Earth’s atmosphere vibrates with explosions almost daily

A new study published in the ScienceOpen journal Airbursts and Cratering Impacts has revealed new insights into the potentially devastating effects of cosmic airbursts.
These explosive events, caused by space rocks or comet fragments crashing into Earth’s atmosphere, occur more frequently than large asteroid impacts but have been poorly understood until now.
Led by UC Santa Barbara emeritus earth scientist James Kennett, researchers have developed detailed models of “touchdown” airbursts – explosions that occur close enough to Earth’s surface to cause significant damage.
These events, happening on timescales of years to centuries, are more common than previously thought and potentially more dangerous than large crater-forming impacts.
The team focused on modeling low-altitude airbursts, occurring 700 meters or less above Earth’s surface.

They simulated various scenarios involving asteroids and comets of different sizes, comparing their results with real-world data from historical events like the Tunguska (1908) and Chelyabinsk (2013) airbursts in Russia, as well as the 1945 Trinity nuclear test in New Mexico.
Using advanced hydrocode computer models, the researchers were able to predict the effects of these airbursts, including changes in pressure, temperature, shockwave speed, and material failure.
Their simulations showed how such events could produce meltglass, microspherules, and shock metamorphism in quartz – telltale signs of extreme heat and pressure.
Kennett emphasised that these airbursts can cause significant damage without leaving distinct craters, making them harder to identify in the geological record. The study’s findings could help scientists better understand and interpret evidence of past cosmic impacts at various sites worldwide.
In a related paper, the team applied their model to the archaeological site of Tall el-Hammam near the Dead Sea. Their analysis supports the hypothesis that an airburst was responsible for the city’s destruction during the Middle Bronze Age, potentially linking it to the biblical story of Sodom and Gomorrah.
This research not only advances our understanding of cosmic threats but also provides valuable tools for identifying and studying past impact events.