New satellites have become one of the brightest objects in the night sky, raising fears among scientists about the future of astronomy.
According to a new study published in the journal Nature, the bright paths of satellite BlueWalker 3 and other new satellites are likely to shine as brightly as the neighboring planets in the night sky, making it difficult for astronomers to observe the universe without streaks of light pollution from such satellites.
BlueWalker 3, a communications satellite prototype, includes a 692-square-foot array, which is a huge flat surface that acts like a mirror and reflects sunlight back to Earth. According to the research, the magnitude of the satellite’s greatest brightness is 0.4.
“The startling conclusion from our study is that the BlueWalker 3 satellite is one of the brightest things in the sky,” said Meredith L. Rawls, co-author of the paper and astronomy research scientist in the Department of Astronomy and DiRAC at the University of Washington, while speaking to Newsweek.
“Keep in mind, astronomers use a magnitude system, which is “backward”—brighter objects have smaller magnitudes, so 0.4 is quite bright,” explained Rawls.
“There are only about six stars that are brighter in the night sky than this. For context, the way magnitudes work is, something that is magnitude 2 is only about 40 percent as bright as something that is magnitude 1. The unaided eye can see objects down to about magnitude 7 from a very dark site. Venus’ apparent magnitude in the sky is about -4 (it’s extremely bright!),” he added.
Asteroid detection is being hampered by light pollution
A lower magnitude indicates that the object is brighter. The sun has a magnitude of -27, while the full moon has a magnitude of -13.
“While there is only one BlueWalker 3 so far, it is important to characterize its brightness and understand its impact, since many groups are planning to launch many bright satellites to LEO [low Earth orbit] in the near future,” said Rawls.
BlueWalker and other bright satellites in the night sky present concerns due of the amount of light they reflect back to the ground.
Rawls explained in an article published on Astronomy.com that the light reflected by satellites will hinder the detection of objects, which include near-Earth asteroids, during the twilight hours.
“The problems here on Earth range from interference with astronomical observatories doing sky surveys to a possible interference with migrating birds being misdirected due to its appearance,” said Brad Young, co-author and lead coordinator of visual observing at the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference, which is based in Paris, while speaking to Newsweek.