April 9, 2024

TiSpeaker: Aparna Venkatesan (University of San Francisco)

Contact Information: avenkatesan@usfca.edu

Title: The Cost of Brightening Night Skies on Ground-Based Astronomy

Abstract: Dramatic rises in ground-based light pollution in recent years as well

as increasingly congested low-Earth orbits are leading to brightening

night skies worldwide, with consequences reaching far beyond this

decade. I share calculations of the potentially large future rise in

global sky brightness from space objects in low Earth orbit (LEO),

including qualitative and quantitative assessments of how ground-based

astronomical observations may be affected. Debris proliferation is

especially a concern: all log-decades in debris size may contribute

approximately the same amount of night sky radiance, and given the

rising risk of debris-generating events in LEO, this could lead to rapid

rises in global night sky brightness. This will in turn lead to

increased loss of astronomical data and diminished opportunities for

ground-based discoveries as faint astrophysical signals become

increasingly "lost in the noise". This will affect many constituencies

beyond professional astronomy that are reliant on dark and quiet skies,

including Indigenous communities' sky traditions, animal/bird migratory

patterns, amateur astronomy, astrotourism, human/animal circadian

rhythms, and the seasonal and pollination cycles of plants. Globally

coordinated regulatory policies and mitigation strategies are urgently

needed to protect the shared environment and intangible heritage of

space and dark skies for future generations.

Visitor's room: 127

Visit Schedule:

Tuesday (April 9, 2024):

Tuesday (April 9, 2024), Alchemist and Barrister

STUDENTS HAVE PRIORITY.

PLEASE NO MORE THAN 8 PEOPLE (it is more difficult to properly interact with the speaker in larger groups).