Too much clutter in night sky
Anyone who has spent time observing the night sky has noticed tiny, bright, pin-point spots of light speeding across the heavens, often appearing and disappearing at random.
Though some may think they are UFOs, most people know these are man-made satellites, launched into low-Earth orbit (LEO) for a variety of communication, research, and surveillance purposes.
For the most part, unless you happen to be taking a time-exposure photo of the night sky, they are of no consequence to the average observer, merely an interesting and unexpected surprise. Since they are so high up, very tiny, and rather dim, most pass overhead unseen.
That is about to change. In 2019, space entrepreneur Elon Musk launched the first 60 SpaceX Starlink satellites into LEO, followed by more launches throughout 2020.
The 17th launch occurred Jan. 20, bringing the current number of Starlink satellites into orbit around the Earth to more than 1,000 — that's in addition to the 3,000 satellites already in orbit. SpaceX has already received permission from the U.S. Federal Communications Commission (which oversees communication networks across multiple industries, and thus most global satellite launches) to put 12,000 more Starlink satellites into orbit, with plans to have more than 30,000 eventually in orbit.
Other companies, notably Amazon and OneWeb, have jumped onto the trillion-dollar worldwide internet-connectivity market bandwagon, with plans to launch 3,236 and 2,000 satellites respectively.
SpaceX hopes to capitalize on its rideshare program that will assist other national and international commercial and government customers to cheaply put their satellites into orbit by collectively sharing the launch costs. SpaceX's stated purpose is to bring high-speed broadband internet access to places on the globe not currently served by other communication technologies, although current analysis indicates the cost of internet access in most of these areas would be prohibitive (something that has an estimated US$30 billion annual revenue for SpaceX).
ASTRONOMICAL ISSUE
The potential problem that 35,000-plus satellites pose to astronomers is significant. When Starlink satellites are launched in groups, they spread out into what are referred to as satellite trains or constellations — long strings (like a pearl necklace) of lights crossing the night sky at an altitude of 550 kilometres.
Like all satellites, the Starlink satellites are made of metal (highly reflective) and, when lit by sunlight, shine like a "moving star", significantly and negatively impacting both amateur and professional observations and research. Time exposure astrophotography for professional observation and research purposes is jeopardized when the constellations of satellites obscure the object being viewed, and the astrophoto is ruined. Another significant problem is the potential interference with NASA's observation of nearEarth asteroids, leaving our planet vulnerable to potential world-altering impacts when the telescopes watching for the asteroids are confused by the light of the moving satellites.
To its credit (but only after loud complaints from the global astronomy community), SpaceX is trying to come up with a means of either dimming or eliminating the brightness of the satellites by shielding them with a sunshade or dimming them with an anti-reflective coating. Such measures will take time to assess and in the meantime, the launches continue.
SPACE JUNK
In addition to the light-polluting problem with all these satellites, they also contribute to the enormous amount of orbital debris or space junk circling the planet. There are currently more than half a million pieces of space debris being tracked by NASA. About 21,000 are larger than a softball, and over 500,000 are the size of a marble or larger, with millions of pieces too small to be tracked. Add to this number an additional 35,000-plus satellites zipping around at 28,000 kms/hour, and you can well imagine the increased potential for what scientists refer to as the Kessler Syndrome, where collisions between satellites or space debris cause a runaway cascade of collisions, resulting in the destruction of or damage to many satellites or other spacecraft.
These collisions could add countless more pieces of orbital debris to the already huge number of orbiting debris pieces, compounding the problem further. Such collisions and the resulting space debris could pose significant threats to the International Space Station, future commercial space flights, and even future missions to the moon and Mars. Large satellites and large debris objects, if knocked earthward, could pose a threat to people on the ground if they survive reentry and strike a populated area.
Though many people don't care about additional bright lights streaking across the night sky, there is much to be lost if it becomes saturated with artificial lights. Not only will valuable scientific observations and research opportunities be compromised, but sadly, our historical connection to the night sky will be lost. From the nights when early humans first pondered the mysteries of the heavens to the elaborate stories and myths ancient civilizations associated with the constellations and the contributions astronomy has made to the advancement of science, we have always been connected spiritually and emotionally to the stars. We are, after all, made of stardust so naturally,
we have an affinity for them. To lose this connection for the sake of artificial entertainment is lamentable.
THIS WEEK’S SKY
As with last week, planet observations this coming week are limited. Mercury, Venus, Jupiter, and Saturn are all too close to the sun to be readily observable. Mercury will achieve inferior conjunction with the sun on Feb. 8.
The only planet observable this week is Mars. Shining at magnitude +0.5 in Aries — the Ram, the red planet becomes accessible shortly before 6 p.m., 60 degrees above the southern horizon, remaining observable until about 12:15 a.m., when it drops below 10 degrees above the western horizon.
NASA's Mars 2020 spacecraft, with its Perseverance Rover, is due to arrive at the planet on Feb. 18.
Until next week, clear skies.
EVENTS
• Feb. 3 — Moon at perigee (closest to Earth)
• Feb. 4 — Last quarter moon
Glenn K. Roberts lives in Stratford, P.E.I., and has been an avid amateur astronomer since he was a small child. His column, Atlantic Skies, appears weekly.