IAU Sky and Telescope

Title: The Brightest Star in the Sky? A New Satellite's Impact on Ground-Based Astronomy

As astronomers gaze up at the celestial canvas, they often find themselves in awe of the twinkling lights that dot the horizon. From ancient civilizations to modern-day stargazers, humans have long been fascinated by the mysteries of the universe. But a new development is threatening to disrupt this centuries-old tradition – a prototype satellite brighter than all but seven stars in the night sky.

BlueWalker 3, launched by Texas-based company AST SpaceMobile in 2022, was designed to test the feasibility of a mobile phone network orchestrated from space. While its purpose may be noble, its impact on ground-based astronomy is proving to be a major concern. The satellite's 64-square-metre reflective antenna makes it brighter than most stars in the sky, causing astronomers to worry about data loss and potential damage to detectors.

'This presents a significant threat to ground-based astronomy,' says Siegfried Eggl, an astronomer at the International Astronomical Union. 'Wide-angle surveys of the night sky, such as one that will be carried out at the Vera C. Rubin Observatory, could be severely impacted.'

To mitigate this issue, astronomers are exploring tracking and avoidance strategies to minimize the satellite's impact on observations. However, these methods can still fail due to the difficulty in tracking satellites. 'If there's a bunch of these really bright objects, I think the danger is that there's going to be potential large-scale data loss, if not damage to detectors,' warns Eggl.

The discovery of BlueWalker 3's brightness has sent shockwaves through the astronomy community. A year-long monitoring campaign using telescopes in the US, Chile, the Netherlands, and New Zealand confirmed its extraordinary luminosity. In fact, it's even brighter than previous measurements suggested, with a similar brightness to the brightest stars in the constellations Canis Minor and Eridanus.

As more satellites like BlueWalker 3 enter orbit, astronomers will need to adapt their methods to accommodate these new celestial neighbors. 'If telescopes adopt tracking and avoidance strategies, they might need to periodically shut down while a satellite moves over their line of sight,' notes Eggl. 'This could delay observations or skew datasets.'

The impact on astronomy is far-reaching, with potential implications for our understanding of the universe. 'Astronomy has long been used as a tool of survival,' says Eggl. 'From determining calendars to predicting seasonal behavior, humans have relied on the stars to navigate space and time. It's crucial that we find ways to mitigate this issue to ensure the continued success of ground-based astronomy.'

As we gaze up at the night sky, it's clear that our relationship with the universe is evolving. While technology has opened up new possibilities for exploration and communication, it also brings new challenges for astronomers. The discovery of BlueWalker 3 serves as a reminder of the importance of responsible satellite development and the need for continued innovation in astronomy.

In conclusion, the brightest star in the sky may not be a star at all – but a prototype satellite with far-reaching implications for ground-based astronomy. As we navigate this new era of space exploration, it's crucial that we find ways to balance technological advancement with astronomical preservation. Only then can we ensure that our gaze up at the stars remains undisturbed, and the wonders of the universe remain within our reach.

Iau sky and telescope