ann23032 — Announcement

100 Hours of Astronomy 2023
26 September 2023
100 Hours of Astronomy 2023

From 1 to 4 October 2023, the IAU Office for Astronomy Outreach (OAO) will hold a 100-hour, round-the-clock, round-the-globe celebration of astronomy. The event will continue the legacy of celebrating 100 Hours of Astronomy, which began during the International Year of Astronomy 2009. The OAO encourages everyone to get involved, aiming to engage as many people as possible from all age groups and backgrounds with the wonders of the night sky and the Universe.

This year’s 100 Hours of Astronomy event has the special theme One Planet, which is intended to foster a sense of unity, connection, and togetherness among the public, inspired by the Overview Effect [1] — the camaraderie astronauts often feel when viewing the Earth from space. The activities planned for this year’s event will celebrate the beauty of our shared planet and promote global cooperation, environmental stewardship, and a collective commitment to a better future.

The Overview Effect

The Overview Effect refers to a profound and transformative shift in consciousness that astronauts often experience when viewing Earth from a distance during space missions. It is a cognitive and emotional response to the breathtaking sight of our planet from orbit or from the Moon. The Overview Effect is often described as embodying the following elements:

  • Awe and unity: Astronauts describe an overwhelming sense of awe and unity as they gaze upon Earth from space. They see the planet as a fragile and interconnected ecosystem devoid of boundaries and divisions.
  • Increased environmental awareness: The experience fosters a deep appreciation of Earth's beauty and a heightened awareness of environmental challenges. Many astronauts return to Earth with a strong commitment to protecting the environment.
  • Shift in perspective: The Overview Effect often leads to a shift in perspective, including a recognition of the futility of individual conflicts and the importance of cooperation to address global issues.
  • Spiritual and philosophical insights: Some astronauts describe the experience as spiritual or philosophical, leading to a reevaluation of their life's purpose and a sense of interconnectedness with all living beings.
  • Motivation for space exploration: The Overview Effect has also served as motivation for further space exploration, as astronauts return with a sense of responsibility to explore space while ensuring the preservation of Earth.

The Overview Effect underscores the profound impact that space travel can have on the human perspective, as well as the importance of safeguarding our planet and working collaboratively to address global challenges.

100 Hours of Astronomy IAU Calendar of Global Outreach Events

As in previous years, the OAO will host a global map of events in which you can share your work with the world and be a part of the OAO’s 100 Hours of Astronomy. You can add your event to this calendar via the online submission form. If your event is open to the public, be sure to leave enough information for people to join in — both in person and online. The first 50 events that enter their information will receive goodies from the OAO, including printed copies of the most recent CAPjournal issues. Be safe [2], be inclusive, and share your event with the world!

100 Hours Art Projects Competition

The OAO is excited to offer participants the opportunity to engage in a collaborative art project that symbolises unity and interconnectedness. To contribute to the collective artwork, create a piece of art: a painting, picture, poem, video, or any other creative medium, and submit it through this form before 10 October 2023, 23:59 UTC. We invite artists of all ages to join in the competition. By sending us your artwork, you agree for it to be shared on the IAU OAO social media pages, with your name linked to it. We will randomly select two entries to win a telescope courtesy of Sterren Schitteren Voor Iedereen (Stars Shine For Everyone – SSVI), Ghent University Department Physics and Astronomy, Leiden University, and BRESSER.

Activity ideas

Do you need some ideas for your astronomy outreach event? Look through the community-driven ideas in the OAO Toolkit. If you have developed or know of any exciting astronomy outreach activity format, please share it with the community by submitting it through this form. Additionally, you can look through last year's events at the 100 Hours of Astronomy 2022 page.

Sharing activities on social media

When spreading the word about your event on social media, be sure to use #100HoursOfAstronomy and #IAUoutreach so that the OAO can help promote your activity, too.

Stay tuned to the OAO’s social media channels — Facebook and X (Twitter) — as we release more information and resources in the upcoming weeks.

More information

The IAU is the international astronomical organisation that brings together more than 12 000 active professional astronomers from more than 100 countries worldwide. Its mission is to promote and safeguard astronomy in all its aspects, including research, communication, education and development, through international cooperation. The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and the surface features on them. Founded in 1919, the IAU is the world's largest professional body for astronomers.


[1] Yaden, D. B. et al.2016, The overview effect: Awe and self-transcendent experience in space flight, Psychology of Consciousness: Theory, Research, and Practice, 3(1), 1

[2] Please follow the health and safety measures recommended by your country or local area when joining the 100 Hours of Astronomy activities.


Andrea Girolamodibari
100 Hours of Astronomy 2023 Project Manager

Kelly Blumenthal
OAO Acting Director
Tel: +81 80 8841 3569

Lars Lindberg Christensen
IAU Director of Communications
Cell: +1 520 461 0433/+49 173 38 72 621

About the Announcement



100 Hours of Astronomy 2023