Close encounters #3: Asteroiden scheren langs de aarde

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Eight bright fireballs reported over U.S. in March as spring fireball season returns

Eight bright fireballs were reported over the U.S. between March 3 and 24, 2026, drawing renewed attention to a seasonal increase in fireball activity often seen around the March equinox. NASA has long said sporadic fireball rates can rise by about 10% to 30% during this period, a pattern recognized for more than four decades, even though its cause remains unresolved.

At least eight bright fireballs were reported over the U.S. from March 3 to 24, 2026, drawing renewed discussion over why so many have been seen this month. The increase is consistent with a seasonal rise in fireball activity often observed around the March equinox.

The increase is associated with the weeks around the March equinox, when the Sun crosses the celestial equator and the Northern Hemisphere spring begins. NASA has long noted that bright sporadic fireballs tend to become more common during this period.

According to NASA, the rate of sporadic fireballs can increase by about 10% to 30% during this period. What makes the pattern notable is that no single explanation for it has been confirmed.

Researchers have recognized the pattern for decades, but no single explanation has been confirmed.

One proposed explanation involves the geometry of Earth’s motion through space and the direction from which meteoroids encounter the atmosphere. In simple terms, some researchers have suggested that seasonal viewing geometry may favor faster, more direct encounters with particles large enough to produce bright fireballs.

Another possibility is that Earth passes through a somewhat denser region of meteoroidal debris during this part of its orbit, increasing the likelihood of bright entries.

Another theory involves velocity and size. Meteoroids enter Earth’s atmosphere at speeds starting near 11 km/s (6.8 miles/s), and brighter fireballs are generally produced by larger objects and higher-energy entries, which generate stronger compression heating and more intense ablation in the upper atmosphere.

Some of the increase may also reflect observational bias, including more people outdoors in spring and a larger number of cameras capturing events. However, the pattern has been recognized for decades, suggesting that viewing conditions alone do not fully explain it.

While these ideas offer partial explanations, none have been confirmed, and the cause of the spring fireball surge remains unresolved