Recently there have been many sightings, here in Aotearoa and around the world, of strange lights in the sky… Are they UFOs or something more easily explained?

 

These sightings have been described as ‘dozens of lights moving like a train’ that appear to be moving ‘in formation’ across the night sky and were recently spotted and recorded in several locations across New Zealand. However, these strange new lights are no UFO, they are the latest stunt from billionaire turned rocket engineer Elon Musk, CEO of Space X. These are the newest satellites from Space X known as Starlink, designed to bring global internet coverage to virtually every person on Earth. There have already been four Starlink launches, with each launch sending a batch of 60 new satellites into orbit above us. So, why are there so many being launched? Will this affect our night sky?

Space X in recent years has risen to become one of the most revolutionary and leading players in the space industry. They made history by developing the Falcon 9 rocket, which is a reusable rocket booster, capable of launching a payload into orbit and then falling back to land precisely on solid ground or special barges placed out at sea. This has dramatically dropped the price of launching payloads into orbit with their rocket significantly, meaning more customers are able to launch satellites at a lower cost. Space X’s goal has always been to open the space industry and make it accessible and cheaper for everyone. They are also developing rockets to launch and land payloads to the Moon, Mars, and beyond with a goal of colonizing Mars, eventually. But this development comes at a cost.

Space X relies on launching customer payloads into space to generate revenue, but Elon Musk had come up with a concept to bring global internet coverage to everyone to generate income. This network, or ‘constellation’ of satellites was named Starlink, and the initial plan is to have 12,000 Starlink satellites in orbit above the Earth. Space X plans to sell this internet to customers to produce revenue. The benefit of having so many satellites means there will always be several providing coverage to any given location on Earth at any given time, and the lower orbital altitude means there will be less latency (delay) with connection.

 

A train of Starlink Satellites passing over Pukehina, New Zealand. Image Credit: Astrofarmer

There has been some concern over adding an additional 12,000 satellites to our night sky and what effect it might have for astronomers and stargazers alike. Satellites have been launched into orbit since the late 50s, and to date there has already been tens of thousands of large objects launched in orbit above the Earth. Many, are operational satellites that give us internet and TV, while others, are dead satellites or old rocket boosters with no functional use. The majority of the objects above us are no longer in use, and you can usually spot many orbiting objects if you watch the sky after sunset on any clear night. An important thing to remember about satellites is that they do not produce their own light. Satellites reflect light from the Sun, so they can only be seen after sunset while they are still at a high enough altitude from our perspective to be illuminated by the Sun. Once they pass into the Earth’s shadow, they become virtually invisible. You may have noticed satellites moving across the sky before, only to see them suddenly ‘disappear’. This is why we cannot see satellites in the middle of the night as there is no light in the shadow of the Earth that can illuminate them sufficiently to been seen with the naked eye.

Another important factor to remember about the Starlink satellites, is that they are launched in batches of 60 at any given time. They are initially very close together after being deployed at launch, but they eventually spread across a larger area within their orbit over a few days. Space X then moves them to a higher altitude, meaning their brightness is dramatically reduced and they become virtually invisible after a few days of launching. All the recent sightings of the Starlink satellites have occurred in the days right after launch. They are very close together and a lot closer to the ground, but their effects on the sky are mitigated once they have been moved to a higher and more spread out orbit.

 

A batch of 60 Starlink Satellites in Earth orbit before deployment. Image Credit: SpaceX 

Other objects in orbit, like the International Space Station for example, are far brighter than the Starlink satellites and can often out-shine even the planets, yet there never seems to be any complaints about those crossing our skies. For every new launch of Starlink, they will only be visible for a few days following the launch, but this is a great time to get out and try and spot this dazzling light show above us before they fade from view.

Josh Kirkley, Astronomy Educator

Front title image credit: Astrofarmer