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02.05.2025 10:45

Space junk falling to Earth needs to be tracked. Meteoroid sounds can help.

Dr. Asmae Ourkiya EGU Executive Office
European Geosciences Union

Space junk and meteoroids are falling to Earth every year, posing a growing risk as they re-enter the atmosphere at high speeds. Researchers are using infrasound sensors to track these objects, including bolides, which are meteoroids breaking apart in the sky. New research presented at the EGU General Assembly 2025 shows that infrasound signals can help track these objects, but the trajectory needs to be considered, especially for objects entering at shallow angles. This study highlights the importance of improving monitoring techniques for planetary defense and space junk management.

Every year, Earth gets a bit bigger. Thousands of metric tons of space dust fall from the sky, while about 50 tons per year of meteorites crash land somewhere on the surface. Since the 1960s, space junk has also occasionally returned to Earth, falling from a hazy sphere of trash encircling the planet. Remnants of rockets, tools lost by space-walking astronauts, defunct satellites, and more fly through lower Earth orbit, reaching speeds of 18,000 miles per hour.

When any item—whether space rock or space junk—enters the atmosphere, scientists try to track its path to estimate where it will land. Will the item in question plunk straight down, or will it fly along at an angle before skittering to a halt? In a new study to be presented at the General Assembly of the European Geosciences Union next week, Elizabeth Silber, a scientist at Sandia National Laboratories, will consider how infrasound sensors—instruments that detect sounds at lower frequencies than humans can hear—listen for bolides. Bolides are the bright flashes and booms from large meteoroids breaking apart high in the sky. These events release huge amounts of energy, creating shock waves that travel as infrasound signals across thousands of kilometers.

But here’s the challenge: bolides aren’t like explosions that happen in one place. They are moving, generating sound along their path as they travel through the sky. This movement matters, especially for meteoroids and space debris that enter shallow angles. In those cases, different infrasound stations might pick up signals coming from different directions, making it harder to pinpoint the source. Motivated by this problem, Silber used a network of infrasound sensors around the world maintained by the Comprehensive Test Ban Treaty Organization (CTBTO), an organization tasked with listening for illicit explosions. These instruments also record anything else that claps or booms, from thunder to supersonic aircraft. Using signals specifically from bolides, Silber isolated the purely geometric component for her analysis. She found that if a bolide enters Earth’s atmosphere at a relatively steep angle— greater than 60°—analysis of the infrasound signal gets the trajectory right. But when it comes more horizontally, the uncertainty increases.

“Infrasound from a bolide is more like a sonic boom stretched across the sky than a single bang,” Silber says. "You must account for the fact that the sound is being generated along the flight path.”

And so, this study highlights a critical need: to consider the trajectory of an object when interpreting infrasound data. Infrasound instruments are indispensable for planetary defense, according to Silber, and the findings are relevant to Earth-bound space junk. If you don’t know where something is going, then you have a hard time preparing for it. If you’d like to learn more, don’t miss the full PICO presentation on Friday, 02 May at 11:28-11:30 CEST at PICO spot 5.

If you’re interested in scientific applications of data collected by the International Monitoring System managed by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), check out the full SM8.5 PICO session on Friday, 02 May, starting at 10:45 CEST. PICO sessions are given in hybrid format supported by a zoom meeting.

Dr. Silber will be attending virtually, and would be happy to answer questions via email Caption: This photograph taken by an International Space Station astronaut shows a bright meteor from the Perseid meteor shower in Earth’s atmosphere. The brightest meteors are known as fireballs, or bolides. Credit: NASA Note to the media When reporting on this story, please mention the EGU General Assembly 2025, which is taking place from 27 April– 02 May 2025. This paper will be presented in full [Session SSP1.2] at EGU25 on Fri, 02 May, 10:45–12:30 (CEST) PICO spot 5. If reporting online, please include a link to the session: https://meetingorganizer.copernicus.org/EGU25/session/53597 While media briefings and sessions are hosted by the EGU, research presented at the General Assembly is the responsibility of each presenter and does not necessarily reflect the views of the EGU.

Press contact

Asmae Ourkiya
Media and Communication Officer
media@egu.eu

More information

The European Geosciences Union (EGU) is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary, and space sciences for the benefit of humanity, worldwide. It is a non-profit interdisciplinary learned association of scientists founded in 2002 with headquarters in Munich, Germany. The EGU publishes a number of diverse scientific journals, which use an innovative open access format, and organises several topical meetings, and education and outreach activities. Its annual General Assembly is the largest and most prominent European geosciences event, attracting over 19,000 scientists from all over the world. The meeting’s sessions cover a wide range of topics, including volcanology, planetary exploration, the Earth’s internal structure and atmosphere, climate, energy, and resources.
The EGU General Assembly 2025 is taking place in Vienna, Austria and online from 27 April– 02 May 2025. For information and press registration, please click here. If you wish to receive our press releases via email, please use the Press Release Subscription Form. Subscribed journalists and other members of the media receive EGU press releases under embargo (if applicable) 24 hours in advance of public disseminate EGU25 website (https://www.egu25.eu/) has a tab titled ‘Media’ where you will find the full list of press conferences and presentations of media interest. We encourage members of the press to browse the virtual EGU25 Press Centre (https://www.egu.eu/gamedia/2025/) for our Media Tip Sheets and Media Highlights of the General Assembly 2025

About the EGU

The European Geosciences Union (EGU) is the leading organisation for Earth, planetary and space science research in Europe. With our partner organisations worldwide, we foster fundamental geoscience research, alongside applied research that addresses key societal and environmental challenges. Our vision is to realise a sustainable and just future for humanity and for the planet. The annual EGU General Assembly is the largest and most prominent European geosciences event, attracting over 19,000 scientists from all over the world. The meeting’s sessions cover a wide range of topics, including volcanology, planetary exploration, the Earth’s internal structure and atmosphere, climate, as well as energy and resources. For more information about the meeting please check media.egu.eu or follow EGU on social media.

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Originalpublikation:

https://www.egu.eu/media/filer_public/3c/84/3c845388-f6d1-4ba1-aa3e-496bfd1af87d...

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