Solarseven/Getty Images
Asteroid impacts are a stark reminder of Earth’s vulnerability to cosmic events. While most impacts are harmless, history records several that have reshaped the planet’s environment and life. NASA’s Near‑Earth Object Studies Center monitors potential threats, and the latest data confirm that no large‑scale impact is expected in the next century. Nevertheless, recent close approaches—such as the 2022 city‑destroying asteroid that narrowly missed Earth—highlight the persistent risk. Below is a detailed look at the 13 largest known asteroid impacts, their scale, and their lasting effects.
BEST‑BACKGROUNDS/Shutterstock
The Siljan Ring, a nearly perfect circular basin in Sweden’s Dalarna region, marks Europe’s most massive known asteroid strike. Scientists estimate the crater’s diameter at 37 mi (60 km) and the impactor at 3.1 mi (5 km). Occurring ~380 million years ago, the event would have unleashed global shock waves and widespread ecological upheaval. Drilling projects have recovered fossilized fungi, indicating that ancient ecosystems survived the blast.
Mikael Damkier/Shutterstock
Perhaps the most famous terrestrial impact, Chicxulub’s 110‑mi (177 km) crater lies beneath Mexico’s Yucatán Peninsula. The 66‑million‑year‑old asteroid, 6–9 mi (10–15 km) across, triggered the Cretaceous‑Paleogene extinction that eliminated ~75% of Earth’s species, including dinosaurs. The impact injected dust and aerosols into the atmosphere, causing a 15‑year “impact winter” and dramatic climate shifts.
Marieke Peche/Shutterstock
The 3.26‑billion‑year‑old S2 event, recorded in South Africa’s Barberton Greenstone Belt, involved an object roughly 37 mi (60 km) wide—comparable to the Siljan Ring. The collision vaporized oceans, heated the atmosphere, and potentially created a post‑impact environment conducive to early microbial life, suggesting a paradoxical benefit from a catastrophic event.
Phittavas/Getty Images
Australasian Strewnfield tektites, dispersed over 10% of Earth’s surface, hint at a large impact ~11 million years ago. The resulting crater, estimated at 16 mi (26 km) across, would have covered the region now known as Laos. Though the precise impactor size remains uncertain, the strewnfield’s extent suggests a monumental event that may surpass the size of other known craters.
BEST‑BACKGROUNDS/Shutterstock
South Africa’s Vredefort Crater, the largest confirmed impact structure, dates to ~2 billion years ago. Early estimates placed the impactor at 9.3 mi (15 km); recent studies suggest up to 15.5 mi (25 km). The crater’s original diameter may have reached 186 mi (300 km), dwarfing Chicxulub and illustrating the magnitude of the event’s energy release.
Rhj/Getty Images
On the Taymyr Peninsula, a 5‑mi (8 km) asteroid struck ~36 million years ago, forming a 60‑mi (96 km) crater. The impact melted ~420 cubic mi (1.7 billion km³) of rock, producing microscopic diamonds in the surrounding sediment—a unique geological footnote in Earth’s history.
April.zee/Shutterstock
The 25‑mi (40 km) Chesapeake Bay crater, buried beneath the eponymous waterway, was formed by a 3‑mi (5 km) bolide 35 million years ago. The event reshaped regional topography and altered river courses, underscoring the power of even mid‑sized impacts.
Tommy Lee Walker/Shutterstock
Located in Scotland’s sandstone strata, the Stac Fada event, ~990 million years old, involved a 1.2‑mi (2 km) impactor. Its timing coincides with the emergence of freshwater eukaryotes, suggesting that such strikes may catalyze evolutionary breakthroughs.
Elen11/Getty Images
In Quebec, the 43.5‑mi (70 km) Manicouagan crater was created by a 3.1‑mi (5 km) asteroid ~214 million years ago. The ring is visible from orbit and was repurposed in the 1960s to form the Daniel‑Johnson Dam, turning the impact structure into a hydro‑electric reservoir and recreational fishing site.
Ian Peter Morton/Shutterstock
Australian researchers have identified a potential 323‑mi (520 km) crater near Deniliquin. If confirmed, it would be the largest known impact structure, surpassing Vredefort. Current evidence comes from magnetic anomalies; definitive proof requires drilling.
buradaki/Shutterstock
In the Kalahari Desert, the Morokweng crater, 145 million years old, was produced by a 3–6‑mi (5–10 km) asteroid. Although surface remnants are eroded, deep core samples have recovered 9.8‑inch (25 cm) meteorite fragments, attesting to the impact’s global significance.
BEST‑BACKGROUNDS/Shutterstock
Acraman’s inner ring, 55 mi (88 km) wide, points to an asteroid of considerable size that struck ~600 million years ago. The event likely contributed to the global cooling that defined the late Neoproterozoic, yet resilient life eventually recovered and diversified.
Buradaki/Getty Images
Buried 3,000 ft deep in Queensland’s Eromanga Basin, Tookoonooka (41 mi / 66 km) may be part of a pair of impacts, the other being Talundilly (52 mi / 84 km). These events, dated between 128–360 million years ago, could have played a role in the late Devonian extinction. Australia’s ancient crust preserves over 170 impact sites, making it a prime area for studying Earth’s bombardment history.
