  The rising population of artificial satellites and associated debris in
low-altitude orbits is increasing the overall brightness of the night sky,
threatening ground-based astronomy as well as a diversity of stakeholders and
ecosystems reliant on dark skies. We present calculations of the potentially
large rise in global sky brightness from space objects, including qualitative
and quantitative assessments of how professional astronomy may be affected.
Debris proliferation is of special concern: since all log-decades in debris
size contribute approximately the same amount of night sky radiance,
debris-generating events are expected to lead to a rapid rise in night sky
brightness along with serious collision risks for satellites from
centimetre-sized objects. This will lead to loss of astronomical data and
diminish opportunities for ground-based discoveries as faint astrophysical
signals become increasingly lost in the noise. Lastly, we discuss the broader
consequences of brighter skies for a range of sky constituencies,
equity/inclusion and accessibility for Earth- and space-based science, and
cultural sky traditions. Space and dark skies represent an intangible heritage
that deserves intentional preservation and safeguarding for future generations.
