aftershocks were reported over the next six weeks. 4The experiment involved four large sun-powered balloons designed to fly at altitudes of 18 to 24 kilometers. The team attached instruments to the balloons that measure changes in air pressure. The equipment is used to detect sound waves that rise up from beneath the surface during earthquakes and aftershocks. 5The researchers say that by studying seismic wave activity of a rocky planet, like Earth, they can learn more about how that planet developed and about its current state. 6Venus is also a rocky planet. It is our closest neighbor in the solar system and the second closest planet to the sun. It is similar in structure to Earth, but a little smaller. But unlike Earth, Venus has an extremely hot surface temperature and a very dense atmosphere. Such conditions make it difficult for spacecraft to survive in Venus' atmosphere or on its surface. 7Scientists have long thought about the possibility of studying seismic activity on Venus. They want to learn more about how the planet developed such extreme conditions. 8The researchers, from NASA's Jet Propulsion Laboratory (JPL), think they can send balloons like the ones tested in California on a mission to Venus. The experiment -- which also involved scientists from the California Institute of Technology (Caltech) --was recently described in a study in Geophysical Research Letters. 9Scientists from JPL and Caltech have been developing their balloon-based method since 2016. But the heavy earthquake activity in the California desert in July 2019 gave them a good chance to test their equipment in the field. 10Seismic energy from earthquakes is transmitted into the atmosphere and produces sound waves. These waves are detected by ground-based seismic stations. But the JPL team reported it was able to detect, for the first time, earthquake related seismic activity from its balloons. 11One of the balloons detected seismic sound waves seconds after a 4.2 magnitude aftershock was confirmed by ground-based detection stations. At the time, the balloon was about 4.8 kilometers above the Earth. 12The researchers hope the balloons will permit new studies of seismic activity on Venus to provide information about the planet's interior. For example, they say this method could help them learn why the surface of Venus stays hot enough to melt lead. It may also lead to discoveries of liquid, such as water or oil, on the planet. 13Jennifer M. Jackson is a professor of mineral physics at Caltech's Seismological Laboratory who helped lead the research. She said in a statement that much of our understanding about Earth's interior comes from the study of seismic activity happening deep inside the planet. The method could also be possible with Venus. 14"Observations of seismic activity...would strengthen our understanding of rocky planets. But Venus' extreme environment requires us to investigate novel detection techniques." 15The researchers say they plan to continue flying balloons over seismically active areas to improve their ability to identify seismic events over wide areas from the air. They also plan to add more instruments and fly more balloons at the same time. This could permit them to identify where earthquakes happen without the need for confirmation from ground stations. 16I'm Bryan Lynn. 17Bryan Lynn wrote this story for VOA Learning English, based on reports from NASA, Geophysical Research Letters and the U.S. Geological Survey. Mario Ritter, Jr was the editor. 18We want to hear from you. Write to us in the Comments section, and visit our Facebook page. 19_________________________________________________ 20Words in This Story 21detect - v. to discover or notice something 22seismic - adj. relating to or caused by an earthquake 23mission - n. a flight by an aircraft or spacecraft to perform a specific task 24transmit - v. to send out signals 25interior - n. the inside part of something 26novel - adj. new or different from anything else 27technique - n. a particular or special way of doing something