In this 1-minute video, EarthSky’s Will Triggs tells you about the human-made meteor shower that could be on its way to Earth.

• In 2022, the DART spacecraft struck a small asteroid as part of a test to see if deflecting asteroids is a possibility for planetary defense.
• The impact blasted rocks and dust from the asteroid’s surface.
• Now, it seems, this asteroid debris might strike us. But don’t worry. It’ll burn up in Earth’s atmosphere, creating a meteor shower.

Human-made meteor shower from DART impact

Astronomers talked for years about possible methods of planetary defense: ways to deflect an asteroid on a collision course with Earth. Then, in 2022, they tried it. NASA’s DART spacecraft was made to plow into a distant asteroid moon, a tiny body called Dimorphos, successfully nudging it slightly from its path. The test blasted more than 2 million pounds (or nearly 1 million kilograms) of asteroidal rock and dust into space. And now, a new study says this debris – kicked up from asteroid Dimorphos in the name of planetary defense – might enter the realm of space where Earth orbits, causing a meteor shower in our skies. It’ll be the 1st-ever human-made meteor shower. The rocks and dust could hit Mars in as soon as 7 years from now … and strike Earth’s atmosphere within 10 years. There’s no danger. But it could be something to see.

In fact, the paper said:

Larger particles exhibit a marginally greater likelihood of reaching Mars, while smaller particles favor delivery to Earth-moon, although this effect is insignificant.

DART stands for Double-Asteroid Redirection Test.

Striking Mars and Earth

The largest of the debris would only be about the size of a softball. Earth’s thick atmosphere will disintegrate any meteors from this shower, but Mars’ thinner atmosphere might mean some large pieces could make it through.

Co-author Josep M. Trigo-Rodríguez from the Spanish Institute of Space Sciences (CSIC/IEEC) said:

We were amazed to discover that it is possible for some centimeter-sized [less than 1/2 inch-sized] particles to reach the Earth-moon system and produce a new meteor shower.

The study has been accepted for publication in The Planetary Science Journal, and a preprint dated September 2, 2024, is available on arXiv.

Fallout from the DART impact

While the DART mission was successful in its attempt to shift an asteroid off-course, follow-up studies continue. ESA is launching a mission named Hera to continue observations of Dimorphos and its larger parent asteroid Didymos. ESA said:

ESA’s Hera spacecraft will be launched this October to reach Dimorphos and perform a close-up ‘crash scene investigation’, gathering data on the asteroid’s mass, structure and make-up to turn this kinetic impact method of planetary defense into a well understood and repeatable technique.

A co-author of the new study and ESA Hera mission scientist Michael Kueppers said:

The DART impact offers a rare opportunity to investigate the delivery of ejecta to other celestial bodies, thanks to the fact that we know the impact location and that this impact was observed by the Italian LICIACube deployed from DART as well as by Earth-based observers.

We simulated the ejecta to match LICIACube observations using three million particles grouped into three size populations – 10 cm (3.9 inches), 0.5 cm (0.2 inches) and 30 micrometer, or thousandths of a millimeter (1 millimeter equals 0.04 inches) – moving at speeds of 1 to 1000 m/s (2.2 to 2,237 mph) or a faster rate of up to 2 km/s (4,474 mph).

A view of DART impacting asteroid Didymos from Earth.

The first human-made meteor shower

The human-made meteor shower is not a guarantee, but it’s definitely possible. Lead author Eloy Peña-Asensio of the Department of Aerospace Science and Technology, Politecnico di Milano said:

We identified ejecta orbits compatible with the delivery of meteor-producing particles to both Mars and Earth. Our results indicate the possibility of ejecta reaching the gravitational field of Mars in 13 years for launch velocities around 450 m/s (1,000 mph), while faster ejecta launched at 770 m/s (1,722 mph) could reach its vicinity in just seven years. Particles moving above 1.5 km/s (3,355 mph) could reach the Earth-Moon system in a similar timescale.

In the coming decades, meteor observation campaigns will be crucial in determining whether fragments of Dimorphos, resulting from the DART impact, will reach our planet.

If this happens, we will witness the first human-made meteor shower.

A new May meteor shower in our skies

When the meteors hit Earth’s atmosphere, they’ll light up, and the color they emit can give clues to the composition of the rocks and dust. Kueppers said:

The exciting thing is the prospect of identifying and observing meteors linked to the DART impact, either on Earth or perhaps one day even on Mars, with their brightness and color revealing details of their makeup.

As for us Earthly observers, we should expect the meteors in the month of May a decade or so from now. And the shower could return periodically for at least 100 years. However, it will favor those in the Southern Hemisphere. Kueppers said:

Our study includes the distinct orbital characteristics that would distinguish these meteors from comparable ones. The potential meteors created by DART would be slow-moving, primarily visible from the southern hemisphere, and most likely to occur in May.

Bottom line: When the DART spacecraft hit the asteroid Dimorphos, it released a torrent of debris that should arrive at Mars and Earth, creating the first human-made meteor shower for the planets.

Source: Delivery of DART Impact Ejecta to Mars and Earth: Opportunity for Meteor Observations

Via ESA