Updated

Updated · Space.com · Aug 10

1972 Fireball Crossed North America in 100 Seconds as Earth-Grazer Skimmed Back Into Space

Updated

Updated · Space.com · Aug 10

1972 Fireball Crossed North America in 100 Seconds as Earth-Grazer Skimmed Back Into Space

Q: What catastrophic damage was narrowly avoided when the 45-foot Great Daylight Fireball bounced back into space instead of striking Earth?

It narrowly avoided a regional airburst or ground impact that could have caused severe local destruction—but not a civilization-ending catastrophe. The 1972 Great Daylight Fireball was estimated at roughly 10 to 45 feet across and skimmed through the atmosphere before bouncing back into space. At that size, scientists do not compare it to the dinosaur-killing Chicxulub impactor. A 45-foot rocky object striking Earth would more likely have exploded in the atmosphere or hit with energy on the scale of a powerful bomb, capable of shattering windows, producing a damaging shock wave, and potentially injuring or killing people over a limited area. The best modern comparison is the 2013 Chelyabinsk meteor over Russia, which was larger, exploded in the atmosphere, and injured more than 1,000 people, mostly from broken glass. If the 1972 object had come in on a steeper path over a populated area, it could have caused similar or somewhat smaller devastation depending on its composition, speed, and breakup behavior. So the catastrophe that was narrowly avoided was not global annihilation, but a potentially destructive impact or airburst over part of the western United States or Canada, with serious local damage and casualties if it had reached lower altitudes or the ground.

3 articles · Updated · Space.com · Aug 10

A rare daytime fireball entered Earth's atmosphere over Utah on Aug. 10, 1972, streaked north across North America and exited over Alberta about 100 seconds later without hitting the ground.
Trajectory analysis put the object at roughly 10 to 45 feet wide, with the size range depending on whether it was an icy comet fragment or a denser rocky asteroid.
Its brightness set it apart from ordinary meteors: the object was large and fast enough to remain visible in broad daylight, unlike typical night-sky streaks made by much smaller dust or rock particles.
An event like that today would likely be captured by millions across the United States and Canada, highlighting how unusual the 1972 'Great Daylight Fireball' was in the pre-social-media era.