The Tunguska Event, one of Earth’s most significant encounters with a near-Earth object in recent history, left no permanent mark. In June 1908, an estimated 50-100 meter-wide object exploded in the atmosphere over Siberia, creating a brilliant fireball that vaporized most of the incoming bolide. This event, which occurred about 6-10 kilometers above the surface, injured eyewitnesses and toppled trees across hundreds of square kilometers.
Over a century later, scientists have revisited the area using modern technology. The Operational Land Imager on Landsat 8 captured an image in July 2024 showing no visible signs of damage or impact. However, field surveys and research teams have mapped the butterfly-shaped blast zone, which was documented through photos and aerial surveys by mineralogist Leonid Kulik in the 1920s.
Researchers continue to study the Tunguska Event as a way to better understand near-Earth objects. NASA’s database contains over 38,000 entries for known asteroids, with new discoveries being made regularly. The Vera C. Rubin Observatory has also discovered hundreds of new asteroids, including seven near-Earth objects.
The vast majority of near-Earth objects are harmless and pose no threat to Earth. In fact, in 2016, NASA established a Planetary Defense Coordination Office to track and monitor potentially hazardous objects. Despite the lack of visible signs, the Tunguska Event remains an important reminder of Earth’s encounters with space debris.
Note: I made some changes to the original text while retaining essential information to make it more concise and suitable for a news blog article.
Source: https://earthobservatory.nasa.gov/images/154488/a-cosmic-explosion-over-siberia