What if significant explosions from outer space have influenced the history of Earth without leaving visible craters? Recent research published on December 19, 2025, indicates that "touchdown airbursts" – explosions from comets or asteroids occurring above the surface – could be much more frequent and damaging than previously believed. Led by James Kennett from UC Santa Barbara, four studies featured in PLOS One and Airbursts and Cratering Impacts provide evidence from ancient locations, implying that these "invisible" occurrences have instigated climate changes, extinctions of megafauna, and even disasters affecting humans. Let us delve into this neglected hazard and understand why it requires greater scrutiny.
The Hidden Danger of Airbursts
In contrast to impacts that create craters, touchdown airbursts detonate within the atmosphere, releasing intense heat and pressure across extensive regions without leaving traditional scars. "Touchdown events can inflict severe damage due to extremely high temperatures and pressures," stated Kennett. "However, they do not necessarily result in a crater, or they may create temporary surface disturbances, but they do not produce the typical large craters associated with direct impacts." Evidence supporting this includes shocked quartz characterized by unique fractures, meltglass, minute spheres, and uncommon cosmic elements such as platinum and iridium. These indicators can be found in locations that span thousands of years, from the Younger Dryas approximately 12,800 years ago to the Tunguska event in 1908.
Younger Dryas: A Cosmic Cataclysm
The Younger Dryas was characterized by abrupt cooling, the extinction of megafauna, and shifts in human populations. Kennett’s research team discovered the earliest marine evidence in the sediments of Baffin Bay, located off the coast of Greenland at a depth of 2,000 meters, which is abundant in impact markers. "Baffin Bay holds great importance as it marks the first instance where we have identified evidence of the Younger Dryas cosmic impact event within the marine geological record," Kennett stated. "The material was ejected into the atmosphere and subsequently transported and deposited globally in a widely distributed layer. Additionally, a potential crater located at Perkins Lake in Louisiana, featuring a raised rim and impact materials that have been dated to the relevant period, adds to the intrigue. "Until now, there has been no evidence of any crater or potential crater associated with the Younger Dryas boundary (YDB) event," Kennett remarked.
Tunguska and Tall el-Hammam: Modern Echoes
The Tunguska event of 1908 devastated the forests of Siberia without leaving a crater. Kennett's examination revealed the presence of shocked quartz, meltglass spheres, and carbon – indicators of an airburst. "What is particularly intriguing about Tunguska is that it stands as the sole documented historical touchdown event," he remarked. In the Levant, at Tall el-Hammam, which was destroyed 3,600 years ago, comparable markers imply that an airburst obliterated the city.
Why This Matters Now
Airbursts are significantly more frequent and have a considerably greater destructive capacity compared to the more localized, traditional crater-forming impacts caused by asteroids," warns Kennett. "The devastation resulting from touchdown events can be far more extensive. However, they have not been thoroughly researched, making them a topic of concern for humanity. As threats from space increase, gaining insight into airbursts may enhance our defenses and provide explanations for historical disruptions.
Reference:
- A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay – PLOS One
- Destructive cosmic airbursts likely more common than previously believed – The Current, UC Santa Barbara
- Earth may have been ravaged by “invisible” explosions from space – ScienceDaily
- Evidence of a 12,800-year-old Shallow Airburst Depression in Louisiana with Large Deposits of Shocked Quartz and Melted Materials – scienceOPEN