From exoplanets in Ecuador to stars in South Korea, today sees the start of a special global science-outreach event called “100 Hours of Astronomy”. Running from 10-13 January, the event is taking place over three nights and four days at more than 500 different venues in 79 different nations around the world.

First held in 2009 as part of the International Year of Astronomy, this year’s 100 Hours of Astronomy event will bring together amateur and professional astronomers, astronomy enthusiasts and members of the public to share their knowledge and enthusiasm for the subject. You can find out exactly what’s going on in your country at the 100 Hours of Astronomy list of registered events.

The self-styled “global starparty” is the first in a series of initiatives being held throughout 2019 to mark the centenary of the International Astronomical Union (IAU).

Going under the banner “Under one sky”, the IAU’s year-long celebrations are designed to “increase awareness of a century of astronomical discoveries as well as to support and improve the use of astronomy as a tool for education, development and diplomacy”.

The IAU centenary initiatives includes exhibitions, teaching tools and outreach activities – as well a flagship meeting on 11–12 April 2019 at the Palace of the Academies in Brussels, Belgium.