Scientists from the International Astronomical Union (IAU) recognized the prototype BlueWalker 3 satellite of the American telecommunications company AST SpaceMobile as one of the brightest objects in the night sky. This may interfere with astronomical observations. Article published In the scientific journal Nature.
BlueWalker 3 is a giant 63 square meter dish antenna deployed 500 km above the Earth. The device was launched into orbit in September 2022.
After the antenna was fully deployed, its surface began to shine with a strength of 0.4 apparent magnitude when observed from Earth, thus becoming one of the ten brightest stars in Earth’s night sky.
In the system of rating the brightness of stars, a lower number means greater brightness, and superluminous objects can have negative values; for example, the brightness of the Sun is -27, and the brightest star after it is Sirius – 1.46.
Thus, the mirror of BlueWalker 3 shines brighter than the brightest star (alpha) of the Orion constellation Betelgeuse (0.5), and in terms of visibility it is with alphas of the constellations Eridanus and Canis Minor – Achernar (0.46) and Porcyon (0.38) comparable.
The presence of such bright artificial objects in the sky hinders astronomical observations. According to the recommendations of the International Astronomical Union, the brightness of the satellites should not exceed 7. With this indicator, satellites can be removed from the images using artificial intelligence, while strong lighting irreversibly distorts the images. BlueWalker 3 is 400 times brighter than the IAC limit. The problem may worsen in the future, as AST plans to place 90 more such facilities in orbit.
“This satellite was launched with little attention to its impact on astronomy. The IAU is committed to changing this and working with the space industry on solutions,” said study co-author Siegfried Eggl.
Experts suggest that the satellite problem be solved by increasing the satellite to a geostationary orbit of 35 thousand km from the current 500 km. This will reduce the brightness of the device to 99.98% of what it is.
Earlier astronomers introduced A special term describing the feeling of sadness felt when stars cannot be seen due to light pollution.