Bengaluru: Space is the next big frontier in human development, and private players are increasing their presence in the market each year.
This year, SpaceX CEO Elon Musk announced its ‘Starlink constellation’, a group of 12,000 satellites that will orbit Earth providing internet connectivity to remote areas. Meanwhile, Amazon CEO Jeff Bezos announced that his company Blue Origin will send up 3,200 satellites as part of ‘Project Kuiper’, also to provide internet connectivity across the globe.
SpaceX successfully launched 60 of its planned 12,000 satellites on 24 May. The satellites were caught streaking across the night sky like crawling mirrors, a previously unseen cosmic event.
The first 60 Starlink satellites captured less than 24 hours after launch by astronomer Marco Langbroek.
However, astronomers have raised alarm on what damage such bright objects in the sky could do to astronomy on Earth.
Musk mentioned in a tweet that providing internet connectivity to billions of economically disadvantaged people is the “greater good” in this situation. But that SpaceX will make sure to reduce reflectivity.
Exactly, potentially helping billions of economically disadvantaged people is the greater good. That said, we’ll make sure Starlink has no material effect on discoveries in astronomy. We care a great deal about science.
— Elon Musk (@elonmusk) May 27, 2019
Experts have already expressed scepticism, and increasing number of scientists and astronomical bodies have criticised SpaceX’s decision to not consult with a body of astronomers, scientists, and ethicists about launching an unprecedented number of satellites into the night sky.
Impact on astronomy
Earth-based astronomy relies on visually exposing telescopes for long periods of time to the night sky. The existing satellites in orbit, less than 2,000 of which are functioning, already cause bright streaks in images. These are caused when the metal satellites reflect sunlight from high orbits on to parts of the Earth that are facing away from the sun.
Such streaks mean entire data sets have to be discarded, and need to be recaptured at great expense. The Starlink satellites are much brighter and their trails much longer, potentially affecting optical astronomy a lot more.
The Large Synoptic Survey Telescope (LSST), a giant optical observatory in Chile, released a statement expressing concerns about Starlink and detailing the kind of problems optical astronomy is expected to face.
But it isn’t just optical astronomy; Starlink satellites also interfere with radio astronomy. The International Astronomical Union (IAU), the consortium of scientists and astronomers responsible for naming bodies and for global consensus on astronomy matters, put forth a strong statement condemning these satellites.
It stated that “despite notable efforts to avoid interfering with radio astronomy frequencies, aggregate radio signals emitted from the satellite constellations can still threaten astronomical observations at radio wavelengths”. Indeed, many path-breaking discoveries in the world of astronomical physics today, such as producing the first image of a black hole, have been due to radio astronomy.
Wider impact on Earth’s species
There’s also a third problem, something people of today don’t often have the perspective for since it doesn’t affect us anymore: Navigation using the night sky.
In the early days of human exploration, from pre-historic to pre-industrialised times, people used the night sky to find their way around. The most important navigational star was Polaris, the North Star, which is located at the north celestial pole and seems to stay still in the night sky. Thus, it is an excellent directional marker. Even today, there are 57 stars that are used as important markers for aviators and navigators during emergencies.
Humans are no longer reliant on just the night sky, but several other species are. Welsh ornithologist Robin Lockley famously proved that tiny seabirds called warblers used the night sky for navigation by observing the birds in a planetarium and moving the configuration of the stars on the dome. Dung beetles are famously known to navigate using clusters of bright stars and the Milky Way.
Several other species of insects and birds regularly use the night sky and stars for navigation. Bright and continuous flashes from all parts of the night sky could potentially disorient and confuse several creatures on Earth.