Skip to main content

Astronomers model an asteroid striking Earth using asteroid Apophis

An international team of space researchers recently came together to test what might happen if Earth were threatened by a large asteroid strike. Results from the planetary defense exercise, which happened last year, have just recently been published and show the steps that would need to be taken if a planet-killing asteroid was headed for us.

To simulate the threat, the participants considered asteroid Apophis. This real 1,100-foot-long asteroid will come close to Earth in 2029 and 2068, but won’t actually strike the planet. But for the sake of the exercise, the participants worked out what could have happened if it had threatened Earth on its most recent close approach between December 2020 and March 2021.

Clockwise from top left are three of the observatories that participated in a 2021 planetary defense exercise: NASA’s Goldstone planetary radar, the Mount Lemmon telescope of the Catalina Sky Survey, and NASA’s NEOWISE mission. At bottom left is an illustration of the path of Apophis’ close approach in 2029.
Clockwise from top left are three of the observatories that participated in a 2021 planetary defense exercise: NASA’s Goldstone planetary radar, the Mount Lemmon telescope of the Catalina Sky Survey, and NASA’s NEOWISE mission. At bottom left is an illustration of the path of Apophis’ close approach in 2029. NASA/JPL-Caltech/University of Arizona

“This real-world scientific input stress-tested the entire planetary defense response chain, from initial detection to orbit determination to measuring the asteroid’s physical characteristics and even determining if, and where, it might hit Earth,” said Vishnu Reddy, associate professor at the University of Arizona’s Lunar and Planetary Laboratory in Tucson, in a statement.

Recommended Videos

The asteroid was tracked using NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission, which gathered information on its size and shape. This is important to estimate how much damage would be done by an impact and was used in simulations of possible impact locations on Earth. The idea is that this data could be sent to disaster agencies to help their efforts in the case of a real incoming asteroid.

Please enable Javascript to view this content

“Seeing the planetary defense community come together during the latest close approach of Apophis was impressive,” said Michael Kelley, a program scientist with PDCO, within NASA’s Planetary Science Division. “Even during a pandemic, when many of the exercise participants were forced to work remotely, we were able to detect, track, and learn more about a potential hazard with great efficiency. The exercise was a resounding success.”

The findings are published in The Planetary Science Journal.

Georgina Torbet
Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…
NASA has collected a whopping 121 grams of sample from asteroid Bennu
A view of eight sample trays containing the final material from asteroid Bennu. The dust and rocks were poured into the trays from the top plate of the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) head. 51.2 grams were collected from this pour, bringing the final mass of asteroid sample to 121.6 grams.

When the OSIRIS-REx dropped a capsule in the Utah desert last year, it made headlines around the globe for returning NASA's first sample of an asteroid to Earth. Scientists were eager to get their hands on the sample of asteroid Bennu to learn about the early formation of the solar system, but actually getting at the sample proved to be rather trickier than imagined.

Scientists were able to extract 70 grams of material from the sample canister relatively easily, making it by far the largest asteroid sample ever brought to Earth, but two troublesome fasteners made it difficult to extract the rest of the sample. The team knew it had plenty more sample inside, but it had to be patient as special new tools were constructed that could undo the fasteners without losing a single gram of the precious sample.

Read more
Astronomers discover a super-Earth located in the habitable zone
This illustration shows one way that planet TOI-715 b, a super-Earth in the habitable zone around its star, might appear to a nearby observer.

Astronomers have discovered a type of exoplanet called a "super-Earth" located in the habitable zone of its small star, and it's right in our cosmic backyard, just 137 light-years away. The planet, named TOI-715 b, is intriguing to astronomers who are increasingly interested in the possibility of habitable planets orbiting stars quite different from our sun.

Although it might seem to make sense to look for potentially habitable planets when looking for Earth-like planets orbiting sun-like stars, those aren't the only targets that astronomers are interested in. One issue is that most discovered exoplanets are much larger than Earth, partly because it is so hard to detect smaller planets. Another issue is that the most common star in our galaxy by far is not a yellow dwarf star like our sun, but a smaller, dimmer, redder type called a red dwarf. When researchers discover rocky planets orbiting around red dwarfs, a few of which have been identified to date, that increases the pool of potentially habitable worlds that could be out there.

Read more
NASA automated system predicts asteroid impact over Germany
This map shows the location where the small asteroid 2024 BX1 harmlessly impacted Earth’s atmosphere over Germany, about 37 miles (60 kilometers) west of Berlin, on Jan. 21. A NASA system called Scout predicted the impact time and site within 1 second and about 330 feet (100 meters).

Earth is frequently bombarded by small asteroids, which burn up harmlessly in the atmosphere. However, identifying and tracking these asteroids is an important step in protecting the Earth against the threat of larger and potentially more dangerous impacts. NASA recently predicted the impact of a small asteroid that struck Germany using its impact prediction system, Scout.

"A small asteroid about 3 feet (1 meter) in size disintegrated harmlessly over Germany on Sunday, Jan. 21, at 1:32 a.m. local time (CET)," NASA wrote in an update. "At 95 minutes before it impacted Earth’s atmosphere, NASA’s Scout impact hazard assessment system, which monitors data on potential asteroid discoveries, gave advance warning as to where and when the asteroid would impact. This is the eighth time in history that a small Earth-bound asteroid has been detected while still in space, before entering and disintegrating in our atmosphere."

Read more