A meteor is the streak of light created when a small piece of space debris, a meteoroid, enters Earth’s atmosphere and vaporizes high above the surface. Commonly called “shooting stars,” the ability to see them depends heavily on the surrounding brightness. The direct answer to whether one can see meteors during the day is generally no. The difficulty arises from the overwhelming brilliance of the daytime sky, which effectively hides the relatively faint light produced by a typical meteor’s atmospheric entry.
The Physics of Visibility
The obstacle to seeing a meteor in daylight is the bright background of the sky itself, a phenomenon explained by Rayleigh scattering. This process involves sunlight interacting with the molecules of nitrogen and oxygen in our atmosphere. Shorter wavelengths of light, like blue and violet, are scattered much more efficiently in all directions than longer wavelengths, giving the sky its characteristic blue appearance and making it intensely bright.
This scattered sunlight creates visual “noise” against which meteors must compete. The brightness of a celestial object is measured using a logarithmic scale called apparent magnitude. Most meteors observed at night are relatively faint, and their light emission is too low to visually penetrate the brilliance of the scattered daylight.
When Brightness Overcomes Daylight
The atmosphere is occasionally struck by an object bright enough to overcome the scattered sunlight. These rare events involve much larger meteoroids, which produce intensely bright meteors known as fireballs or bolides. A fireball is defined as a meteor brighter than any of the planets, meaning it has an apparent magnitude of \(-4\) or greater.
When a meteoroid is large enough, the material burning up in the atmosphere generates a flash of light that briefly dominates the sky’s brightness. An even brighter event, a bolide, is often associated with an airburst or audible sounds, sometimes reaching an apparent magnitude brighter than \(-14\). The Chelyabinsk event in 2013 was a superbolide where the flash was briefly brighter than the Sun itself, making it clearly visible in the morning sky over Russia.
Non-Visual Detection of Daytime Showers
Daytime meteor showers are streams of debris that Earth encounters when the radiant point, the area from which the meteors appear to originate, is positioned near the Sun. These showers are impossible to see visually because their radiant is only above the horizon during daylight hours. The Beta Taurids, which peak around late June, are an example of such a daytime shower.
Scientists detect these showers using a technique called radio wave reflection, or meteor scatter. As a meteoroid enters the atmosphere, it creates a brief trail of ionized gas, or plasma, which acts like a temporary mirror high above the Earth. Radio signals from distant transmitters, normally blocked by the curvature of the Earth, can bounce off this ionized trail and be detected by a receiver hundreds of miles away. This non-visual method allows for the study of meteor activity during the day.