Lines of bright lights moving across the sky near dawn and just after dusk are increasingly causing people to wonder what it is they are seeing.
Perhaps not surprisingly, Elon Musk is involved.
SpaceX has been launching more and more Starlink satellites as Musk builds out his network of low-earth orbit satellites to provide global internet access.
In the first hours and days after launch the satellites can appear as trains of lights in the night sky.
SpaceX rockets that deploy the satellites launch from Cape Canaveral Space Force Station in Florida or Vandenberg Space Force Base in California, making the unusual spectacle more likely to be seen on the East and West Coasts of the United States.
Once they are released, the line of lights people are seeing are the satellites as they move together higher into space to the position of their final orbits. These can be seen as very bright lights for several days after launch before they travel too far up to be easily visible to the naked eye.
An informative video posted to Twitter by @TheNationalNews is a helpful explainer and shows how they look in the night sky.
Another video, posted by space reporter @thesheetztweetz, shows the view of the line of satellites from onboard a Starlink satellite moments after deployment from SpaceX's Falcon 9 rocket.
A television station in Raleigh, North Carolina explained the phenomenon to viewers of WRAL-TV (channel 5) after the bright lights were seen there. "In the days following a launch, they can be seen because though dark here on the ground, sunlight is still reaching these as they orbit at about 200 miles above the Earth," reported the station back in April.
To check when the train of lights might be seen near you, consult findstarlink.com.
Musk plans to begin launching larger satellites next year that will provide direct links to people's cell phones. Those will require successful launches of Musk's massive Starship, a fully reusable booster and spacecraft combo that stands nearly 400 feet tall on the launch pad.
Astronomers Have Concerns
SpaceX CEO Elon Musk has a worthy mission in providing Internet access, with "mega-constellations" of satellites, to people in remote locations far from cell phone towers, not to mention in war zones such as Ukraine. But many astronomers are upset with the appearance of the satellites in their photographic research.
At the Zwicky Transient Facility at Palomar Observatory, a study found that 5,300 streaks were seen in images it captured from November 2019 to September 2021. Astronomers guess that before too long, most twilight images taken by astrophotographers will be affected.
"This is concerning because twilight images are the most critically important to the search for near-Earth asteroids," reported Ashish Khadka of medium.com in March. "The potential meteor strikes that pose the greatest threat to us are those that are the most difficult to find because they come from a trajectory near the Sun’s position in the sky. And as the number of satellites rises to 10,000 or 15,000, astronomers will start to miss some asteroids. Astronomers expected that these numbers will be reached within a year or so."
One effort SpaceX has undertaken to help fix this problem is to begin adding a black sunshade to satellites that it suggests will dim the amount of sunlight reflected.
"Initial efforts at mitigating the spacecraft’s impact involved launching a prototype Starlink satellite later dubbed DarkSat in 2021, which featured a black antireflective coating," wrote EarthSky in September. "Ground-based observations of DarkSat in orbit found it half as bright as a standard Starlink satellite, which is a good improvement, according to experts, but still far from what astronomers say is needed."
