This article was written by site member Tom Urbain. This is the second Galactic Hunter post written by an outside contributor. If you would also like to write about an astronomy related subject that inspires you, you can contact us by e-mail at firstname.lastname@example.org to have your article featured on our website.
What is Starlink?
On April 22, 2020, SpaceX (led by Elon Musk) launched another batch of satellites into space from the Kennedy Space Center in the United States. Theses satellites have joined the existing “Starlink Constellation” in orbit around the earth since February 2018 and they have had extensive press coverage lately.
During the past few weeks, many people have been posting pictures of the night sky displaying the famous train of 60 satellites from the Starlink program. Many amateur astronomers have voiced their concerns that the luminous streak of satellites across the sky may impair their ability to enjoy the night sky.
But what is Starlink and what is its purpose?
Starlink, The Satellite Constellation
In essence, Starlink’s satellite constellation is designed to provide cheap Internet access to any part of the world… even to the most recluse part of the Planet.
Elon Musk is going big with this project: he plans to put 12,000 satellites into orbit by 2025 and 42,000 satellites into orbit by 2030 if he obtains the necessary authorizations. Each satellite will be placed in a low orbit, between 350 km and 1500 km in altitude. This makes it possible, in terms of telecommunications, to have a better performance in terms of internet speed. Latency is much lower compared to geostationary satellites based at 36,000 km altitude.
While this sounds good on paper, is it really worth it? Starlink does raise some concerns in the scientific community.
A visual impact on stargazing
There has been an increasing number of reports and images posted on social media showing Starlink satellites traveling through the night sky. Professional and amateur astronomers are mobilizing, questioning and seeking answers about the visual impact this satellite network will have on stargazing. Many fears that the increasing number of satellites will invade the night sky and make telescopic observation very difficult.
It turns out that each satellite, as the sunlight reflects off its solar panel, creates a flash of light for a few seconds, day and night. Like a star that grows very quickly, with intense light, only to disappear afterwards. It’s easy to understand how badly this may impact the ability to observe planets, stars and galaxies as well as taking pictures of them.
A “Noisy” impact on radio astronomy
Another subject to consider is the radio waves emitted by Starlink satellites... Indeed, astronomers also study the radio waves emitted by the stars. It is radio astronomy that has enabled a better understanding of the structure of our galaxy, the evolution of nebulae, the birth of stars, and much more...
This research is carried out by using gigantic dishes measuring up to 500 meters in diameter: radio telescopes.
Because these radio signals coming from the universe are very weak, there are now concerns that theses telescope’s ability to pick up those signals might be disrupted by the powerful waves emitted by these new satellite arrays.
This would deprive scientists of important data for understanding the Universe.
A Risk of collision
Concerns about possible collision are also rising, as Starlink is not the only project for a constellation of satellites in low orbit. A company called OneWeb is working on its own project and even Amazon is going to launch its satellite constellation, called the Kuiper project. In total, there could be more than 45,000 satellite that could be launched over the next few years, whereas there are currently just over 2,200 satellites around the Earth.
In September 2019, the European Space Agency warned of the increased risk of collisions after having to modify the trajectory of one of their scientific satellites in order to avoid a collision with a Starlink satellite.
This increasing probability of collisions also raises the question of space debris. As satellites travel at speeds close to 30,000 km/h, the slightest incident can generate a very large number of debris, which in turn can hit other objects, leading to a chain reaction.
For now, it seems that SpaceX and a few other companies will go ahead with their plans no matter what. Elon musk keeps stating on Twitter that he is listening to astronomers concerns and that his company his working on various solutions. This includes placing the satellites into a slightly higher orbit, and reducing their reflectivity: parts of the satellite would be darkened to reduce its reflectivity and hence brightness.
But will this be enough?
Big thanks to Tom Urbain for writing this post! You can visit his website here.
GALACTIC HUNTER BOOKS
Description: Discover 60 Deep Sky Objects that will considerably improve your Imaging and Processing skills! Whether you are a beginner, intermediate, or advanced astrophotographer, this detailed book of the best deep sky objects will serve as a personal guide for years to come! Discover which star clusters, nebulae, and galaxies are the easiest and most impressive to photograph for each season. Learn how to find each object in the night sky, and read our recommendations on imaging them in a quick and comprehensive way. Each target in this guide contains our advice on imaging, photos of expected results, and a useful information table. We've also included a few cool facts about each target, a map to find it in the night sky, and more!
Description: The Astrophotographer’s Journal is a portable notebook created for the purpose of recording observations, cataloguing photographs, and writing down the wonderful memories created by this hobby. This book contains more than 200 pages to memorialize your stargazing and imaging sessions, as well as a useful chart on the last pages to index exciting or important notes. Read back on the logs to see how much progress you have made through the months, the problems you overcame, and the notes taken to improve in the future. Just as the pioneers of astronomy did in their time, look up and take notes of your observations as you are the author of this star-filled journey.
Description: The Constellations Handbook is a logical guide to learning the 88 constellations. Learning the constellations is difficult. Remembering them is even harder. Have you ever wanted to look up to the night sky, name any pattern of stars and be able to tell their stories? This book groups the constellations in a logical order, so that the reader can easily learn them by their origin, and see how their stories interact with one another as a group. The last pages of this book include an index of all 88 constellations, each with a slot where you can write your own personal tips and tricks in order to memorize them with ease. The Constellations Handbook is not just another guide listing all the constellations from A to Z and their location, it is the perfect companion for stargazing, and a learning journey through the ages.