The Night Sky

(Editor’s note: As part of nature observations columns, three monthly features will present topics related to our atmosphere and skies. This first feature will address our night sky.)

When you go camping this summer or sit outdoors and look up at the stars, you may notice every few minutes a satellite slowly streaking somewhere in the night sky – faint, and only visible before the moon comes out, but with striking frequency.

With our often clear night skies in New Mexico, this may puzzle the casual observer. A scientific article in Nature (March 20, 2025) points to a growing problem in astronomy: the expanding number of satellites that interfere with astronomical studies.

The picture to the right provides an example of streaks in the night sky from a group of satellites. The other picture illustrates the number of satellites (about 11,000) encircling earth in 2025.

Of course, satellites play a crucial role in connecting people and help first responders, but the rising number of satellites also interfere with ground-based astronomical observations by creating bright streaks on images and by their emission of electromagnetic interference with radio telescopes. The issue of satellites interference is expected to be a growing problem, especially with the upcoming rise in direct-to-cell satellites which are bigger and also produce powerful transmissions that impact radio astronomy measurements.

Astronomers can review satellite trackers databases to tailor their observations to specific parts of the sky or by pausing observations when satellites fly by, but that technical support is not fully reliable. Satellites manufacturers are considering design modifications to limit the satellites’ brightness.

Also, discussions on respect of the night sky have included the rights of Indigenous people against light pollution or satellites. The skies are a global resource, shared by all of humanity.