Pre-Impact Detections

As surveys scan the sky, with the main goal of discovering objects large enough to cause damage at Earth’s surface, they will occasionally detect much smaller objects on a collision course with Earth. Those objects are generally just a few meters in size, while impacts by larger objects are much less frequent and happen over very long timescales on average. The table below provides information about objects that have been detected in space by telescopes prior to entering Earth’s atmosphere and subsequently designated by the Minor Planet Center.

The impact time and geographic coordinates correspond to when the object reached the listed altitude above Earth’s surface. This altitude may correspond to where the object disrupted, or to a location on Earth’s surface if the object reached the surface primarily intact.

We reference to relevant journal publications when available. Otherwise, impact parameters from the US government fireball report are listed if available. In cases with no publication and no fireball report, the parameters are computed using the trajectory available on the small body database, assuming a reference altitude of 50 km, and listed as “JPL Solution”.

When size estimates are not available, they are computed as a range using the absolute magnitude and limiting albedos of 0.25 and 0.05.