Ruprecht-Karls-Universität Heidelberg

Measuring the Universe 3.0

The European science satellite Gaia has been observing the entire universe since spring 2014 and creates gigantic object catalogues with data on our solar system, the Milky Way distant objects beyond our galaxy. On Thursday, 3. December 2020, a part of the so-called third Gaia data catalogue will be published. Then information on almost 1.8 billion celestial bodies will be accessible. The international science community is looking forward to this moment, which is being accompanied by an online event organized by ESA. Scientists from Heidelberg are significantly involved in the release and presentation.

Gaia is by far the most successful science mission of the European Space Agency (ESA). For nearly seven years, the satellite has been measuring, among other things, the distances, movements and properties of around 1.5 billion stars of the Milky Way with a precision that far exceeds all available data. Four years after the measurements began, the first Gaia star catalogue was made available for science on 25 April 2018. This moment was eagerly awaited by as it marked the beginning of a new era in the exploration of the Milky Way.

Since then, the data published at the time have triggered a revolution in our knowledge of the origin and structure of our home galaxy. The number of scientific publications produced on the basis of the previous data currently stands at around 4300. Gaia is already now more successful than the Hubble Space Telescope.

A part of the third Gaia data catalogue will now be published on 3 December 2020 at 12:00 CET (Central European Time). Not only will data on new celestial bodies be available, but the previous information on stars and celestial bodies will also be presented with much improved accuracy after three years of further measurements. On this occasion, the space management of the German Aerospace Agency- (DLR) is organising an international online event with its German Gaia partners to present the uniqueness of this third data catalogue and the Gaia mission to the public.

In Heidelberg, the Gaia Data Reduction and Analysis Consortium (DPAC) is run by the Astronomisches Rechen-Institut (ARI), which is part of the Center for Astronomy at the University of Heidelberg (ZAH). Among other things, the ARI developed a highly complex software that monitors the correct functioning of all systems on board and the quality of raw scientific data on a daily basis since the satellite was launched. The ARI team of experts and scientists also leads the Pan-European astrometry department, which ultimately extracts from trillions of measurements the data scientists need to significantly expand our knowledge about the origin and structure of our home galaxy. ARI also hosts one of six Gaia data centers, and coordinates the "Gaia Ground Based Optical Tracking", whose task is to accurately monitor the satellite's position in the sky and measure its motion at 2.5 millimeters per second as one of the manyfold prerequisites for ultra-precise astrometry.

Scientists and engineers from more than 20 European countries are jointly working together on the Gaia mission. Germany is the largest contributor to the ESA science programme.The German Space Agency (DLR) on behalf of the Federal Government supports Gaia's German contribution at the following institutes: the Astronomisches Rechen-Institut (ARI) at the Center for Astronomy of Heidelberg University, the Leibniz Institute for Astrophysics in Potsdam, the Max Planck Institute for Astronomy in Heidelberg, and the Technical University of Dresden. 

Information about the online event
Livestream YouTube:
Programme with Live Stream:

Dr. Anke Pagels-Kerp - DLR Space Management
Dr. Michael Biermann - Center for Astronomy of Heidelberg University
Dr. Katja Weingrill - Leibniz Institute for Astrophysics Potsdam
Prof. Dr. Sergei A. Klioner - Dresden University of Technology, Lohrmann Observatory
Prof. Dr. Stefan Jordan - University of Heidelberg, Center for Astronomy
Dr. Coryn Bailer-Jones - Max Planck Institute for Astronomy, Heidelberg

Sebastian Funk, science journalist and physicist (Twitter@herrfunk)

Additional information
- HOMEPAGE of the ESA with information about Gaia:
- HOMEPAGE of ESA with informationon scientificresults:
- Homepage of the ZAH with local and further information about the Gaia project:

Dr. Guido Thimm
Center for Astronomy at the University of Heidelberg (ZAH)
- ZAH Public Relations -
Tel. +49 6221 54-1805

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