Sigma Pi Sigma, the Physics and Astronomy Honor society
Sigma Pi Sigma exists to honor outstanding scholarship in physics and astronomy, to encourage interest in physics and astronomy among students at all levels, to promote an attitude of service, and to provide a fellowship of persons who have excelled in physics and astronomy. Founded in 1921, Sigma Pi Sigma is a member honor society of the Association of College Honor Societies. Election to Sigma Pi Sigma is a lifetime membership.
Our Members are Leaders in Physics and Astronomy
Every year we induct future leaders in physics and astronomy who have demonstrated academic excellence and dedication to service. When you accept an invitation to Sigma Pi Sigma, you join a vibrant network of over 100,000 scientists, educators, and advocates.
Build Lifelong Connections
Local chapter events, the Physics and Astronomy Congress, and special events present opportunities for lifelong learning and connection to the physics and astronomy community.
Receive Exclusive Member Benefits
Members receive a lifetime subscription to Radiations, the official publication of Sigma Pi Sigma, and are eligible for awards and scholarships.
Give Back to the Community
Through fundraising, outreach, and other service opportunities, Sigma Pi Sigma chapters support the next generation of scientists and promote the value of science in society.

Induction Process

Our History

Physics & Astronomy Congress
Highlights from Radiations, the official publication of Sigma Pi Sigma
More from Radiations
2025 Physics and Astronomy Congress Speaker
On April 8, 2024, parts of North America experienced a total solar eclipse, and much of the rest of the continent experienced a partial eclipse. In the spring issues of Radiations and the SPS Observer, we asked members to submit their eclipse stories and photos. You did not disappoint! Please enjoy this collection of reflections and images.
In 2023 the society announced the new Sigma Pi Sigma Leadership Scholarships, created to honor society members within ten years of their induction date who are pursuing an advanced education in physics, astronomy, or a closely related field. The initial scholarships were awarded thanks to a generous donation from longtime SPS supporter and AIP board director Jack Hehn, through the Hehn Family Charitable Trust. Here, two of these scholars reflect on their undergraduate journey, their membership in Sigma Pi Sigma, and how the Leadership Scholarship is supporting the next stage of their journey.